WO2019145544A1

WO2019145544A1 - Altered starch producing plants

Info

Publication number: WO2019145544A1
Application number: PCT/EP2019/052015
Authority: WO
Inventors: Stefanie HARTJE; Habil. Eckhard TACKE
Original assignee: Böhm-Nordkartoffel Agrarproduktion Gmbh & Co. Ohg
Priority date: 2018-01-26
Filing date: 2019-01-28
Publication date: 2019-08-01

Abstract

Described are starch producing Solanum plants and starch obtainable from those plants. In particular, potato plants are provided which due to an allele dosage effect in the combination with loss-of function mutations in at least two endogenous genes encoding enzymes involved in starch biosynthesis are capable of producing starch with improved physicochemical properties. Furthermore, starch with said altered physicochemical properties obtainable from those potato plants as well as the use of the starch in food and industrial processes are disclosed.

Description

Altered starch producing plants

FIELD OF THE INVENTION

The present invention relates to the field of starch producing Solanum plants and starch obtainable from those plants. In particular, the present invention relates to potato plants which due an allele dosage effect in combination with loss-of function mutations in at least two endogenous genes encoding enzymes involved in starch biosynthesis are capable of producing starch with altered, preferably improved physicochemical properties compared to corresponding wild type plants and plants which do not show said allele dosage effect. Furthermore, the present invention relates to the starch with said altered physicochemical properties obtainable from those potato plants as well as to the use of the starch in food and industrial processes. Specifically, the present invention uses the combined dosage effect of the gbssl and the ssIII alleles in order to provide potato starches with novel properties.

BACKGROUND OF THE INVENTION

Globally, there is a growing demand for substituting animal-derived food ingredients, such as gelatin with ingredients obtained from plants. In food industry, starch is of particular interest since it has characteristics similar to gelatin, i.e. both can be used as binding and gelling agents. It can be used for many other purposes, for example as fat replacement in a large variety of food applications, as thickening agent for products like soups, sauces or dairy products, or as stabilizer of oil in water emulsions. As the world’s second most abundant biopolymer, starch does not only serve as food or feed and food or feed ingredient, respectively, but is also directed to other industrial applications such as bioenergy production, or in the paper, textiles and adhesives industries.

The world starch market was estimated to be 48.5 million tons in 2000, with an output value of 20 billion dollars per year. Only about 5% of the global starch supply (2.6 million tons) is obtained from potatoes (European Commission - DG Agriculture, Evaluation of the Community Policy for Starch and Starch Product, 2002, LMC INTERNATIONAL, Oxford, England, pp. 1-12). Potato tuber starch is mainly composed of two polymers - amylopectin and amylose. The different physicochemical properties of these two molecules can require costly processing before the starch is amenable to industrial processes. Since there is a continuing need for the development of starch varieties having altered properties, for example regarding their viscosity and gel transparency and since there is a general need to produce clean label starches with altered properties for various applications in the food, feed, paper, textiles and adhesives industries as well as for the healthcare sector, the object of the present invention is the provision of plants giving rise to starch varieties and the provision of starches derived therefrom.

This problem is solved by the present invention in accordance with the embodiments as characterized in the claims and described further below.

SUMMARY OF THE INVENTION

The present invention generally relates to altered starch producing Solanum plants and starch obtainable from those plants. In particular, the present invention relates to a Solanum plant, plant part, or plant cell comprising at least one inactive allele of at least two endogenous genes encoding enzyme involved in starch synthesis and comprising at least one functional allele of at least one of said at least two genes. Preferably, the enzymes involved in starch synthesis are selected from the group consisting of ADP-glucose pyrophosphorylase (AG- Pase; EC 2.7.7.27), soluble starch synthases (SSs; EC 2.4.1.21), starch branching enzymes (SBEs; EC 2.4.1.18), starch debranching enzymes (DBE; EC 3.2.1.68) and disproportionating enzymes (EC 2.4.1.25). Typically, the presence of the inactive and functional alleles of said at least two genes results in starch that has altered, advantageously improved properties in terms of, for example drying time, gel strength and stability, transparency, viscosity, and/or shape and size of the starch granules compared to starch from a corresponding wild type plant or a plant that has a different allelic background. The Solanum plant, plant part, or plant cell can be, for example a S. tuberosum, i.e. potato plant, plant part, or plant cell.

In one aspect, the present invention features a Solanum plant, plant part, or plant cell, comprising a modified granule bound starch synthase I (GBSSI) allele and at least one further altered soluble starch synthase (SS) allele, the starch obtained from those plants as well as the use of the starch for the production of starch-related products. The present disclosure herein is based at least in part on the observation that potatoes can be obtained, without the use of transgenesis, using combined dosage effect of functional and inactive alleles of the gbssl and the ssIII genes, which give rise to potato starches with novel properties, advantageously improved starch characteristics for particular industrial purposes, as compared to non- modified potatoes and potatoes having single- or multigene knock-outs of enzymes involved in starch synthesis. Potato varieties having such modified starch are also provided. Furthermore, the Solanum plants of the present invention preferably due to single nucleotide mutations in the respective gene which cause the inactive alleles do not carry any foreign DNA and therefore may not be considered by regulatory agencies as a transgenic or genetically modified (GM) crop. Therefore, in a preferred embodiment the plant, plant part, and plant cell of the present invention does not include any exogenous nucleic acid, i.e. nucleic acid molecule which is foreign to the potato plant because of its foreign origin and/or location in the genome of the plant such as conferred by antisense, R Ai, co-suppression, over-expression and trans-dominant mutant approaches used in the prior art.

Hence, the present invention is also based at least in part on the development of inactive alleles of at least two endogenous genes encoding enzyme involved in starch synthesis in potato cultivars by loss-of- function mutations, preferably nucleotide substitutions leading to missense, nonsense or splice site mutations in said genes by chemical mutagenesis and selection or that are created by enzyme assisted gene editing. Importantly, the introduced mutations and alleles, respectively, are stably transferred across the generations, thus giving rise to a new potato which maintain the functional and inactive alleles of said at least two genes encoding enzyme involved in starch synthesis. The cultivated potatoes are normally tetraploid and such potatoes are preferably used for the introduction of the mutations. However, the methods and means disclosed herein are also applicable for potato genotypes of lower or higher ploidy level, e.g. for diploid and hexaploid genotypes. Indeed, though the cultivated forms of potato are vegetatively propagated and are predominantly autotetraploids (2n = 4x = 48), ploidy ranges from diploid to hexaploid in cultivated potato; for a review on potato genetic diversity see, e.g., Machida-Hirano, "Diversity of potato genetic resources" in Breed Sci. 65 (2015), 26-40 and Galvez et al., "Understanding potato with the help of genomics" in AIMS Agriculture and Food 2 (2017), 16-39. There are several methods well known in the art to change the ploidy level of potato cells; see, e.g., Jacobsen et al. Euphytica 53 (1991), 247-253 for the introduction of an amylose-free ( amf) mutant into breeding of cultivated potato, Solanum tuberosum L. and the appended Examples with references cited therein.

Previously, various approaches have been proposed for the manipulation of the starch biosynthetic pathway in plants to obtain starches with altered properties, typically using (simultaneous) antisense inhibition of one or more genes encoding starch synthase iso forms or different starch synthase enzymes; see, e.g., international applications WO 99/066050, WO 2001/019975 and WO 2004/056999. Recently, CRISPR-Cas9 technology has been used in order to produce a full knockout of the gene encoding granule-bound starch synthase (GBSS) in tetraploid potato, i.e. knockout of all four alleles of the GBSS encoding gene; see Andersson et al., Plant Cell Rep. 36 (2017), 117-128 and WO 2017/192095. In this context, it had been observed that one remaining wild type (WT), i.e. functional allele of the GBSS encoding gene was sufficient to maintain enough starch synthase enzyme activity to produce significant amounts of amylose, and thus starch substantially undistinguishable from starch of a wild type plant. These results confirm the previous work of Flipse et al. (Theor. Appl. Genet. 92 (1996), 121-127, who obtained a gene dosage population for nulliplex, simplex, duplex and triplex/quadruplex plants, wherein GBSS activity was significantly different for all groups and showed an almost linear dosage effect for the wildtype GBSS activity but not for amylose content.

Thus, while Andersson and colleagues did not see any allele dosage effect in one, two and three allele mutated lines by phenotypic studies of starch of said mutant plants compared to starch of a wild type plant comprising all four functional alleles of the GBSS gene, the present invention is based on the surprising observation that in case of a potato plant having at least one non- functional allele of a starch synthase encoding gene an allele dosage effect results for any further (multiple) mutated starch synthase allele and vice versa.

Without intending to be bound by theory, it is believed that while one functional allele of a starch synthase gene may be sufficient to do the job within an otherwise wild type background of the other genes involved in the starch synthesis, the presence of inactive alleles in one or more further starch synthase genes and the lack of activity of any one thereof, respectively, has either a direct or indirect effect on the activity, level of expression and/or presence of substrates for the respective starch synthase enzyme(s), thereby leading to starch with substantially altered properties compared to starch from wild type plants and fully knockout mutant lines.

Accordingly, the present invention generally relates to a Solarium plant, plant part, or plant cell comprising at least one inactive allele of the granule-bound starch synthase I gene (gbssl, H) and at least one inactive allele of a further starch synthase gene ( ss ) endogenous to said plant, plant part, or plant cell; and having at least one functional allele of said gbssl and/or ss. Preferably, as illustrated in the Examples one or more, preferably all of the inactive alleles is/are due to a point mutation, in particular a nonsense mutation, leading to an inactive allele in said at least first and/or second endogenous gene. Thus, while in principle any simple mutation such as a nucleotide substitution deletion, duplication or insertion leading to a frameshift, or more complex mutation such as inversion, translocation or transposition in the respective gene may cause the inactive allele, the generation and presence, respectively, of a simple nucleotide substitution in the inactive allele of the gene compared to its functional wild type allele is preferred, which results in a null (activity) and loss-of-fimction, respectively, of the gene or its encoded gene product, for example due to "missense" mutation which changes an amino acid to another amino acid that affects protein function, mostly depending on whether the change is "conservative" or "non-conservative", and what the amino acid actually does; a "silent" mutation which does not change an amino acid, but has a phenotypic effect, e.g., by having a negative impact on gene expression, promoter or enhancer sequences, termination signals, splice donor and acceptor sites or ribosome binding sites; or a "nonsense" mutation which introduces a premature stop codon. Most preferably, the inactive alleles in the said at least two genes involved in starch biosynthesis in the Solanum plant, plant part, or plant cell of the present invention are due to a nonsense mutation and/or missense or silent mutation which affects the splicing of the gene. The advantage of the inactive alleles being due to a (single) point mutation is that otherwise the genotype and genetic background, respectively, of the parent plant which may be of agronomical important traits remains unaffected in kind, avoiding any negative interference effects which may occur in case of more complex mutations and in particular introduction of nucleic acid molecules foreign to the plant.

Thus, in one embodiment the Solanum plant, plant part, or plant cell of the present invention on the genetic level may be identified by determining one or more point mutations, preferably missense, nonsense or silent (affecting the splice site) mutations in at least one, preferably two genes encoding enzymes involved in starch synthesis, e.g., ss genes, which mutation(s) lead to a loss-of- function and inactive allele of said gene(s), wherein said genes are endogenous to the Solanum plant, plant part, or plant cell, and wherein the Solanum plant, plant part, or plant cell comprises at least one functional allele of said at least one or two gene(s). Put in other words, in the Solanum plant, plant part, or plant cell of the present invention the functional, typically wild type allele of the respective gene and inactive allele thereof differ only for said one or more point mutations present in the inactive allele while the remaining nucleotide sequence of the gene remains substantially unaffected in kind and may be identical to that of the functional allele and wild type gene, respectively, or may contain further mutations which however do not affect the expression of the gene or the encoded amino acid sequence and/or the function of the enzyme. Means and methods for determining allelic variants of a gene are known in the art; see also, e.g., BIOPLANT et al., (2005), (2013) and Muth et al., (2008) referred to infra and the Examples.

The Solanum plant, plant part, or plant cell of the present invention can be heterozygous or homozygous for the inactive allele in case of a diploid plant or simplex (1), duplex (2) triplex (3) or quadruplex (4) in case of a tetraploid plant, with the proviso that if the Solanum plant, plant part, or plant cell is homozygous and quadruplex (4), respectively, for an inactive allele of one type of ss gene, it is heterozygous and simplex (1), duplex (2) or triplex (3), respectively for the inactive allele of another ss gene. In a preferred embodiment, the Solanum plant, plant part, or plant cell of the present invention is quadruplex (4) for the inactive allele of gbssl (H4), preferably while being simplex (1), duplex (2) triplex (3) for the inactive allele of ssIII (Pl, P2, P3), or quadruplex (4) for the inactive allele of ssIII (P4), preferably while being quadruplex (4) for inactive allele of ssIII (P4). In a particular preferred embodiment, the Solanum plant, plant part, or plant cell of the present invention has the genotype H4P2 which phenotype may be regarded as a sort of best compromise of producing starch which is translucent as much as possible and preferably also long term stable coming close to starch from H4P4 plants but being less prone to impurities and contamination with fibers that hamper the purification and processing of starch.

Furthermore, regarding most of the analyzed properties, besides the unexpected joint characteristics of starch obtained from H3P4 potato plants (and from H1P4 and H2P4 potato plants too) as well as the H4P2 potato plants the most surprising results have been obtained for starch from the "double intermediate" genotype, i.e. H2P2 potato plants, which most likely will also substantially hold true for starch from other intermediate genotypes, i.e. H1P2, H2P1, H1P3, H3P1, H2P3 and H3P2 potato plants. Thus, though functional alleles of gbssl (H) and ssIII (P) genes - even the same copy number - are present in the plant and should be expected to be dominant over the inactive alleles the properties of the starch obtained from intermediate genotypes such as the H2P2 potato plants is substantially different from starch obtained from wild type H0R0 potato plants. Accordingly, in another preferred embodiment, the Solanum plant, plant part, or plant cell of the present invention has an "intermediate" genotype, most preferably H4P2.

In case of duplex (2) triplex (3) or quadruplex (4) genotype the mutation for each inactive allele may be the same and/or different. In a particular preferred embodiment, inactive alleles in the said at least two genes in the Solanum plant, plant part, or plant cell comprise the mutations described and illustrated in the Examples.

Thus, in one preferred embodiment, the Solanum plant, plant part, or plant cell of the present invention comprises an inactive allele of gbssl is due to at least one mutation in the gbssl sequence (accession number X58453), preferably at nucleotide position G1372, preferably G- >A [Clone E433] leading to an amino acid substitution in the amino acid sequence of GBSSI (accession number Q00775) at position GlylOO to Asp and/or nucleotide position G1407, preferably G->A [Clone El 100] leading to mis-splicing of the primary transcript. In addition, or alternatively the Solanum plant, plant part, or plant cell of the present invention comprises an inactive allele of ssIII is due to at least one mutation in the cDNA ssIII sequence (accession number X95759), preferably at nucleotide position G1849, preferably G->A [Clone R148] leading to conversion of codon TGG (Trp569 in the amino acid sequence of SSIII (accession number CAA64173) into the stop codon TGA; and/or nucleotide position C2144, preferably a C->T transition [Clone B309] leading to conversion of codon CAG (Gln668 in the amino acid sequence of SSIII (accession number CAA64173) into the stop codon TAG.

Preferably, the starch obtainable from said plant, plant part, or plant cell is altered in its physicochemical parameters such as those disclosed below and illustrated in the Examples, compared to starch obtainable form a control Solanum plant, plant part, or plant cell that lacks said alleles, i.e. a wild type plant or a plant having full knock-outs of any of the ss genes only or which are nulliplex, simplex, duplex or triplex/quadruplex for one ss gene while having only functional alleles of the other ss genes. Examples of important functional characteristics and physicochemical properties, respectively, are (apparent) amylose content, gel transparency, phosphate content, the solubility, the gelatinization behavior, the size and form/shape of the granules, granule swelling behavior, the water binding capability, the viscosity and texture properties, the retrogradation property, the film forming properties, the freeze/thaw stability and the long term stability, etc.

As described in the appended Examples and shown in the Figures, in accordance with the present invention potato plants are provided that are quadruplex (4) for the inactive allele of gbssl (H4) and simplex (1), duplex (2) or triplex (3) for the inactive allele of ssIII (Pl, P2, P3); quadruplex (4) for the inactive allele of ssIII (P4) and simplex (1), duplex (2) or triplex (3) for the inactive allele of gbssl (Hl, H2, H3); or duplex (2) for the inactive allele of gbssl (H2) and duplex (2) for the inactive allele of ss, preferably ssIII (P2) and that produce starch with unique properties compared to the parental potato that it is derived from and which are significantly different compared with commercially available potato starches. Preferably, the starch obtainable from the Solanum plant, plant part, or plant cell of the present invention is characterized in that

(i) starch as obtainable from a H4P1, H4P2 or H4P3 potato plant has

(al) an apparent amylose content which is lower in comparison to the apparent amylose content of starch derived from a H0R0 potato plant and higher in comparison to the apparent amylose content of starch derived from a H4P4 potato plant, wherein the apparent amylose content is between about -0.5% and 2%, in particular between about 1.0% and 1.5% [H4P1], 0% and 1% [H4P2] or -0.5% and 2% [H4P3] in comparison to 11% to 18% of starch derived from a H0R0 potato plant and to -1% to -3% of starch derived from a H4P4 potato plant;

(bl) a viscosity onset temperature which is higher in comparison to the viscosity onset temperature of starch derived from a H0R0 and a H4P4 potato plant, wherein the viscosity onset temperature is between about 64°C and 69°C, in particular between about 66°C and 67°C [H4P1], 64°C and 66°C [H4P2] or 64°C and 69°C [H4P3] in comparison to 60°C to 64°C of starch derived from a H0R0 and a H4P4 potato plant;

(cl) a gel transparency which is in average higher in comparison to the gel transparency of starch derived from a H0R0 and a H4P0 potato plant and lower in comparison to the gel transparency of a starch derived from a H4P4 potato plant, wherein the transmission of the gel is between about 38% and 47% [H4P1], 46% and 62% [H4P2] or 48% and 73% [H4P3] in comparison to between 0.5% to 1.5% and 23% to 42% of starch derived from a H0R0 potato plant and a H4P0 potato plant, respectively, and to 61% to 72% of starch derived from a H4P4 potato plant;

(dl) a long term gel stability which is higher in comparison to the stability of a starch gel derived from a H0R0 potato plant, wherein the difference in the storage modulus being measured during the shearing of the starch gel, which is calculated via subtracting the storage modulus measured directly after cooking of the starch gel from the storage modulus measured after storage for three weeks at 5°C, is between about -1.5 Pa and 3 Pa [H4P1, H4P2, H4P3] in comparison to 35 Pa to 110 Pa as determined for the starch gel derived from a H0R0 plant;

(el) an average relative particle size (d50) which is in average lower in comparison to the relative particle size of starch derived from a H0R0 and a H4P0 potato plant and higher in comparison to the average particle size of a starch derived from a H4P4 potato plant, wherein the particle size is between about 43 pm and 49 pm [H4P1 and H4P2] or 36 pm and 45 pm [H4P3] in comparison to 49 pm to 55 pm and 49 pm to 62 pm of starch derived from a H0R0 potato plant and a H4P0 potato plant, respectively, and to 25 pm to 37 pm of starch derived from a H4P4 potato plant, and/or the starch granules show a form of any of the [HP] genotypes as show in Figure 5, preferably the starch granules show a form and/or pattern of differential volume of starch granules of [H4P2] as show in Figures 5 to 7; and/or (fl ) a phosphate content which is lower in comparison to the phosphate content of starch derived from a H4P4 potato plant, wherein the phosphate content is between about 850 ppm and 1000 ppm [H4P1], 700 ppm and 1100 ppm [H4P2] or 550 ppm and 1100 ppm [H4P3] in comparison to about 950 ppm to 1350 ppm of starch derived from a H4P4 potato plant,

(ii) starch as obtainable from a H1P4, H2P4 or H3P4 plant has

(a2) an apparent amylose content which is higher in comparison to the apparent amylose content of starch derived from a H4P4 and/or a H4P0 potato plant and preferably lower than of starch derived from H0P4, wherein the apparent amylose content is between about 16,5% and 20,5% [H1P4], 16% and 20% [H2P4], 11% and 16% [H3P4] in comparison to -1% to -3% of starch derived from a H4P4 and to 0% to 3% of starch derived from a H4P0 and/or to 18% to 20% of starch derived from a H0P4 potato plant;

(b2) a viscosity onset temperature which is lower in comparison to the viscosity onset temperature of starch derived from a H0R0, H4P0 and/or H4P4 potato plant, wherein the viscosity onset temperature is between 57°C and 60°C in comparison to 60°C to 64°C of starch derived from a H0R0 and a H4P4 potato plant and to 64°C to 69°C of starch derived from a H4P0 potato plant,

(c2) a gel transparency which is lower in comparison to the gel transparency of starch derived from a H4P0 and/or a H4P4 potato plant, wherein the transmission of the gel is between about 1% and 2% in comparison to 23% to 42% and 61% to 72% of starch derived from a H4P0 potato plant and a H4P4 potato plant, respectively; (d2) a long term gel stability which is lower in comparison to the stability of a starch gel derived from a H4P0 and/or a H4P4 potato plant, wherein the difference in the storage modulus being measured during the shearing of the starch gel, which is calculated via subtracting the storage modulus measured directly after cooking of the starch gel from the storage modulus measured after storage for three weeks at 5°C, is between about 55 Pa and 165 Pa in comparison to about -1 Pa to 5 Pa as determined for the starch gel derived from a H4P0 and/or to about -1.5 Pa to 2 Pa as determined for the starch gel derived from a H4P4 potato plant;

(e2) starch granules having an average relative particle size (d50) which is in average lower in comparison to the relative particle size of starch derived from a H0R0 and a H4P0 potato plant and higher in comparison to the average particle size of a starch derived from a H4P4 potato plant, wherein the particle size is between about 30 pm and 39 pm in comparison to 49 pm to 55 pm and 49 pm to 62 pm of starch derived from a H0R0 potato plant and a H4P0 potato plant, respectively, and to 25 pm to 37 pm of starch derived from a H4P4 potato plant, and said granules having fissures, and/or the starch granules show a form of starch granules of [H3P4] as shown in Figure 5; and/or

(f2) a phosphate content which is higher in comparison to the phosphate content of starch derived from a H4P0 potato plant, wherein the phosphate content is between about 950 ppm and 1300 ppm in comparison to about 500 ppm to 950 ppm of starch derived from a H4P0 potato plant, or

(iii) being obtainable from a H2P2 potato plant, preferably having

(a2) an apparent amylose content which is higher in comparison to the apparent amylose content of starch derived from a H4P4 and/or H4P0 potato plant and preferably lower than of starch derived from H0P4, wherein the apparent amylose content is between about 15% and 18% in comparison to -1% to -3% of starch derived from a H4P4, 0% to 3% of starch derived from a H4P0 and/or to 18% to 20% of starch derived from a H0P4 potato plant;

(b2) a viscosity onset temperature which is higher in comparison to the viscosity onset temperature of starch derived from a H0R0 and/or H0P4 potato plant, wherein the viscosity onset temperature is between about 65,5°C and 68,5°C in comparison to 60°C to 64°C of starch derived from a H0R0 and/or 62°C to 64,5°C of starch derived from a H0P4 potato plant,

(c2) a gel transparency which is lower in comparison to the gel transparency of starch derived from a H4P0, H4P4 and/or a H0P4 potato plant, wherein the transmission of the gel is between about 0,25% and 1,25% in comparison to 23% to 42% and 61% to 72% of starch derived from a H4P0 potato plant and a H4P4 potato plant, respectively, and 1,0% to 3,0% of starch derived from a H0P4 potato plant;

(d2) an average long term gel stability which is lower in comparison to the stability of a starch gel derived from a H4P0 and/or a H4P4 potato plant, wherein the difference in the storage modulus being measured during the shearing of the starch gel is between about 200 Pa and 300 Pa in comparison to -1 Pa to 5 Pa as determined for the starch gel derived from a H4P0 and/or to -1.5 Pa to 2 Pa as determined for the starch gel derived from a H4P4 potato plant;

(e2) starch granules having an average relative particle size (d50) which is in average lower in comparison to the relative particle size of starch derived from a H0R0 and a H4P0 potato plant and/or higher in comparison to the relative particle size of starch derived from a H4P4 potato plant, wherein the particle size is between about 25 pm and 43 pm in comparison to 49 pm to 55 pm and 49 pm to 62 pm of starch derived from a H0R0 potato plant and a H4P0 potato plant, respectively, and 25 pm to 37 pm of starch derived from a H4P4 potato plant, wherein said granules having substantially no fissures; and/or

(f2) a phosphate content which is lower in comparison to the phosphate content of starch derived from a H0R0, H0P4 and/or a H4P4 potato plant, wherein the phosphate content is between about 700 ppm and 1000 ppm in comparison to about 800 ppm to 1200 ppm of starch derived from a H0R0 potato plant, 500 ppm to 950 ppm of starch derived from a H4P0 potato plant and 1200 ppm to 1500 ppm of starch derived from a H0P4 potato plant,

wherein (a) the apparent amylose content has been determined by the method of Hovenkamp- Hermelink et al, Potato Research 31 (1988), 241-246;

(b) the viscosity onset temperature has been determined by visco metric analysis of a 4% (w/w) aqueous suspension of starch using a Brabender Viscograph-E with the following program: Start temperature 25°C and 350 cmg, heating up with l.5°C/min to 95°C and hold for 30 min, cool down to 25°C;

(c) the gel transparency has been determined via measuring the transmission of a 4% (w/w) viscosity solution of the starch after cooling at 4°C for 14 days at 655 nm using a Photometer DR 6000 of HACH Lange;

(d) the long term stability has been determined of a 4% (w/w) viscosity solution of starch using the rheometer MCR 301 of Anton Paar GmbH, wherein G’ was noted at 1.007 Hz;

(e) the particle size, form and differential volume of the starch granules may differ in terms of being substantially globular- and spherical- shaped; bimodal, oval- or egg-shaped; smooth or with fissures as shown in Figures 5 to 7;

(f) the phosphate content has been determined via analysis of a sample containing 0.5 g starch, 6.0 ml distilled water and 3.0 ml 65% nitric acid that has been digested using the Multiwave Go of Anton Paar GmbH using the ICPE 9000 of Shimazu.

Thus, in one preferred aspect the present invention relates to tetraploid potato plants having at least one inactive allele of the granule-bound starch synthase I gene ( gbssJ H) and the soluble starch synthase gene ( ssIII , P) and at least one functional allele of gbssl and/or ssIH, and the starch obtainable from those potato plants, wherein the starch is preferably characterized by one or more of the above-recited physicochemical parameters (al) to (fl) or (a2) to (f2), preferably by two, more preferably three, most preferably four and advantageously all five or six parameters, i.e. one or any suitable combination of parameters which is sufficient to distinguish the given type of starch obtainable from the Solanum plant, plant part, or plant cell of the present invention from starch provided by the mentioned control or reference plant, plant part, or plant cell or any other starch provided and described in the prior art. Needless to say that the physicochemical parameters (al) to (fl) are typically selected in accordance with their presence for the type of starch for each of the described [HP] genotypes, i.e. the physicochemical parameters (al) to (fl) of H4P1 may be combined, of H4P2, etc. However, in some embodiments it may be desired to combine characteristics of different types of starch for certain applications, for example by mixing different types of starch after extraction or by co-extraction of starch from two or more different HP plants. Therefore, one embodiment of the present invention relates to starch which may have one or more physicochemical parameter (al) to (fl ) and (a2) to (f2) of one or more [HP] genotypes and/or intermediate physicochemical parameters which result from such combination, preferably wherein the starch obtained or obtainable from said combination of different starch types and from [HP] plants, respectively, is still different in the mentioned physicochemical parameters from starch disclosed in the prior art; see also supra and the Examples.

In a further aspect the present invention relates to a method of making starch or a derivative thereof, the method comprising the step of extracting the starch content from the Solarium plant, plant part, or plant cell of the present invention, preferably wherein the plant part is a potato tuber. The method may further comprise the step of modifying the extracted starch by physical, enzymatic and/or chemical processing in vitro.

In addition, the present invention relates to starch obtainable from a Solanum plant, plant part, or plant cell of the present invention, preferably wherein potato tuber or by the method of the present invention. Preferably, the starch is characterized by one or more of the above-recited physicochemical parameters (al) to (W) or (a2) to (f2), preferably by two, more preferably three, most preferably four and advantageously all five or six parameters, i.e. one or any suitable combination of parameters which is sufficient to distinguish the given type of starch obtainable from the Solanum plant, plant part, or plant cell of the present invention from starch provided by the mentioned control or reference plant, plant part, or plant cell or any other starch provided and described in the prior art. The changes in H- and P allele dosages and resulting effect on starch characteristics like on amylose content and other starch characteristics for potato plants of the present invention with different allele dosages (nulliplex to quadruplex) of inactive gfrv.s7-allclcs (H) and/or .v.s7//-allclcs (P), i.e., potato plants which are quadruplex (4) for the inactive allele of gbssl (H4) and simplex (1), duplex (2) or triplex (3) for the inactive allele of ssIII (Pl, P2, P3) and plants which are quadruplex (4) for the inactive allele of ssIII (P4) and simplex (1), duplex (2) or triplex (3) for the inactive allele of gbssl (Hl, H2, H3); or duplex (2) for the inactive allele of gbssl (H2) and duplex (2) for the inactive allele of ssIII (P2) vis-d-vis wild type plants and plants which are quadruplex for inactive g/rv.s7-allclcs (H4) and/or s.s///-al lclcs (P4) are summarized in Example 10 and illustrated Figures 5, 8 and 9 and explained in the legends thereto, the disclosure content of which form preferred embodiments of the present invention. In a further aspect the present invention relates to a method of producing a starch based or starch containing product comprising the method and the use of the starch of the present invention, respectively, and to such starch based or starch containing products comprising starch of the present invention. In still another aspect the present invention refers to different uses of said starch or starch based or starch containing product for applications in the food, feed, paper, textiles and adhesives industries, for bioenergy production, and as additives for pharmaceutical and personal care products.

Hence, the present invention generally relates to the use of Solanum plants comprising at least one inactive allele of a gene endogenous to said plant, said gene encoding an enzyme involved in starch synthesis for the generation of a plant, plant part, or plant cell disclosed herein and for the production of novel starch types, preferably such as characterized by the physicochemical parameters recited above and illustrated in the appended Examples, respectively, and uses thereof.

The different aspects of the present invention also appear in the independent claims, and further embodiments are disclosed in the accompanying dependent claims.

BRIEF DESCRIPTION OF THE FIGURES

The embodiments of the present invention are described with reference to the attached Figures and sequences.

Fig· 1 : Schematical intron-exon structure of the ssIII gene of Solanum tubersosum including a table indicating the number of stop codons that could be generated via EMS treatment.

Fig. 2: Alignment of the 1.8 kbp fragment of the ssIII gene of Solanum tuberosum sequenced in accordance with the present invention (consensus H16/H69; SEQ ID NO: 1), the corresponding 1.8 kbp fragment of the genomic sequence of the ssIII gene of Solanum tuberosum which is publicly available (scaffold00099, JH137887) and the corresponding 1.8 kbp fragment of the cDNA of the ssIII gene of Solanum tuberosum set forth under accession number X95759 of the DDBJ Nucleotide Sequence Database. Furthermore, the null alleles which have been identified in accordance with the present invention are highlighted. In particular, clones have been identified where the C at position 2144 is substituted with T (B309), G at positon 1849 is substituted with A (R148), G at position 1672 is substituted with A (GR457), and G at position 1897 is substituted with A (R721).

Fig. 3: Simplified breeding scheme for the generation of potato plants having inactive ssIII and gbssl alleles. Level 1: The genotypes of diploid and tetraploid clones are shown for the breeding starting with diploid clones with an inactive allele of the .v.s7//-gcnc (s; denomination B309 or R148). Level 2: After doubling of the genome, the clones were crossed with HAP clones being homozygous for the inactive gbssl gene (g; denomination E433 or El 100). Level 3: Clones being duplex for inactive g and duplex for inactive s alleles originating from different parental clones are intercrossed. Level 4: Wanted phenotypes can be found although clones being homozygous for both inactive alleles are very rare (1 :1.296). When inter-crossing level 3- and level 4-genotypes the additional genotypes of Level 5 can be selected. The genotypes were bred in two subsequent steps. Consequently, the genotypes of tier 5, namely H2P4, H1P4, and H0P4 and the respective controls were grown in the greenhouse whereas the other genotypes were already grown in the field.

Fig. 4: Properties of starches derived from potato plants which are quadruplex for the inactive allele of gbssl and in addition having one, two, or three inactive alleles of ssIH, in particular from plants which are H4P1, H4P2, H4P3 compared to starches derived from potato plants which are quadruplex for the inactive allele of gbssl and nulliplex and/or quadruplex for the inactive allele of ssIII (H4P0, H4P4). A) diagram plotting the apparent amylose content as determined by the method of Hovenkamp- Hermelink; B) and C) box plots depicting the viscosity onset temperature and peak temperature as determined via viscosity measurements of 4% starch suspensions using the Viscograph-E of Brabender; D) diagram plotting the gel transparency as determined by measuring the transmission of starch gels at 655 nm after 14 days; E) diagram plotting the particle size of starch grains: F) diagram plotting the relative phosphate content as determined via analysis of a sample containing 0.5 g starch, 6.0 ml distilled water and 3.0 ml 65% nitric acid that has been digested using the Multiwave Go of Anton Paar GmbH using the ICPE 9000 of Shimazu. The mean value of the phosphate content of starch derived from a H0R0 potato plant was set to 100%; G) diagram plotting the difference in the storage modulus being measured during the shearing of starch gels obtained from 4% starch solutions, which is calculated via subtracting the storage modulus measured directly after cooking of the starch gels from the storage modulus measured after storage of the starch gels for three weeks at 5°C. For the measurements the rheometer MCR 301 of Anton Paar GmbH was used, wherein G’ was noted at 1.007 Hz. The storage modulus G' [Pa] describes the elastic properties of the starch solution/starch (Mezger, The Rheology Handbook, 3rd revised edition Hanover: Vincentz Network (2011)).

Fig. 5 : Size and shape of starch granules derived from potato plants which are quadruplex for the inactive allele of gbssl and in addition having one, two, or three inactive alleles of ssIH, in particular from plants which are H4P1, H4P2, H4P3 and of starch granules derived from potato plants which are H3 for the inactive allele of gbssl and having four inactive alleles of ssIII (H3P4) compared to starch granules derived from potato plants which are nulliplex for the inactive allele of gbssl and ssIII (H0R0) and from potato plants which are quadruplex for the inactive allele of gbssl and nulliplex and/or quadruplex for the inactive allele of ssIII (H4P0, H4P4). A) diagram plotting the ratio of the shape index of the starch granules, wherein 1 corresponds to round granules and 1.5 corresponds to oval granules; B) microscopic picture of starch granules: Upper row from left to right: H4P0, H4P1, H4P2; Lower row from left to right: H4P3, H4P4, H3P4 (length of the shortest square is 50mhi); C) Close up picture of starch granules derived from H3P4 potato plants. The microscopic pictures have been taken from starch granules derived from freshly cut potatoes; D) microscopic picture of starch granules: From left to right: H4P4, H2P4, H0P4, H2P2 (length of the shortest square in the lower row is 50mhi.

Fig. 6: Microscopic picture of a mixture of starch granules derived from a potato plant which is quadruplex for the inactive allele of gbssl and duplex for the inactive allele of ssIII (H4P2) and from a potato plant which is nulliplex for the inactive alleles of gbssl and ssIII (H0R0). Starch granules have been stained with Lugol's solution

Fig. 7: Analysis of the size distribution and purity of starch grains derived from a potato plant which is quadruplex for the inactive alleles of gbssl and ssIII (H4P4) (upper diagram) and from a potato plant which is quadruplex for the inactive allele of gbssl and duplex for the inactive allele of ssIII (H4P2) (lower diagram) using the Laser Diffraction Particle Size Analyzer LS 13 320 of Beckman Coulter GmbH. The particles having a diameter ranging from about 100 to 600 mM represent impurities, e.g., fibers that could not be washed out during purification.

Fig. 8: Viscogram (Viscograph-E of Brabender) of 4% starch suspensions derived from potato plants which A are quadruplex or nulliplex for the inactive alleles of gbssl and ssIII (H4P4, H0R0), quadruplex for the inactive allele of gbssl and duplex or nulliplex for the inactive allele of ssIII (H4P2, H4P0) and triplex for the inactive allele of gbssl and quadruplex for the inactive allele of ssIII (H3P4); and B are quadruplex for the inactive alleles of gbssl and ssIII (H4P4), nulliplex, simplex, duplex or triplex for the inactive allele gbssl and quadruplex for the inactive allele of ssIII (H0P4, H1P4, H2P4, H3P4) and duplex for the inactive allele of gbssl and ssIII (H2P2). The straight line forming a trapeze represents the temperature profile.

Fig. 9: Changes in H- and P allele dosages and effect on amylose content and other starch characteristics. Plants with different allele dosages ( nulliplex to quadruplex ) of inactive gfiv.s7-allclcs (H) and/or .v.s7//-allclcs (P) were grown in the field (H0R0, H4P0 up to H3P4) or in the greenhouse (H3P4 to H0P4 and H2P2) and starches were analyzed as described. The mean values for clones being homoygous for inactive if/>.vs7-alleles (H4) are symbolized by black symbols and those being homozygous for inactive \\///-alleles (P4) are shown by grey triangles. The controls H0R0 and H2P2 are depicted as circles. Genotypes of the analyzed groups concerning the inactive gbssl- and v.s///-al lclcs are given at the bottom of the picture. Data for starches isolated from the genotypes H4P4 and H3P4 were generated from both origins (field and GH). Due to cultivation differences in the field (plants grown from tubers) and in the greenhouse (tissue culture plants transferred to greenhouse, limited volume of cultivation pots) the results may differ as can be seen in this“overlap” region. The correlation of allele dosages with different specific starch characteristics is represented in the following pictures. Scaling and measured characteristics are given: (A) apparent amylose content (% amylose); (B) long term stability of starch gels (Pa); (C) phosphate (ppm); (D) viscosity onset temperature (°C); (E) light transmission of starch gels after 14 days (%); (F) particle size d50 (mhi). DEFINITIONS

Initially, some of the terms used throughout the specification are defined in the following.

Unless otherwise stated, a "plant" of the present invention is any plant of the genus Solanum, in particular Solanum tuberosum. The term "potato" is understood to mean any potato plant belonging to the species Solanum tuberosum. As used herein, the terms "plant" and "plant part" means any complete or partial plant, single cells and cell tissues such as plant cells that are intact in plants, cell clumps and tissue cultures from which potato plants can be regenerated. Examples of plant parts include, but are not limited to, single cells and tissues from pollen, ovules, leaves, embryos, roots, root tips, anthers, flowers, fruits, stems shoots, tubers, including potato tubers for consumption or 'seed tubers' for cultivation or clonal propagation, and seeds; as well as pollen, ovules, leaves, embryos, roots, root tips, anthers, flowers, fruits, stems, shoots, scions, rootstocks, seeds, protoplasts, calli, and the like. For the purpose of obtaining starch in accordance with the present invention the term "plant part" preferably refers to a tuber and potato tuber, respectively.

The term "allele(s)" means any of one or more alternative forms of a gene at a particular locus. In a diploid (or amphidiploid) cell of an organism, alleles of a given gene are located at a specific location or locus on a chromosome, with one allele being present on each chromosome of the pair of homologous chromosomes. Similarly, in a tetraploid cell of an organism, one allele is present on each chromosome of the group of four homologous chromosomes. "Heterozygous" alleles are different alleles residing at a specific locus, positioned individually on corresponding homologous chromosomes. "Homozygous" alleles are identical alleles residing at a specific locus, positioned individually on corresponding homologous chromosomes in the cell.

The term "apparent amylose content" describes the binding of iodine molecules to helical structures being present in amylose molecules (synthesized by GBSSI) and long side chains (DP > 60) of the amylopectin molecule (synthesized by SSIII) (Chen and Bergmann, Carbohydrate Polymers 69 (2007), 562-578.

"Wild type" as used herein refers to a typical form of a plant or a gene as it most commonly occurs in nature. A "wild type (gene) allele" is a naturally occurring gene allele ( e.g ., as found within naturally occurring S. tuberosum plants) that encodes a functional protein, while an "inactive allele" is a gene allele that does not encode a functional protein. Such a "non functional mutant gene allele" can include one or more mutations in its nucleic acid sequence, where the mutation(s) result in a reduced or even no detectable amount of functional protein encoded by the gene in the plant, plant part or plant cell in vivo.

As used herein, the term "population" means a genetically heterogeneous collection of plants sharing a common genetic derivation.

As used herein, the term "variety" is as defined in the UPOV treaty and refers to any plant grouping within a single botanical taxon of the lowest known rank, which grouping can be: (a) defined by the expression of the characteristics that results from a given genotype or combination of genotypes, (b) distinguished from any other plant grouping by the expression of at least one of the said characteristics, and (c) considered as a unit with regard to its suitability for being propagated unchanged.

The term "cultivar" (for cultivated variety) as used herein is defined as a variety that is not normally found in nature but that has been cultivated by humans, i.e. having a biological status other than a "wild" status, which "wild" status indicates the original non-cultivated, or natural state of a plant or accession. The term "cultivar" specifically relates to a potato plant having a ploidy level that is tetraploid. The term "cultivar" further includes, but is not limited to, semi-natural, semi-wild, weedy, traditional cultivar, landrace, breeding material, research material, breeder's line, synthetic population, hybrid, founder stock/base population, inbred line (parent of hybrid cultivar), segregating population, mutant/genetic stock, and advanced/improved cultivar.

As used herein, and confined to tetraploids, the term "nulliplex", "simplex", "duplex", "triplex" and "quadruplex", is defined as a genetic condition existing when an inactive allele at a corresponding locus on corresponding homologous chromosomes is present 0, 1, 2, 3 or 4 times, respectively. The term "dosage" when used in relation to an allele means the amount of alleles present in the genotype of the plant. For the purpose of the present invention, in case of plants having no functional allele of the respective starch synthase gene, e.g., plants lacking GBSSI activity due to the presence of inactive alleles of gbssl (H) only, i.e. being quadruplex (H4) for tetraploid potato the feature being homozygous or quadruplex for the "inactive allele" may also include other means and conditions which bring about the same effect, e.g., plants lacking GBSSI activity due to, for example, the expression of antisense RNA or RNAi; see, e.g. Kuipers et al., Plant Mol. Biol. 26 (1994), 1759-1773; Visser et al., Mol. Gen. Genet. 225 (1991), 289-296; and Andersson et al., Plant Cell Rep. 22 (2003), 261-267 2003) as well as the international applications cited supra. Furthermore, it is prudent to expect that diploid Solanum plants which are heterozygous (i.e. simplex (1)) for an inactive and functional allele of gene(s) involved in starch biosynthesis as explained above produce substantially the same type of (altered) starch as a corresponding tetraploid plant which is duplex (2) for said allele(s). Likewise, a hexaploid Solanum plant which is triplex (3) for an inactive and functional allele of said gene(s) may produce substantially the same type of (altered) starch as a corresponding tetraploid plant which is duplex (2) for said allele(s). Accordingly, unless stated otherwise the description and claims on tetraploid potato plants and their use is equally applicable on diploid and hexaploid plants and encompassed by the present invention.

The term "SS" and "ss" refers to starch synthases and their encoding genes, respectively, which are involved in starch synthesis in Solanum, in particular potato ( Solanum tuberosum). Enzymes involved in starch synthesis are known in the art (see for review, e.g., Zhang et al., Starch/Starke 69 (2017) 1600194 and Nazarian-Firouzabadia and Visser, Biochemistry and Biophysics Reports 10 (2017), 7-16), including ADP-glucose pyrophosphorylase (AG- Pase; EC 2.7.7.27), soluble starch synthases (SSs; EC 2.4.1.21), starch branching enzymes (SBEs; EC 2.4.1.18), starch debranching enzymes (DBE; EC 3.2.1.68) and disproportionating enzymes (EC 2.4.1.25). Various SSs are involved in the elongation of the glucan chains by transferring glucose residues from ADP-glucose to the non-reducing end of the growing glucan chains. SBEs introduce the a-l,6 linkages by simultaneous cleavage of some short a- 1,4 linked glucan chains and connecting them to other chains, thus providing amylopectin molecules as well as increasing the number of non-reducing ends for further elongation by various SSs isoforms. DBEs seem to trim the irregularly arranged glucan chains to maintain glucan branches in amylopectin molecules in a regular order, thus enabling formation of semi crystalline structures. Disproportionating enzymes cleave short malto-oligosaccharides (MOS) producing glucose units which can either be used for the ADP-glucose synthesis or as an energy source for plant metabolism. SSs in higher plants possess multiple iso forms which are grouped based on their amino acid sequence similarities. All the SSs appear to share the same overall structure, consisting of a glass domain (substrate-binding site), a typical transit peptide and different motifs. SSs are further classified into three distinctly localized groups in the plastids, i.e., exclusively granule-bounded (Granular-Bound Starch Synthase, GBSS) exclusive or nearly exclusive activity in the soluble phase; and those present in both the granule and soluble phase. Moreover, in potato SSs are further subdivided into four subclasses based upon cDNA and amino acid sequence similarities, i.e. GBSS (-60 kDa), SSI (-57 kDa), SSII (-77 kDa), and SSIII (-110-140 kDa) while an enzyme similar to any known SSIV has not been reported/or characterized in potato. The term "GBSSI" is to be understood to mean any enzyme that belongs to the class of starch granule-bound starch synthases of the isoform I. Consequently, the term " gbssl gene" means a nucleic acid molecule or polynucleotide (DNA, cDNA) that codes for GBSSI.

It is known that plants can be genetically modified in such a way that they produce starches that can be differentiated from the starch in the corresponding non-genetically modified plant from which they have been manufactured on the basis of physicochemical parameters. Potato plants in which the expression and/or activity of the starch granule-bound starch synthase 1 (GBSSI), SSII, SSIII and/or DBE (also denoted 'ΈEG') have been reduced and eliminated, respectively, are described and reviewed in international application WO2017/192095; see, e.g., page 7, line 11 to page 10, line 5 as well the Examples and Figures disclosed therein.

The term "SSIII" means any enzyme that belongs to the class of soluble starch synthases of the iso form III. Soluble starch synthases catalyze a glycosylation reaction in which glucose moieties of the ADP-glucose substrate are transferred to an a-l,4-linked glucan chain with formation of new a- 1, 4-linkages, wherein the different classes synthesize chains of different lengths. For example, SSIIIs are described by Marshall et al., The Plant Cell 8 (1996), 1121- 1135; Li et al., Plant Physiology 123 (2000), 613-624; Abel et al., The Plant Journal 10 (1996), 981-991 and in WO 00/66745.

The term " ssIII gene" is to be understood to mean a nucleic acid molecule or polynucleotide (DNA, cDNA) that codes for SSIII. Polynucleotides coding for soluble starch synthases have been described for various plant species. For potato it is disclosed in Abel et al., The Plant Journal 10 (1996), 981-991. The term "ssIII gene" preferably means a nucleic acid molecule or polynucleotide (cDNA, DNA) that codes for SSIII in potato plants.

The "size", "form" and "shape" of starch granules from plants including potato are well known and are summarized, e.g., in Molenda et al., Pol. J. Food Nutr. Sci. 15/56 (2006), 161— 168, describing the microstructure and mechanical parameters of five types of starch including potato and methods of the determination of such parameters. According to the size of individual granules, starches may be grouped into four classes following Lindeboom et al., "Analytical, biochemical and physicochemical aspects of granule size, with emphasis on small granule starches: A review." Starch 56 (2004), 89-99, i.e. : [2004]: large - above 25 pm, medium - from 10 to 25 pm, small - from 5 to 10 pm, and very small - below 5 pm. In some cases, bimodal size distribution (predominantly small and large granules) is observed. Granules of potato starch belong to the first class, most of cereal starches show bimodal size, oat, buckwheat, rice millet represent the class of small starch. Starches of very small granules are obtained, among others, from amaranth, taro, quinoa, or cow cockle. Considering their morphology, starch granules may be classified as oval, oblong, spherical, polygonal, irregular or lens-shaped. The size distribution of granules in a specimen may be the main factor responsible for properties of starch in bulk (aggregation, clustering) that influence its behaviour during transportation and storage, which in turn may affect the quality of the product. Granules of potato starch belong to the class of large and are clearly bimodal, which may result in unusual behavior during compression; see Figure 4a of Molenda et al. (2006). The largest granules with diameter of nearly 60 11 m are oval, round or irregular. Furthermore, it has been observed that starch granules in genetically modified, high amylose potatoes are very small (27 pm to 32 pm) compared to granules in potatoes with high or normal amylopectin contents (46 pm to 56 pm); see Karlsson et al., Food Chemistry 100 (2007), 136-146. In addition, the starch in high amylose potatoes had a shape resembling that of normal starch granules; however, the surface was irregular and many of the granules possessed asymmetrical fissures.

DETAILED DESCRIPTION OF THE INVENTION

The present invention generally relates to altered starch producing Solanum plants and starch obtainable from those plants. In particular, the present invention relates to a Solanum plant, plant part, or plant cell comprising at least one inactive allele of at least two endogenous genes encoding enzyme involved in starch synthesis and comprising at least one functional allele of at least one of said at least two genes, preferably wherein the enzymes involved in starch synthesis are soluble starch synthases. Typically, the presence of the inactive and functional alleles of said at least two genes, i.e. the dosage of functional and inactive alleles of the said at least two genes results in starch that has altered, advantageously improved properties in terms of, for example drying time, gel strength and stability, transparency, viscosity, and/or shape and size of the starch granules compared to starch from a corresponding wild type plant or a plant that has a different allelic background. The Solanum plant, plant part, or plant cell can be, for example a S. tuberosum, i.e. potato plant, plant part, or plant cell. In particular, as illustrated in the Examples the present invention provides potato plants having at least one inactive allele of the granule-bound starch synthase I gene (gbssl, H) and the soluble starch synthase gene ( ssIII , P) and at least one functional allele of gbssl and/or ssIH, the starch obtained from those potato plants as well as the use of the starch. Specifically, the combined dosage effect of the gbssl and the ssIII alleles in order to provide potato starches with novel properties is described.

Accordingly, while generally applicable to Solanum plants, plant parts, or plant cells and encompassed by the present invention, the following embodiments are described by reference to the allele dosage effect of inactive and functional alleles of gbssl and ssIII in potato plants.

In the stem-home potato tubers starch is stored in starch granules being much larger than those in cereal endosperms and the potato starch further contains negligible lipids, less protein than cereal granules and has a comparable high phosphorous content (Ellis et al, Journal of the Science of Food and Agriculture 77 (1998), 289-311). Thus, potato starches are of particular interest for various applications in industry. It is known that changing the ratio of the two components amylose and amylopectin greatly alters the properties of the starch. In this context, one single enzyme was found to be responsible for the synthesis of amylose, i.e. granule-bound starch synthase (GBSS). In potato, the GBSS enzyme is encoded by a single locus (GBSSI) having four alleles in the cultivated potato. The inactivation of the gbssl gene by silencing of the gene function through the use of antisense technology (Kuipers et al., Plant Mol. Biol. 26 (1994), 1759-1773; Visser et al, Mol. Gen. Genet. 225 (1991), 289-296), RNAi technique (Andersson et al, Plant Cell Rep. 22 (2003), 261-267) or traditional mutational breeding (Muth et al, Plant Biotechnol J. 6 (2008), 576-584) in potato has been described resulting in the synthesis of amylose-free starches and thus to the so-called HighAmyloPectin (HAP) or waxy starches. However, as long as there is a certain level of GBSSI enzymatic activity, maximum amylose levels are yielded (Flipse et al, Theor. Appl. Genet. 92 (1996), 121-127) and hence, the trait "amylose-free starch" is categorized as being recessive. Furthermore, SSIII is known to be mainly responsible for amylopectin synthesis and a length reduction of the outer amylopectin chains via inactivation of the ssIII leads to changes in the viscosity of starch derived from those potato plants in comparison to native starch (EP 0 779 363 A3; Marshall et al, Plant Cell 8 (1996), 1121-1135). Due to its tetraploidy, five allele dosages are possible in cultivated potato plants, i.e. nulliplex to quadruplex. The plant of the present invention has at least one inactive allele of the gbssl gene (H) and one inactive allele of the ssIII gene (P) and at least one functional allele of gbssl and/or ssIII. More specifically, the plant can be simplex (Hl), duplex (H2) or triplex (H3) for the inactive allele of gbssl and simplex (Pl), duplex (P2) or triplex (P3) for the inactive allele of ssIH, or it can be simplex (Hl), duplex (H2) or triplex (H3) for the inactive allele of gbssl and quadruplex (P4) for the inactive allele of ssIH, or simplex (Pl), duplex (P2) or triplex (P3) for the inactive allele of ssIII and quadruplex (H4) for the inactive allele of gbssl, i.e. the potato plants of the present invention can be: H1P1, H2P1, H3P1, H4P1, H1P2, H2P2, H3P2, H4P2, H1P3, H2P3, H3P3, H4P3, H1P4, H2P4, H3P4 for the inactive allele of gbssl and ssIH, respectively. Accordingly, the potato plant of the present invention can be distinguished from wild type potato plants being H0R0, from potato plants being H4P0 which give rise to the above mentioned waxy starches and from potato plants being H4P4 is which all four alleles of gbssl and ssIII are inactivated.

In a preferred embodiment, the potato plant of the present invention is quadruplex (4) for the inactive allele of gbssl (H4) or the inactive allele of ssIII (P4). In a further preferred embodiment, the potato plant of the present invention is quadruplex for the inactive allele of gbssl and simplex, duplex or triplex for the inactive allele of ssIH, i.e. the plant is H4P1, H4P2, H4P3 or the potato plant of the present invention is quadruplex for the inactive allele of ssIII and triplex for the inactive allele of gbssl, i.e. the plant is H3P4.

The inactive allele of ssIII and of gbssl in the potato plant of the present invention can be caused by any mutation leading to inactivation of the ssIII and the gbssl gene, respectively.

In a preferred embodiment, the inactive allele of gbssl in the potato plant of the present invention is caused by one or more mutations in the gbssl DNA sequence set forth under accession number X58453 of the DNA Databank of Japan (DDBJ) Nucleotide Sequence Database. In a further preferred embodiment of the present invention, the guanine (G) at position 1372 and/or the guanine (G) at positon 1407 is substituted with a different nucleic acid. Preferably, the G at position 1372 is substituted with adenine (A) leading to an amino acid substitution of Glycine to Asparagine at positon 100 in the amino acid sequence of GBSSI set forth under accession number Q00775 and/or the G at position 1407 is substituted with adenine (A) leading to miss-splicing of the primary transcript. In particular, the mutation G1372A causes a missense mutation in the highly conserved motif KTGGLG (SEQ ID NO: 7) present in all starch synthases in potato (Nazarian-Firouzabadia & Visser, Biochemistry and Biophysics Reports 10 (2017), 7-16), thereby converting KTGGLG (SEQ ID NO: 7) into KTGGLD (SEQ ID NO: 8) leading to inactivation of the starch synthase. Therefore, a mutation in this motif leading to an inactive allele, i.e. loss-of function is a preferred embodiment for providing inactive alleles of ss genes in accordance with the present invention.

The inactive allele of ssIII in the plant of the present invention is preferably caused by one or more mutations in the ssIII cDNA sequence set forth under accession number X95759 of the DDBJ Nucleotide Sequence Database, i.e. the guanine (G) at position 1849, the cytosine (C) at position 2144, the G at position 1672 and/or the G at position 1897 is substituted with a different nucleic acid. Preferably, the G at position 1849 is substituted with adenine (A) leading to conversion of codon TGG into the stop codon TGA, the C at position 2144 is substituted with thymine (T) leading to conversion of codon CAG into the stop codon TAG, the G at position 1672 is substituted with adenine (A) leading to conversion of codon TGG into the stop codon TGA, and/or the G at position 1897 is substituted with adenine (A) leading to conversion of codon TGG into the stop codon TGA.

In one embodiment, the plant of the present invention is heterozygous for at least two mutations in gbssl and/or ssIH, wherein the two mutations in the ssIII gene are preferably the nucleic acid substitutions G 1849 A and C2144T.

The generation and detection of loss-of function alleles of the GBSS encoding gene using an ethylmethanesulphonate (EMS)-mutagenized dihaploid potato population as the starting material has been described in Muth et al., Plant Biotechnology Journal 6 (2008), 576-584; see also the appended Examples. Whereas N-ethyl-N-nitrosourea (ENU) introduces AT>GC transitions and AT>TA-transversion and N-nitroso-N-methylurea (NMU) introduces GC>AT- transitions and AGC>TA-transversions, EMS solely confers GC> AT -transitions. This constitutes in dicotyledonous plants by far the most prominent base exchanges by natural mutation processes (Ossowski et al. Science 327 (2010), 92-94). Furthermore, Zhang et al. (Plant Physiol. 161 (2012), 20-27) describes methods for the targeted modification of plant genomes using transcription activator- like effector nucleases (TALENs). Voytas, Annual Review of Plant Biology 64 (2013), 327-350 summarizes recent advances in the use of DNA double-strand break (DSB) repair to effect precise alterations of plant genomes allowing not only the possibility of targeted modification in plants, but also that the tools of genome engineering can be routinely deployed to advance both basic and applied plant research.

More recently, the use of rare-cutting endonucleases (e.g., TALE -nucleases) to inactivate at least one (e.g., at least two, at least three, or all four) functional alleles of GBSS to generate potato plants and related products (e.g., seeds and plant parts) that are particularly suitable for providing reduced-amylose starch has been described in international application WO 2015/193858 Al. Of course, in accordance with the present invention materials and methods disclosed in WO 2015/193858 Al may be used to inactivate at least one (e.g., at least two, at least three, or all four) functional alleles of other soluble starch synthase enzymes as well. A detailed method for inactivating one or more alleles of ss genes in tetraploid potato plants in described in WO 2017/192095 and Andersson et al., Plant Cell Rep 36 (2017), 117-128.

Accordingly, in one embodiment, the potato plant of the present invention is generated via means and methods that do not require and therefore do not involve crossing and/or selection.

The present invention also provides a potato plant which gives rise to potato starch which, when in native form extracted from the plant, differs from starch of a corresponding wild type potato plant which is nulliplex for the inactive allele of gbssl and ssIII (H0R0) or from a corresponding potato plant which is quadruplex for the inactive allele of gbssl and nulliplex and/or quadruplex for the inactive allele of ssIII (H4P0, H4P4) or otherwise equivalent lacking GBSSI and/or SSIII activity, preferably wherein the starch is different in terms of amylose content, viscosity, gel transparency (retrogradation) and/or size and shape of starch granules. Furthermore, the present invention provides the starch derived from the potato plants of the present invention.

In particular, starch derived from plants having the "waxy" phenotype, i.e. are quadruplex for the inactive allele of gbssl (H4) and in addition having one, two, or three inactive alleles of ssIH, in particular from plants being H4P1, H4P2, H4P3 and starch derived from plants which are triplex for the inactive allele of gbssl (H3) and having four inactive alleles of ssIII (H3P4) have been compared to starch derived from potato plants which are nulliplex for the inactive allele of gbssl and ssIII (H0R0) and from plants which are quadruplex for the inactive allele of gbssl and nulliplex and/or quadruplex for the inactive allele of ssIII (H4P0, H4P4). The results are shown in Fig. 4.

First of all, the apparent amylose content of the starches obtained from the above described potato plants, called herein for simplification H0R0 starch, H4P0 starch, H4P4 starch, H3P4 starch, H4P1 starch, H4P2 starch and H4P3 starch, etc. has been determined by the method of Hovenkamp-Hermelink (1988) as described in the Examples.

In one embodiment, the potato plants of the present invention which are H4P1, H4P2 and H4P3 give rise to starches having an apparent amylose content which is lower in comparison to the apparent amylose content of starch derived from a H0R0 potato plant and higher in comparison to the apparent amylose content of starch derived from a H4P4 potato plant. Furthermore, the potato plants of the present invention which is H3P4 give rise to starches having an apparent amylose content which higher in comparison to the apparent amylose content of starch derived from a H4P4 and/or a H4P0 potato plant; see Fig. 4A.

In a preferred embodiment, the potato plants of the present invention which are H4P1, H4P2 and H4P3 give rise to starches having an apparent amylose content which is at least twofold decreased and preferably at least threefold to sixfold decreased in comparison to starch derived from a corresponding H0R0 potato plant and which is at least twofold increased in comparison to starch derived from a corresponding H4P4 potato plant. Preferably, the potato plants of the present invention which are H4P1, H4P2 and H4P3 give rise to starches having an apparent amylose content between -0.5% and 2%, in particular in particular between about 1.0% and 1.5% [H4P1], 0% and 1% [H4P2] or -0.5% and 2% [H4P34] in comparison to 11% to 18% of starch derived from a H0R0 potato plant and to -1% to -3% of starch derived from a H4P4 potato plant. Furthermore, the potato plant of the present invention which is H3P4 gives rise to starch having an apparent amylose content which is at least twofold increased and preferably at least threefold to sixfold increased in comparison to starch derived from corresponding H4P4 or H4P0 potato plants. Preferably, the potato plants of the present invention which is H3P4 gives rise to starch having an apparent amylose content between 11% and 16% in comparison to -1% to -3% of starch derived from a H4P4 and to 0% to 3% of starch derived from a H4P0 potato plant. The exact values are listed in Table 1. In this context, an apparent amylose content around 0 % is to be understood that no or nearly no amylose is present in such starches. Accordingly, potato plants which are H4P4, H4P3, H4P2 and H4P1 give rise to starches containing substantially no amylose, whereas H0R0 and H3P4 starches have an apparent amylose content of about 11 to 18 %.

Next to the apparent amylose content, viscosity measurements of the starch gels have been performed and the long term stability of such gels has been analyzed as described in the Examples. In general, gelatinized starch can be used in many applications only for a short time period as viscosity increases quickly upon cooling due to the re-crystallization of amylose molecules. As can be derived from Fig. 4B and C, the potato plant which is H4P0 gives rise to starch which viscosity onset temperature is significantly increased and which peak temperature is decreased in comparison to the native starch derived from the H0R0 potato plant due to the lack of amylose. Similarly, as shown in Example 9, the potato plant which is H4P0 gives rise to starch gels which long term stability is significantly higher than the long term stability of starch gels obtained from native starch derived from the H0R0 plant, i.e. the starch gel derived from a H4P0 potato plant is less viscous after storage at 5°C for three weeks than the starch gel derived from a H0R0 potato plant. The starch gel obtained from H4P0 potato plants is however similar or slightly less stable than starch gel obtained from H4P4 potato plants.

The potato plants of the present invention which are H4P1, H4P2 and H4P3 give rise to starches which have a viscosity onset temperature similar to the starch derived from the H4P0 potato plant and which have a higher viscosity onset temperature in comparison to starch derived from a corresponding H0R0 potato plant. In accordance with this, the peak temperature of the starch derived from the H4P1, H4P2 and H4P3 potato plants of the present invention is similar to the one derived from the H4P0 potato plant and lower in comparison to the peak temperature of starch derived from a corresponding H0R0 potato plant. As shown in Fig. 4G, the potato plants of the present invention which are H4P1, H4P2 and H4P3 give rise to starch gels which have a long term stability similar or slightly higher in comparison to the starch gels derived from the H4P0 potato plant and which have a significantly higher long term stability, i.e. which are more stable in comparison to starch gels derived from a corresponding H0R0 potato plant. In comparison to starch gels derived from a H4P4 potato plant, the potato plants of the present invention which are H4P1, H4P2 and H4P3 give rise to starch gels which are similar stable. As described before, SSIII is responsible for amylopectin synthesis and a length reduction of the outer amylopectin chains via inactivation of the ssIII gene should lead to a reduction in the viscosity onset temperature (EP 0 779 363 A3; Marshall et al., Plant Cell 8 (1996), 1121— 1135). Accordingly, as can be derived from Fig. 4B and C, the potato plant which is H4P4 gives rise to starch showing a reduced viscosity onset temperature in comparison to the starch derived from the H4P1, H4P2 and H4P3 potato plants of the present invention. The potato plant of the present invention which is H3P4 gives rise to starch with a viscosity onset temperature that is even more decreased and with a peak temperature that is increased in comparison to the starch derived from the H4P4 potato plant.

Starch gels derived from a H3P4 potato plant are significantly less stable that starch gels derived from H4P0, H4P1, H4P2, H4P3 and H4P4 potato plants. Surprisingly, starch gels derived from a H3P4 potato plant seem to be in average even less stable than starch gels derived from a H0R0 plant.

In a preferred embodiment, the potato plants of the present invention which are H4P1, H4P2 and H4P3 give rise to starch having a viscosity onset temperature which is in average about 4°C to 5°C higher than the viscosity onset temperature of starch derived from a H0R0 and/or a H4P4 potato plant, preferably wherein the viscosity onset temperature of the H4P1, H4P2 and H4P3 starches is between 64°C and 69°C, in particular between about 66°C and 67°C [H4P1], 64°C and 66°C [H4P2] or 64°C and 69°C [H4P34] in comparison to 60°C to 64°C of starch derived from a H0R0 and a H4P4 potato plant, respectively. The corresponding peak temperature of starch derived from the potato plants of the present invention which are H4P1, H4P2 and H4P3 is in average about 9°C to l l°C lower than the peak temperature of starch derived from a H0R0 potato plant, preferably wherein the peak temperature of the H4P1, H4P2 and H4P3 starches is between 68°C and 73°C in comparison to 74°C to 9l°C of starch derived from a H0R0 potato plant.

Furthermore, the potato plant of the present invention which is H3P4 gives rise to starch with a viscosity onset temperature which in average is 3°C to 4°C lower in comparison to the viscosity onset temperature of starch derived from a H0R0 and a H4P4 potato plant and 7°C to 9°C lower in comparison to the viscosity onset temperature of starch derived from a H4P0 potato plant, preferably wherein the viscosity onset temperature of starches derived of the H3P4 plants of the present invention is between 57°C and 60°C in comparison to 60°C to 64°C of starch derived from a H0R0 and a H4P4 potato plant and to 64°C to 69°C of starch derived from a H4P0 potato plant. The corresponding peak temperature is between 78°C and 80°C. The exact values are listed in Table 3.

Accordingly, based on these results it seems that similar to the gbssl gene, the ssIII gene can be categorized as being recessive since as long as one allele of ssIII is present in the H4 background, the viscosity onset temperature and the peak temperature did not significantly change and only when all four alleles of ssIII are inactive, the viscosity onset temperature significantly decreased due to the lack of amylopectin.

In another preferred embodiment, the potato plants of the present invention which are H4P1, H4P2 and H4P3 each give rise to starch gels which are more stable in comparison to starch gels derived from a H0R0 potato plant, preferably wherein the difference in the storage modulus [AG’] being measured during the shearing of the starch gels, which is calculated via subtracting the storage modulus [Pa] measured directly after cooking of the starch gel from the storage modulus [Pa] measured after storage for three weeks at 5°C, is between about -1.5 Pa and 3 Pa [H4P1, H4P2, H4P3] in comparison to about 35 Pa to 110 Pa as determined for the starch gel derived from a H0R0 plant. Furthermore, the potato plants of the present invention which are H4P1, H4P2 and H4P3 give rise to starch gels which are similar or slightly more stable in comparison to the starch gels derived from a H4P0 potato plant and/or a H4P4 potato plant, preferably wherein the difference in the storage modulus [AG’] being measured during the shearing of the starch gels is between about -1 Pa and 5 Pa for the starch gel derived from a H4P0 potato plant and between about—1.5 Pa and 2 Pa for the starch gel derived from a H4P4 potato plant.

The potato plant of the present invention which is H3P4 gives rise to starch gels which are less stable in comparison to starch gels derived from a H4P0 and/or a H4P4 potato plant, preferably wherein the difference in the storage modulus [AG’] being measured during the shearing of the starch gels, which is calculated via subtracting the storage modulus [Pa] measured directly after cooking of the starch gel from the storage modulus [Pa] measured after storage for three weeks at 5°C, is between about 55 Pa and 165 Pa in comparison to about -1 Pa to 5 Pa as determined for the starch gel derived from a H4P0 potato plant and/or in comparison to -1.5 Pa to 2 Pa as determined for the starch gel derived from a H4P4 potato plant. Surprisingly, starch gels derived from a H3P4 potato plant seems to be in average even less stable than starch gels derived from a H0R0 plant.

Thus, the processability of the starch of the present invention clearly differs from the processability of starch derived from H0R0 and H4P0 potato plants.

Retrogradation of starches is closely related to the formation of inter-chain double helices and occurs over different time scales for the amylose and amylopectin components, amylose retrogradation being more rapid than amylopectin. Thus, HAP-gels lacking amylose are much clearer due to the reduced retrogradation. This has also been shown in the experiments of the present invention for the starch derived from a potato plant which is H4P0 in comparison to starch derived from potato plants having intact gbssl and ssIII alleles, i.e. from plants being H0R0; see Fig. 4D. The clarity of the starch gels has been determined after 14 days as described in the Examples.

Furthermore, it has been observed by Tako et al., Food and Nutrition Sciences 5 (2014), 280- 291, that after storage of about 10 days association will also occur between long outer chains of amylopectin molecules. Hence, a length reduction of the outer amylopectin chains should further enhance the clarity of starch gels. This has been shown as well by the experiments of the present invention. In particular, as depicted in Fig. 4D, potato plants being H4P4 give rise to starches which upon gelatinization produce clearer gels than those derived from a corresponding H4P0 potato plant.

The H3P4 potato plant of the present invention gives rise to starch which gel transparency is lower in comparison to the gel transparency of starch derived from a H4P0 and/or a H4P4 potato plant, preferably wherein the transmission of the gel is between 1% and 2% in comparison to 23% to 42% and 61% to 72% of starch derived from a H4P0 potato plant and a H4P4 potato plant, respectively.

Furthermore, surprisingly, it has been shown that the potato plants of the present invention which are H4P1, H4P2 and H4P3 give rise to starch having a gel transparency which is in average higher in comparison to the gel transparency of starch derived from a H0R0 and a H4P0 potato plant and lower in comparison to the gel transparency of a starch derived from a H4P4 potato plant. In particular, it has been shown that the gel transparency increases with decreasing number of active, i.e. functional ssIII alleles although the results regarding the viscosity of the starches derived from the potato plants of the present invention led to the conclusion that the ssIII gene is recessive.

Thus, the H4P1, H4P2 and H4P3 potato plants of the present invention give rise to starch having a gel transparency which is in average higher in comparison to the gel transparency of starch derived from a H0R0 and a H4P0 potato plant and lower in comparison to the gel transparency of a starch derived from a H4P4 potato plant. In preferred embodiment, the transmission of the gel is between 38% and 47% in case of starch obtained from H4P1 potato plants, 46% and 62% in case of starch obtained from H4P2 potato plants, and 48% and 73% in case of starch obtained from H4P3 potato plants in comparison to 0.5% to 1.5% and 23% to 42% of starch derived from a H0R0 potato plant and a H4P0 potato plant, respectively and to 61% to 72% of starch derived from a H4P4 potato plant. The exact values are listed in Table 4.

Similar effects have been shown when comparing the size and shape of starch granules derived from the plants of the present invention to starch derived from potato plants which are nulliplex for the inactive allele of gbssl and ssIII (H0R0) and from plants which are quadruplex for the inactive allele of gbssl and nulliplex and/or quadruplex for the inactive allele of ssIII (H4P0, H4P4); see Fig. 4E.

In particular, the H3P4 potato plants of the present invention give rise to starch granules having an average relative particle size (d50) which is in average lower in comparison to the relative particle size of starch derived from a H0R0 and a H4P0 potato plant and higher in comparison to the average particle size of a starch derived from a H4P4 potato plant, preferably wherein the particle size is between 30 pm and 39 pm in comparison to 49 pm to 55 pm and 49 pm to 62 pm of starch derived from a H0R0 potato plant and a H4P0 potato plant, respectively and to 25 pm to 37 pm of starch derived from a H4P4 potato plant.

The H4P1, H4P2 and H4P3 potato plants of the present invention give rise to starch granules having an average relative particle size (d50) which is in average lower in comparison to the relative particle size of starch derived from a H0R0 and a H4P0 potato plant and higher in comparison to the average particle size of a starch derived from a H4P4 potato plant. In a preferred embodiment, the potato plants of the present invention give rise to starch granules which particle size is between 43 pm and 49 pm in case of H4P1 and H4P2 potato plants of the present invention and/or between 36 pm and 45 pm in case of H4P3 potato plants of the present invention in comparison to 49 pm to 55 pm and 49 pm to 62 pm of starch derived from a H0R0 potato plant and a H4P0 potato plant, respectively and to 25 pm to 37 pm of starch derived from a H4P4 potato plant. Accordingly, with increasing number of inactive alleles of ssIII in the H4 background of the potato plants of the present invention, the size of the starch granules decreased.

In general, small starch grains are preferably used in food applications since the bigger ones lead to a rough feeling on the tongue during consumption. However, in large scale purification processes, too small starch grains cause difficulties. In particular, it has been shown by the inventors that starch derived from H4P4 potato plants could not be purified as efficiently as for example starch derived from a H4P2 potato plant (Fig. 7), which starch grains are still in average smaller than those from a corresponding potato plant being H0R0; see Fig. 4E. Thus, in one embodiment, the potato plants of the present invention, in particular those being H4P1, H4P2 and H4P3 give rise to starches which can be purified to a higher extend than starch derived from a H4P4 potato plant.

As evidenced by Fig. 5 A to C, not only the size of the starch granules is different in the potato plants of the present invention in comparison to starch derived from potato plants which are nulliplex for the inactive allele of gbssl and ssIII (H0R0) and from plants which are quadruplex for the inactive allele of gbssl and nulliplex and/or quadruplex for the inactive allele of ssIII (H4P0, H4P4), but also the shape of the starch granules changes. In particular, the H0R0 potato plant gives rise to oval starch granules, the H4P1 and H4P2 potato plants of the present invention give rise to starch granules which are already rounder than the ones derived from a corresponding H0R0 potato plant and the starch granules derived from a H4P3 potato plant are rather round than oval. Accordingly, with increasing number of inactive alleles of ssIII in the H4 background of the potato plants of the present invention, the shape of the granules changed from rather oval to round. Thus, an allele dosage effect for ssIII could be shown. Furthermore, the potato plant being H3P4 gives rise to starch granules that have fissures, i.e. cracks which is clearly seen in Fig. 5C. This is of particular interest for some specific applications. Furthermore, the H4P1, H4P2 and H4P3 potato plants of the present invention give rise to starch having a phosphate content which is lower in comparison to starch derived from a H4P4 potato plant and in average higher than of starch derived from a H4P0 potato plant, wherein the phosphate content is between about 850 ppm and 1000 ppm [H4P1], 700 ppm and 1100 ppm [H4P2] or 550 ppm and 1100 ppm [H4P3] in comparison to about 950 ppm to 1350 ppm of starch derived from a H4P4 potato plant and to about 500 ppm to 950 ppm of starch derived from a H4P0 potato plant. The phosphate content of starch derived from a H3P4 potato plant is about between 950 ppm and 1300 ppm and thus higher in comparison to starch derived from a H4P0 and a H0R0 potato plant.

The difference in the phosphate content may have an effect in the processing and/or potential applications of starch obtained from the potato plants of the present invention.

Further changes in H- and P allele dosages and effect on starch characteristics on amylose content and other starch characteristics for potato plants of the present invention with different allele dosages (nulliplex to quadruplex) of inactive gfrv.s7-allclcs (H) and/or ssIII- alleles (P) in addition to those described in detail above, which give rise to embodiments of the present invention are summarized in Example 10 and illustrated Figures 5, 8 and 9 and explained in the legends thereto.

Accordingly, it has been shown that there is indeed an allele dosage effect of the ssIII gene at least in the background of a potato plant having four inactive alleles of gbssl. Thus, the starches derived from the H4P1, H4P2 and H4P3 potato plants of the present invention have novel and surprising properties in that they have a similar apparent amylose content and viscosity than the waxy starches, but having a significantly higher gel transparency and smaller starch grains. The long term stability of starch gels obtained from H4P1, H4P2 and H4P3 potato plants is also similar, but seems to be slightly higher than the long term stability of the waxy starch (H4P0). In comparison, the H4P4 starch has the highest gel transparency, but has a lower viscosity onset temperature and a higher phosphate content than the H4P1, H4P2 and H4P3 starches. In addition, starch obtained from the "double intermediate" genotype H2P2 though carrying the same copy number of functional alleles of gbssl (H) and ssIII (P) genes is substantially different from starch obtained from wild type H0R0 potato plants. Thus, the present invention provides potato plants giving rise to starches with novel and surprising properties that have not been described before and accordingly provides the starches derived from the potato plants of the present invention.

In some embodiments, the plants provided herein can contain further mutations introduced into other Solanum genes. Such mutations can, for example:

provide acrylamide reduction by modifying the expression of genes involved in asparagine synthesis;

prevent black spot bruise by reducing polyphenol oxidase-5 expression;

prevent Potato Virus Y by reducing elF4E gene expression;

prevent late blight; and/or

improve nematode, herbicide, or insect resistance.

Thus, the methods provided herein can be used to obtain gene stacking in a Solanum trait.

The present invention also encompasses methods for producing starch products using the starch obtained from the Solanum plants, plant parts and plant cells of the present invention, as well as industrial starch products made by such methods. These products include, without limitation, starches useful in the paper, textile, adhesive, and packing industries. Such starch products can be produced using various procedures and types of equipment, although all follow a similar process. For example, potatoes can be dropped into water flumes that clean the potatoes of stones and dirt. After further cleaning in a washer, the potatoes can be moved to a grinder or crusher to liberate the starch from the potato cells. The resulting slurry can be passed through a screen or rotary sieve to separate the fiber and potato skins, and the starch solution can then be further purified to remove soluble and insoluble impurities by alternate cycles of filtration and re-dispersion in water. The purified starch then can be dewatered, dried, and collected; see, for example, Robson, "U.S. Environmental Protection Agency. Starch Manufacturing: A Profile," North Carolina: Center for Economics Research, March 1994 (RTI Project Number: 25 35U-5681-71 DR).

Accordingly, the present invention also relates to methods of making starch or a derivative thereof, wherein the methods comprise the step of extracting the starch content from the potato plant or the tuber of the present invention. Experimental details regarding the extraction of starch from potato tubers are given in the Examples. The method of the present invention may further comprise the step of modifying the extracted starch by physical, enzymatic and/or chemical processing in vitro. Methods and processes for in vitro modification of starch are well known and include those, for example, disclosed in European patent application EP 0 796 868 A2 and international application WO 2017/192095. The most common modification methods are cross-linking, phosphorylation, acetylation, hydroxylpropylation, 2-octenylsuccinylation with both the sodium and the aluminum salt forms, succinylation, cationization, oxidation, enzymatic modification, acid treatment of starch, pyro-dextrinization and alkaline roasting of starches as well as combinations thereof The present invention is not limited to the modification methods disclosed, as chemical or non-chemical modifications are considered to be known by a person skilled in the art. Thus, all kinds of modifications described in literature and publications can be applied on the starch products of the present invention.

The present invention also encompasses the starch derived from the potato plants and the potato tubers of the present invention and/or the starch extracted by the method of the present invention as well as starch based or starch containing products comprising the starch of the present invention. In particular, the starch of the present invention has all the characteristics as described above in context with the potato plant of the present invention. In this context, the present invention also relates to a method of producing a starch based or starch containing product.

In another aspect of the present invention, the starch or the starch based or starch containing products can be used in several different applications. Thus, in one embodiment, the purified starch may be used in its native state or the starch may alternatively be used in a modified stage, wherein the starch has been modified by anyone of the modification methods known by a person skilled in the art as described above. The purified modified or unmodified starch can be used for example in the food, feed, paper, textiles and adhesives industries, for bioenergy production, and as additives for pharmaceutical and personal care products.

The above disclosure generally describes the present invention. Unless otherwise stated, a term as used herein is given the definition as provided in the Oxford Dictionary of Biochemistry and Molecular Biology, Oxford University Press, 1997, revised 2000 and reprinted 2003, ISBN 0 19 850673 2. Several documents are cited throughout the text of this specification. The contents of all cited references (including literature references, issued patents, published patent applications as cited throughout this application including the background section and manufacturer's specifications, instructions, etc.) are hereby expressly incorporated by reference; however, there is no admission that any document cited is indeed prior art as to the present invention. A more complete understanding can be obtained by reference to the following specific examples which are provided herein for purposes of illustration only and are not intended to limit the scope of the invention.

EXAMPLES

In the following, specific materials and methods used in context with the present invention are listed. The examples which follow further illustrate the invention, but should not be construed to limit the scope of the invention in any way.

The generation of potato plants having inactive gbssl alleles, in particular clones having a mutation in the gbssl sequence (accession number X58453), wherein the G at positon 1372 and/or the G at position 1407 is substituted with A leading to an amino acid substitution of Glycine to Asparagine at positon 100 in the amino acid sequence of GBSSI set forth under accession number Q00775 (E433) and the G at position 1407 is substituted with adenine (A) leading to miss-splicing of the primary transcript (El 100) including the identification of the exon/intron structure of the gbssl gene and of the region most suitable for screening for new alleles; seed production of diploid potatoes expressing a gametophytic self-incompatibility system; inactivation of gbssl alleles via ethylmethanesulphonate (EMS) treatment and selection for missense and splice site mutations; propagation of the EMS population and genotypic analysis; culturing of clones carrying the desired mutation(s); and duplication of the chromosome set by doubling of diploid clones carrying the mutated allele(s) in single copy, leading to tetraploid clones possessing the inactive ss allele(s) each in duplex is described in detail in " BIOPLANT et al., "Neue Wege zur Erstellung und Nutzung von Spezialstarken" DOI: l0.23l4/GBV:5l366385l (available from the University of Hannover : Techn. Informationsbibl. und Univ.-Bibl.) and Muth et al., Plant Biotechnology Journal 6 (2008), 576-584.

The generation of potato plants having inactive ssll and ssIII alleles, respectively, including ssIII clone R148 having a G at position 1849 (accession number X95759) substituted with A leading to conversion of codon TGG into the stop codon TGA and ssIII clone B309 having a C at position 2144 (accession number X95759) substituted with T leading to conversion of codon CAG into the stop codon TAG as well as the identification of the exon/intron structure of the ssll and ssIII gene and of the regions, most suitable for screening for new alleles; seed production of diploid potatoes expressing a gametophytic self-incompatibility system; inactivation of ssll and ssIII alleles, respectively, via EMS treatment and selection for missense and splice site mutants; propagation of the EMS population and genotypic analysis; culturing of clones carrying the desired mutation(s); and duplication of the chromosome set by doubling of diploid clones carrying the mutated allele(s) in single copy, leading to tetraploid clones possessing the inactive ss allele(s) each in duplex is described in detail in BIOPLANT et al, "Verbundvorhaben: Zuchterische Optimierung von Spezialstarken, Teilvorhaben 1 : Zuchtung; Teilvorhaben 2: Erbgut-Analytik; Teilvorhaben 3: Starkeanalytik (2013); DOI: l0.23l4/GBV:832680079 (available from the University of Hannover : Techn. Informationsbibl. und Univ.-BibL); see, e.g., Figure 9 and Table 3 for the ssIII gene and Figure 10 and Table 4 for the ssll gene.

In accordance with the present invention to generate Solanum species, i.e. potato plants having one or more inactive alleles of at least two of the ss genes gbssl, ssJ ssll and ssIII the mentioned disclosures can be combined either alone or in combination with other techniques known in the art and referred to above, for example TALENs as described in international application WO 2015/193858 and/or the CRISPR/Cas based approach as described in international application WO 2017/192095 and Andersson et al., Plant Cell Rep. 36 (2017), 117-128; see also supra. For example, WO 2017/192095 describes that mutations can be introduced into several alleles of one or several genes in one application of the CRISPR/Cas9 complex, which has been illustrated for GBSSI; GBSSI + SSIII; GBSSI + SSII, and GBSSI +SSII + SSIII. To that end, to gain a complete disruption of enzyme activities, all 4 alleles of the used tetraploid potato genotype were targeted for each gene; see Example 6 of WO 2017/192095.

Nevertheless, in the appended Examples with reference to the drawings one further non limiting and preferred way of carrying out the invention claimed is provided. Material and methods

Determination of the amylose content in starch

Determination of the amylose content in starch was performed according to a method described in Hovenkamp-Hermelink et al, Potato Research 31 (1988), 241-246. For starch extraction from tubers, 80 mg (+/- 10 mg) material were extracted from the pulp of a potato tuber by using a cork borer, were transferred into a test tube and immersed in 0.5 ml 40 % perchloric acid (5.7 ml 70 % perchloric acid solution + 4.3 ml H₂0) under gentle squeezing with a glass rod at room temperature. After 5 min, the suspension was diluted with 8 ml of H₂0. Afterwards, the tuber debris was allowed to settle to the bottom of the test tube for 15 min. I₂-K₂ staining was achieved by mixing 200 mΐ of the suspension with 1.25 ml diluted Lugol's solution (1 part Lugol's iodine, 4 parts H₂0). The mixture was vortexed thoroughly. Absorbencies were measured immediately after mixing in a UV-spectrophotometer model UV-1601 (Shimadzu Corporation) equipped with a program for measuring at two wavelength and recording the ratio of the absorbencies after correcting for the blanks which consisted of a mixture of 1.25 ml diluted Lugol's solution and 200 mΐ H₂0.

Large-scale isolation of starch

First of all, the harvested potatoes are washed with water and impurities like stones were sorted out. The washed potatoes were minced with a grater and the grated potatoes were collected in two 20 1 buckets. Afterwards, the preservative sodium bisulphite was added. A sample from the grated potatoes was taken and dried at 45°C in an oven with recirculating air. By using a pump, the grated potatoes were transferred into a jet extractor, in which the water contained in the fruit and the pulp were separated from the starch. This jet extractor comprises a rotating fine sieve, that allows the starch grains to pass through but not the pulp. The starch suspension was collected and transferred into a big ton via using a pump. After settlement of the starch, the supernatant was discarded, the starch suspended and transferred to a 20 1 bucket. Again the starch settled down and the supernatant was discarded. The upper layer was rinsed with water and again the starch was suspended. This procedure was repeated until a clean white starch had been obtained. The washed starch suspension was centrifuged, the supernatant discarded and the starch was dried over night at 45°C to a moisture content of 17- 20 % in an oven with recirculating air. In the last step, the starch was milled. Determination of viscosity

The viscosity of starch was measured using a Viscograph-E of Brabender GmbH & Co. KG. For calculating the weight of the sample to be analyzed, the moisture content of the starch was determined using a Halogen Moisture Analyzer HR 73 of Mettler Toledo. For this analysis, 2.5 g starch were dried at l30°C until constant mass was reached. For measurement of the viscosity, 18 g bone dry (atro) were weighted and filled up with distilled water until 450 g were reached. The measurement was performed with 350 cmg and an initial temperature of 25°C. The temperature was raised with l.5°C/min until 95°C were reached, was kept for 30 min and subsequently decreased to 25°C. The starch solution prepared for measurement of the viscosity was also used for assessment of the clarity and texture of the gels.

Determination of the long term stability of starch gels

The difference in the storage modulus [AG’] being measured during the shearing of starch gels, which was calculated via subtracting the storage modulus measured directly after cooking of the starch gels from the storage modulus measured after storage of the starch gels for three weeks at 5°C served as measure for the long term stability of the starch. For determination of the storage modulus, the starch solution (4 %) prepared for the viscosity measurements as described above was used applying the rheometer MCR 301 of Anton Paar GmbH, Graz, Austria. The storage modulus was measured directly after cooking and after three weeks by a frequency sweep. G’ was noted at 1.007 Hz. The solution has been stored at 5°C. The storage modulus G' [Pa] describes the elastic properties of the starch solution/starch (Mezger, The Rheology Handbook, 3rd revised edition Hanover: Vincentz Network (2011)). Thus, storage modulus G' (G prime, in Pa) represents the elastic portion of the viscoelastic behavior, which quasi describes the solid-state behavior of the starch gel. Accordingly, the lower the difference in the storage modulus [AG’] of the starch gel directly after cooking of the starch gel and after storage, the higher the stability of the starch gel because of the higher degree of keeping the elastic properties of the initial starch gel.

Determination of the clarity of the gels

The clarity of the starch solution (4 %) prepared for the viscosity measurements as described above was determined using the photometer DR 6000 of Hach Fange GmbH, Dusseldorf, Germany. The transmission of the solution was measured at 655 nm directly after cooking and during the following 14 days. The solution has been stored at 5°C. Size distribution of starch grains

The size distribution of starch grains was analyzed by using the Laser Diffraction Particle Size Analyzer LS 13 320 of Beckman Coulter GmbH, Krefeld, Germany. Thereby, the wet module was applied. With small sample quantities, an optimal concentration for measurement was set to 8 - 12%. The device automatically calculated average values from a measuring period of 1 min.

Determination of phosphate content

The phosphate content was determined using the ICPE 9000 of Shimadzu. First of all, 0.5 g starch, 6.0 ml distilled water and 3.0 ml 65% nitric acid were mixed and the sample was digested using the Multiwave Go of Anton Paar GmbH, Graz, Austria. Afterwards, the digested sample was transferred to a 25 ml volumetric flask and was filled up to 25 ml with distilled water. The solution was transferred into a test tube which was subjected to measurement using the ICPE 9000 of Shimadzu. The phosphate content was determined based on a calibration curve.

Plant material

Potato tubers ( Solanum tuberosum L.) were either grown in pots of soil based compost (25cm diameter) in a greenhouse with minimum temperature of l2°C or in the field (loamy soil, about 28 soil points) at the Baltic Sea (Mecklenburg Pre-Pomerania). Good agricultural practice was applied. Vegetation time was from April to September. Then upper parts of the plants were destroyed and tubers were harvested after skin hardening.

Example 1: Identification of the exon/intron structure of ssIII and of the region most suitable for screening for new alleles

The screening for new alleles in heterozygous autotetraploid potato plants by classical approaches (Cell-nuclease) was not possible due to high SNP-densities. Instead, Sanger sequencing had to be used. To reduce the complexity for finding crossing partners being compatible for this analysis, diploid potatoes (2 alleles per crossing partner, 4 alleles in total) were employed which must not have any InDel-polymorphisms in the analysed region which would corroborate the sequence analysis. At the beginning, only the cDNA sequence (accession number: X95759) of the ssIII gene of Solanum tuberosum was known but no corresponding genomic sequence was available. Since the sequencing of the genome of the closely related tomato Solanum lycopersicon was already in an advanced state, the corresponding databases were screened (http://solgcnomics.nct/gcnomcs/So/i/m/m_ lycopersicum/geno me_data.pl). A sequence was found (accession number: AC215407), being positioned at chromosome 2 analogous to the ssIII gene of Solanum tuberosum. Furthermore, a first sequence draft was available for the wild species Solanum phureja DM (http://potatogenomics.plantbiology.msu.edu/), but no scaffold could be identified being coupled to chromosome 2 and containing the ssIII gene (St.AC.00l.Scaffold000l48).

Further homologous cDNA sequences have been found via BLAST search using the primary databases of the "RZPD Deutsches Ressourcenzentrum fur Genomforschung GmbH" (http://gabi.rzpd.de/database/cgi-bin/Blast.pl.cgi). The homologous parts of these sequences have been detected by means of the program clustalW (http://www.ebi.ac.uk/Tools/msa/ clustalw2/). Afterwards, based on the consensus sequence, an exon/intron structure could be determined with help of the program Spidey (http://www.ncbi.nlm.nih.gov/spidey/).

Based on the results of the above described approaches, the ssIII gene was determined to consist of 14 exons and 13 introns. The size of the exons is between 60 bp and 1540 bp and the size of the introns between 941 bp and 1100 bp. The structure of the analyzed region is schematically visualized in Fig. 1.

Inactivation of ssIII alleles has been performed via EMS treatment; see below. For the screening of EMS populations for inactive ssIII alleles, such gene regions are of particular interest, in which the probability is high that EMS mutagenesis (transition of G to A and of C to T, respectively) leads to stop codons. The nucleotides encoding for tryptophan (TGG), glutamine (CAG and CAA) as well as for arginine (CGA) can be converted into the corresponding stop codons TAG, TGA and TAA.

A further criterion for the selection of a suitable gene region is the amount and size of the introns. In this context, a small number of small introns is preferred. Based on these criterions, an about 1.8 kbp region of the ssIII gene spanning exons 3 to 5 has been selected for high-throughput screening; see also BIOPLANT et al., (2013), supra. Example 2: Generation of potato plants having inactive ssIII alleles

Seed production and EMS treatment

For seed production there are further criterions besides matching alleles of the target gene. Diploid potatoes express a gametophytic self-incompatibility system. By these criteria the diploid breeding lines B-56 (H16) and H01/308/8 (H95) and H96/634/38 (H69) were chosen and crossed for seed production. For each crossing, 40 pollen receivers and 16 pollen donors were grown. In order to efficiently produce seed and berries, the generation of tubers had to be suppressed. Otherwise, the potato plant would stop reproducing sexually and accordingly, no seeds would be produced. There are two techniques available to suppress the generation of tubers. Either the main tuber can be planted onto a stone, in order to recognize the generation of progeny tubers and to remove them directly or in vitro plants which have been selected as crossing partners can be propagated in vitro and subsequently grafted onto tomato in order to harvest the generated tubers leading to a continuous growth and flower formation, wherein the latter alternative has been successfully employed for the generation of seeds of the present invention. Subsequently, 4,000 seeds per crossing combination have been treated with 1.6% Ethyl methanesulfonate (EMS) for 16 h and with the following modifications a) to c). a) N₇-alkylguanine: no biological effect, same effect than guanine

b) N3-alkylguanine: toxic effect since it is not recognized by the enzymes and thus, leads to suppression of transcription and replication. However, in plants it may lead to sequence modifications via the mechanisms of error-prone DNA repair.

c) Oe- alkylguanine: results in G/C- to A/T- transitions.

The seeds have been additionally treated with gibberellic acid (GA3) in order to stop the seed dormancy and have been planted afterwards. The first population after mutagenesis (M) has been harvested and the tuber dormancy stopped via treatment with GA3, in order to grow the next, vegetative generation (vlM). Since the plants grow from a limited meristematic area ("eye") it is assumed that the plants are substantially homogenous.

Propagation of the EMS population and genotypic analysis

As the plant embryo in the seed is already a multicellular organism, not all cells are mutated and the mutated cells may carry different mutations. Plants of this M-Generation which grow out of the mutated seed are genetic chimaeras. When tubers were harvested, tuber dormancy was broken by GA3-treatment. The resulting plants represented the first vegetatively grown generation after the mutagenesis and should represent a genetically homogenous plant. The region of the ssIII gene (exons 3 to 5) identified as described in Example 1 has been analysed via HTS analytics regarding EMS induced mutations. The 1.8 kbp region of the ssIII gene has been amplified via PCR, the PCR-products have been purified and sequenced. A consensus sequence of the 1.8 kbp region of the ssIII gene of analysed parental clones H16 and H69 (without mutations) is set forth in SEQ ID NO: 1. The generated trace files have been analysed regarding new EMS generated SNPs using the program CLC Main Workbench 6" (CLCbio.com). Meanwhile, the genomic sequence of the ssIII gene of Solanum tuberosum has been made publicly available (scaffold00099, JH137887). In addition, Fig. 2 shows an alignment of SEQ ID NO: 1 with the corresponding 1.8 kbp fragment of the cDNA sequence set forth under accession number X95759 of the DDBJ Nucleotide Sequence Database.

The following PCR program and primers have been used for the EMS screening:

Primer pair: SSIIIfw5 : 5’-gag gtc ttt cca ctt tga aga atg-3’ (SEQ ID NO: 2)

SSIIIrevl7: 5’-cag ttg etc tga cat ggg tgc-3’ (SEQ ID NO: 3)

PCR program: 80°C 1 min

94°C 2 min

94°C 30 sec

60°C 30 sec

72°C 2 min

72°C 5 min

20°C hold

PCR set up: 12.5m1 GoTaq G2 Hot Start Colorless Master Mix (2x, Promega GmbH, order number: M7433)

Imΐ genomic DNA (isolated via Wizard Magnetic 96 Plant System, custom configuration, Promega GmbH, order number: FF3761X)

1 mΐ per primer (10mM)

1.5m1 MgCl2 (25mM)

Sequencing: SSIIIrevl7seq: 5’-tgt-cgc-ctg-ctg-aaa-atg-3’ (SEQ ID NO: 4)

SSIIIfwl8: 5’-get tgc atg age ttc cac aat tat ac-3’ (SEQ ID NO: 5) SSIIIrevl8: 5’-gta taa ttg tgg aag etc atg caa gc-3’ (SEQ ID NO: 6)

The following null alleles have been identified, which exact positions are depicted in the alignment of Fig. 2. ssIII B309: C at position 2144 (accession number X95759) is substituted with T leading to conversion of codon CAG into the stop codon TAG (formerly named A 309) ssIII R148: G at position 1849 (accession number X95759) is substituted with A leading to conversion of codon TGG into the stop codon TGA (formerly named P 148)) ssIII GR457: G at position 1672 (accession number X95759) is substituted with A leading to conversion of codon TGG into the stop codon TGA

ssIII R721 : G at position 1897 (accession number X95759) is substituted with A leading to conversion of codon TGG into the stop codon TGA (formerly named P 721)

Culturing of clones carrying mutations

Preferentially, clones having new stop codons have been transferred to tissue culture. Accordingly, several lateral meristems have been isolated and the resulting propagation material was obtained in form of separate sub clones. After surface sterilization, they were transferred to tissue culture. Since it cannot be excluded that those plants are genetic chimaeras, it has to be shown that the mutations were still present in the established tissue cultures. In addition, sensitive media have been used to test for the absence of microorganisms. Several plants per sub clone have been transferred to the green house and tested for the absence of microorganisms via ELISA. Accordingly, only healthy sub clones have been maintained in the tissue culture.

Duplication of the chromosome set

The set of chromosomes of the diploid clones has been doubled resulting in tetraploid clones. Intemodes have been subjected to a short callus phase via appropriate concentration and ratios of phytohormones. In this phase, they tend to duplication of the chromosome set without using agents like colchicine and oryzalin. Four clones comprising a stop codon in the ssIII gene (B309, R148, GR457 and R721) have been transferred into tissue culture. Induction of the short callus phase led to doubling of the chromosome set of the diploid EMS clones; see BIOPLANT et al. (2013), supra The obtained clones were tested with regard to successful genome doubling and presence of the mutation.

When using the original EMS mutagenesis method in seed of diploid potato plants, the mutations occurred in the embryo being already multicellular. Accordingly, the obtained plants were genetic chimaeras containing mutated and non-mutated tissue. Although several "purification steps" had been performed, i.e. growth of the respective next vegetative generation from a limited meristematic area of the "eye" of the tuber, genetically homogenous plants will be obtained only after the first crossing comprising the presence of a single cell state (oocyte, spermatocyte). Clones B309, R148, GR457 and R721 having stop codons in the gene of interest, i.e. the ssIII gene have been generated in which the chromosome doubling and verification of mutations have been successfully performed. Since these clones are derived from the chromosome doubling of diploid clones carrying the mutated alleles in single copy, the tetraploid clones possess the inactive ssIII alleles each in duplex.

Example 3: Generation of clones having inactive ssIII and gbssl alleles

The generated clones B309 and R148 possessing the inactive ssIII alleles each in duplex have been used as pollen receiver in subsequent crossings with clones being homozygous (quadruplex) for inactive gbssl alleles. In particular, clones having a mutation in the gbssl sequence (accession number X58453), wherein the G at positon 1372 and/or the G at position 1407 is substituted with A leading to an amino acid substitution of Glycine to Asparagine at position 100 in the amino acid sequence of GBSSI set forth under accession number Q00775 (E433) and/or the G at position 1407 is substituted with adenine (A) leading to miss-splicing of the primary transcript (El 100). In particular, choice of breeding clones aimed at employing both inactive gbssl alleles El 100 and E433 in order not introduce inbreeding effects when breeding for the recessive trait "free of amylose" and/or for "reduced/ free of long side chains of amylopectin". A simplified crossing scheme is depicted in Fig. 3. Since a person skilled in the art is able to perform appropriate crossings in order to receive clones having different allele dosages of the inactivated ssIII and gbssl alleles, an elaborated crossing scheme in not necessary and not shown here.

Example 4: Starch composition

The apparent amylose content of starches derived from H3P4, H4P4, H4P3, H4P2, H4P1, H4P0 and H0R0 potato plants has been determined colorimetrically by iodine staining as described in "Material and methods". The results are shown Fig. 4A and the exact values are listed in Table 1. In addition, the presence or absence of amylose in starch derived from the respective potato plants was confirmed by microscopic examination of iodine stained granules which is exemplarily shown in Fig. 6, where granules of starch derived from a H4P2 potato plant were compared to starch granules derived from a H0R0 potato plant. It was shown that starch granules of the H0R0 potato plant were stained uniformly blue indicating the presence of amylose in comparison to the starch granules of the H4P2 potato plant which were stained slightly red.

Table 1: Apparent amylose content of starches derived from H3P4, H4P4, H4P3, H4P2,

H4P1, H4P0 and H0R0 potato plants. For determination of the apparent amylose content, different clones of the respective genotypes have been used. Example 5: Starch morphology, size of the starch granules and purity of the starch

The size and shape of starch granules derived from H3P4, H4P4, H4P3, H4P2, H4P1, H4P0 and H0R0 potato plants has been determined. In particular, the size and shape of starch granules derived from H3P4, H4P3, H4P2 and H4P1 have been compared to the ones derived from H4P4, H4P0 and H0R0 potato plants. The results of the size determination are shown in Fig. 4E and the shape (oval to round) is visualized in the diagram of Fig. 5 A. The exact values of the size determination are listed in Table 2.

Furthermore, microscopic analysis has been performed. The results are depicted in Fig. 5B and 5C. In particular, starch granules derived from H4P0, H4P1, H4P2, H4P3, H4P4 and H3P4 potato plants are shown and it can be seen that the size decreased and the starch granules turned rounder with increasing number of inactivated ssIII alleles (P). The starch grains derived from a H0R0 potato plant are not shown. Furthermore, Fig. 5C shows that starch granules derived from a H3P4 potato plant have deep cracks or fissures.

During large scale purification of starch derived from the potato plants being H3P4, H4P4, H4P3, H4P2, H4P1, H4P0 and H0R0 as described in "Material and methods", it was shown that too small starch grains caused difficulties. In particular, it has been shown that starch derived from H4P4 potato plants could not be purified as efficiently as starch derived from a H4P2 potato plant which starch grains are still in average smaller than those from a corresponding potato plant being H0R0; see Fig.7.

Table 2: Size of starch granules derived from H3P4, H4P4, H4P3, H4P2, H4P1, H4P0 and

H0R0 potato plants. For determination of the size of the starch granules, different clones of the respective genotypes have been used.

Example 6: Effects on gelatinization behavior of starch

The physical properties of starch granules derived from H3P4, H4P4, H4P3, H4P2, H4P1, H4P0 and H0R0 potato plants have been determined by viscometric analysis using the Viscograph-E of Brabender as described in "Material and methods". In particular, the viscosity onset temperature and the peak temperature have been determined. The results are depicted in Fig 4B and C and the corresponding values are listed in Table 3.

Table 3: Viscosity onset and peak temperature of starch suspensions made from starches derived from H3P4, H4P4, H4P3, H4P2, H4P1, H4P0 and H0R0 potato plants. Different clones of the respective genotypes have been used for the measurements.

Fig. 8 is a viscogram showing the viscosity of starch suspensions during the course of the temperature program. The measurement was performed with 350 cmg and an initial temperature of 25°C. The temperature was raised with l.5°C/min until 95°C were reached, was kept for 30 min and subsequently decreased to 25°C. In particular, the data of starch derived from H3P4, H4P4, H4P2, H4P0 and H0R0 potato plants (A) and H3P4, H4P4, H1P4, H2P4, H2P2 and H0P4 potato plants (B), see Table 8, infra, are plotted visualizing the different viscosity behavior dependent on the amount of inactive gbssl and ssIII alleles.

Example 7: Clarity of the starch gels

The clarity of starch gels derived from H3P4, H4P4, H4P3, H4P2, H4P1, H4P0 and H0R0 potato plants has been determined via measuring the transmission at 655 nm directly after cooking and during the following 14 days as described in "Material and methods". The results are depicted in Fig. 4D and the exact values are listed in Table 4.

Table 4: Clarity of starch gels made from starches derived from H3P4, H4P4, H4P3, H4P2,

H4P1, H4P0 and H0R0 potato plants. The clarity of the gels has been determined via measuring the transmission at 655 nm. Different clones of the respective genotypes have been used for the measurements. Example 8: Phosphate content of starch

The phosphate content of starch derived from H3P4, H4P4, H4P3, H4P2, H4P1, H4P0 and H0R0 potato plants has been determined using the ICPE 9000 of Shimadzu as described in "Material and methods". The relative phosphate contents are depicted in Fig. 4F, wherein the mean value of the phosphate content of starch derived from a H0R0 potato plant was set to 100%. The exact values are listed in Table 5.

Table 5: Phosphate content of starch derived from H3P4, H4P4, H4P3, H4P2, H4P1, H4P0 and H0R0 potato plants. Different clones of the respective genotypes have been used for the measurements. Example 9: Long term stability of starch

The long term stability of starch gels derived from H3P4, H4P4, H4P3, H4P2, H4P1, H4P0 and H0R0 potato plants has been determined as described in "Material and methods". In particular, the difference in the storage modulus [AG’] being measured during the shearing of starch gels, which was calculated via subtracting the storage modulus [Pa] measured directly after cooking of the starch gels from the storage modulus [Pa] measured after storage of the starch gels for three weeks at 5°C, has been determined. The results are depicted in Fig. 4G and the exact values are listed in Table 6.

Table 6: Long term stability of starch gels made from starches derived from H3P4, H4P4, H4P3, H4P2, H4P1, H4P0 and H0R0 potato plants. The long term stability of the gels has been determined via measuring the difference in the storage modulus being measured during the shearing of starch gels using a rheometer. Different clones of the respective genotypes have been used for the measurements.

In summary, it has been shown that the starches obtained from H4P1, H4P2 and H4P3 potato plants have novel and surprising properties in that they have a similar apparent amylose content, viscosity and phosphate content than the waxy starches (H4P0), but a significantly higher gel transparency and smaller starch grains. The long term stability of starch gels obtained from H4P1, H4P2 and H4P3 potato plants is also similar, but seems to be slightly higher than the long term stability of starch gels obtained from the waxy starch (H4P0). In comparison, the H4P4 starch has the highest gel transparency, but has a lower viscosity onset temperature and a higher phosphate content than the H4P1, H4P2 and H4P3 starches. In addition, the H4P4 starch consists of the smallest starch granules which causes difficulties in the purification process. Accordingly, the starches obtained from H4P1, H4P2 and H4P3 potato plants can be used in various applications, for example in the food industry, where pure starches are required and small grains are preferred due to the rough feeling on the tongue during consumption caused by big starch granules. Furthermore, various applications can make use of the different grades of gel transparency and viscosity of the starch solutions that could not be obtained with the H4P0 or H4P4 starches.

Regarding most of the analyzed properties, the starch obtained from H3P4 potato plants behaves similar to starch derived from unmodified potato plants (H0R0) but the viscosity onset temperature is significantly lower. Furthermore, the long term stability of starch gels derived from H3P4 potato plants seems to be lower than of starch derived from H0R0 plants. In addition, the starch granules of H3P4 starch have deep cracks and fissures which is of particular interest for industrial applications since this might change for example the swelling behavior.

Example 10: Changes in H- and P allele dosages and effect on starch characteristics

In the following Tables 7 to 12, illustrated by Figures 5, 8 and 9 changes in H- and P allele dosages and effect on amylose content and other starch characteristics are illustrated for potato plants of the present invention with different allele dosages (nulliplex to quadruplex) of inactive gfiv.s7-allclcs (H) and/or s.s///-al lclcs (P), i.e., potato plants which are quadruplex (4) for the inactive allele of gbssl (H4) and simplex (1), duplex (2) or triplex (3) for the inactive allele of ssIII (Pl, P2, P3) and plants which are quadruplex (4) for the inactive allele of ssIII (P4) and simplex (1), duplex (2) or triplex (3) for the inactive allele of gbssl (Hl, H2, H3); or duplex (2) for the inactive allele of gbssl (H2) and duplex (2) for the inactive allele of ssIII (P2) vis-d-vis wild type plants and plants which are quadruplex for inactive gfrv.s7-al lclcs (H4) and/or s.s///-al lclcs (P4).

In this context, it is well known in the literature that a plant produced product may vary due to geno- and phenotype. Variations due to the genotype are depicted here. Phenotypic variations in starch applications due to harvesting date, tuber size and environmental influences due to year-to-year weather derived effects are described (Svegmark et al., Carbohydrate Polymers 47 (2002), 331-340). Thus not only mean values but also min/max-borders are given due to variations in the genotype (besides inactive gbssl- and s.s///-al lclcs) and also variations due to culture conditions (field versus greenhouse, GH). Thus in the "overlap"-region H4P4 and H3P4 where analyses for starches from both cultivation systems are given this is obvious. Hence for the important characteristic long term stability values are given for the maximal difference and the minimal difference between clones belonging to the H4P4 and H3P4 genotype. This is done separately for each production system (field, greenhouse). Instead value is given in that the maximal/minimal distance between the values.

Thus, the distance for long term stability between H4P4 and H3P4 clones may vary between 116 Pa and 62 Pa (field grown tubers) and 251 Pa and 90 Pa (greenhouse grown tubers). In the step from H4P4 to H3P4 changes in long term stability may change due to growth conditions and/or size of tubers. These changes were at maximum 251 Pa and at minimum 62.4 Pa.

Table 7: Apparent amylose content.

Table 8: Viscosity onset temperature.

Table 9: Gel transparency day 14, %.

Table 10: Particle size (d50)

Table 11: Phosphate content (ppm).

Table 12: Long term stability. As can be inferred from Table 7 and 11 and shown in Figures 9A and 9C the values for phosphate content drop from H4P4 to H2P4. At H1P4 amylose is formed again. However, only the amylopectin is phosphorylated. If the degree of phosphorylation of the amylopectin is the same, it decreases if the reference point is the total strength. Indeed, a so-called "P4 effect" may be noted in that all "P4" starches which do not have ssIII activity and therefore also long side chains, have higher phosphate values. Once ssIII activation occurs ("P2" starches) and the long side chains are formed, the phosphate content decreases. Without intending to be bound by theory one possible interpretation is that the branches of amylopectin (formed by starch-branching enzyme (SBE) sbel/sbell) insert branches carrying phosphate groups as an energy source for the subsequent chain synthesis; see, e.g., Rydberg et al., Eur J. Biochem. 268 (2001), 6140-6145; Brummell et al., BMC Biotechnol. 15 (2015), 15:28; and Li and Gilbert, Planta 243 (2016), 13-22. These phosphate groups are used by the ssIII enzymes, so that only in P4 plants (no ssIII enzymes) the phosphate groups are retained. P4 starches are therefore more phosphorylated than other starches.

Likewise, and again without intending to be bound by theory a corresponding "H4 effect" may be observed for which the phosphate content is calculated with reference to the total strength. Now, only the amylopectin is posphorylated. The amylose content hardly decreases from HO to H3, but then in a big step from H3 to H4. Then there is no gbssl enzyme and therefore no more amylose present. For all "Pn" strengths, the phosphate content should be similar for each "Pn level" from HO to H3. In H4 plants/starch, however, amylose is missing, which accounts for approx. 20% of the total starch. This increases the phosphate content/total starch purely mathematically, while the phosphate content/amylopectin should remain approximately the same.

As shown in Figure 5, fissures occur as soon as amylose, i.e. from H3P4 to H0P4 is stored again in the starch grains, which lack the long side chains.

As can be inferred from Table 8, 9 and 12 and illustrated in Figures 9B, 9D and 9F regarding gelatinization and peak temperature, the highest degree of crystallinity and stability is probably found in the H4 starches, presumably supported by the small size of the amyloplasts. During storage, the amylopectin skeleton is destabilized by the amorphous areas and the grains become larger; see Table 10 and Figures 9F. Together the low temperature values from H3P4 to H1P4 are achieved, with the H2P4 strengths having the best characteristics (possibly because of starch grains that swell even at low temperatures). In the step from H4P4 to H3P4 changes in long term stability may change due to growth conditions and/or size of tubers. These changes were at maximum 251 Pa and at minimum 62,4 Pa.

Due to cultivation differences in the field (plants grown from tubers) and in the greenhouse (GH, tissue culture plants transferred to greenhouse, limited volume of cultivation pots) the results may differ as can be seen in the "overlap" regions as evident from the Tables 7 to 12 and shown in Figure 9. However, as can be seen from comparison of the data obtained for starch of plants grown in both the field and greenhouse, H4P4 and H3P4 the relative changes in H- and P allele dosages and effect on amylose content and other starch characteristics substantially remains the same. For example, in Table 8 the mean value for the viscosity onset temperature of starch obtained from a H4P4 plant grown in the field and GH differs by about 5°C (61,9 v.v. 66,7) while the difference in the onset temperature of starch from H4P4 and H3P4 within the group of field grown and GH plants remains at about -3°C (61,9 v.v. 58,7 and 66,7 v.v. 63,1) but also remains different in terms of the absolute mean values. A similar variation and relation can be seen for particle size in Table 10, phosphate content in Table 11, and long term stability in Table 12. On the other hand, as shown in Table 7 the values for apparent amylose content and in Table 9 for gel transparency (at least for the H3P4 plant) do not significantly differ.

Therefore, despite the variation of absolute values for some starch characteristics and for some genotypes starch of potato plants of the present invention can be nevertheless clearly identified against starch from H0R0, H4P0 and H0P4 plants by comparing any one of those characteristics which are not substantially influenced by cultivation and/or those which remain different in absolute terms and/or of course by combination of one or more characteristics selected from apparent amylose content, viscosity, gel transparency, long term gel stability, shape, presence or absence of fissures and/or size of starch granules and phosphate content.

In the claims, the values for the starch characteristics of the H4 genotype including H4P4 as well as for H3P4 and the wild type H0R0 plant are based on the values measured for starch from plants grown in the field and for the remaining P4 genotype as well as for the intermediate H2P2 for plants grown in the greenhouse (GH). In case of overlap of the max./min. values indicated for genotypes of the present invention and H0R0, H4P0 and/or H0P4 in the Tables and the corresponding ranges given in the claims, respectively, the mean value is preferably used for the corresponding starch characteristic ± 1%, 2%, 3%, 4%, or 5% but preferably still higher or lower than the maximum and minimum value, respectively, of the corresponding starch characteristic of a H0R0, H4P0 and/or H0P4 plant or in case of overlap of the range given in the claim only, the actual max./min values as measured and indicated in the Tables may be used as the upper and lower values of a claimed range. In addition, or alternatively, in case of an overlap of the ranges for a starch characteristic indicated for a genotype of the present invention and H0R0, H4P0 and/or H0P4 in only the max. or min. value, while the actual values are different altogether the value of overlap may be regarded to be excluded for the range indicated for the genotype of the present invention.

For example, in Table 8 the claimed range for the viscosity onset temperature of starch obtained from a H4P3 plant of the present invention and H4P4 plant both grown in the field are given with 57°C -60°C and 60°C -64°C, respectively, and thus an overlap in the value of 60°C while the actual min. and max. values significantly differ; see 58,3°C and 59°C compared to 60,8°C and 63°C. Accordingly, the value of 60°C may not be regarded as included in the upper range indicated for the H4P3 plant of the present invention but 59,9°C and less until low to 57°C.

In case of the data for the characteristics of starch obtained from H2P2 potato plants, which have been obtained for greenhouse plants only, the values may be normalized against the corresponding data for starch obtained from H4P4 and/or preferably H3P4 potato plants grown in the field and in the greenhouse. For example, regarding the values given for long term stability in Table 12, the max/min values and/or mean value for H2P2 may be normalized for values expected for field grown plants by the difference seen for the corresponding mean values indicated for the H3P4 plants, e.g. 104,5 (field) vs. 243 (GH). Thus, the mean value for long term stability of H2P2 grown in the field may be calculated from 253 given for greenhouse (GH) to be similar and to amount to about 110 Pa.

Regarding most of the analyzed properties, besides the unexpected joint characteristics of starch obtained from H3P4 potato plants (and from H1P4 and H2P4 potato plants too) as well as the H4P2 potato plants the most surprising results have been obtained for starch from the "double intermediate" genotype, i.e. H2P2 potato plants, which most likely will also substantially hold true for starch from other intermediate genotypes, i.e. H1P2, H2P1, H1P3, H3P1, H2P3 and H3P2 potato plants. Thus, though functional alleles of gbssl (H) and ssIII (P) genes - even the same copy number - are present in the plant and should be expected to be dominant over the inactive alleles the properties of the starch obtained from intermediate genotypes such as the H2P2 potato plants is substantially different from starch obtained from wild type H0R0 potato plants.

Claims

1. A Solanum plant, plant part, or plant cell comprising (i) at least one inactive allele of at least a first and second gene endogenous to said plant, plant part, or plant cell, each encoding an enzyme involved in starch synthesis, and (ii) at least one functional allele of said at least first and second endogenous gene.

2. The plant, plant part, or plant cell of claim 1, wherein at least one, preferably all of the inactive alleles is/are due to a missense or nonsense mutation, or silent mutation at the splice donor or acceptor site in said at least first and/or second endogenous gene.

3. The plant, plant part, or plant cell of claim 1 or 2, wherein the first gene is the granule- bound starch synthase I gene ( gbssl, H) and the second gene is a further starch synthase gene (ss), preferably the soluble starch synthase III gene ( ssIII , P).

4. The plant, plant part, or plant cell of claim 3, wherein said inactive allele of gbssl is due to at least one mutation in the gbssl sequence (accession number X58453), preferably at

(i) nucleotide position G1372, preferably G->A leading to an amino acid substitution in the amino acid sequence of GBSSI (accession number Q00775) at position GlylOO to Asp, and/or

(ii) nucleotide position G1407, preferably G->A leading to mis-splicing of the primary transcript; and/or

wherein the inactive allele of ss is due to at least one mutation in the ss sequence, preferably in ssIII cDNA sequence (accession number X95759), preferably at

(iii) nucleotide position G1849, preferably G->A leading to conversion of codon TGG (Trp569 in the amino acid sequence of SSIII (accession number CAA64173) into the stop codon TGA; and/or

(iv) nucleotide position C2144, preferably a C->T transition leading to conversion of codon CAG (Gln668 in the amino acid sequence of SSIII (accession number CAA64173) into the stop codon TAG,

preferably wherein the plant is heterozygous for at least two mutations in gbssl and/or ss.

5. The plant, plant part, or plant cell of any one of claims 1 to 4, wherein the Solanum plant, plant part, or plant cell is a S. tuberosum plant, plant part, or plant cell and quadruplex (4) for the inactive allele of gbssl (H4) and simplex (1), duplex (2) or triplex (3) for the inactive allele of ss, preferably ssIII (Pl, P2, P3); quadruplex (4) for the inactive allele of ss, preferably ssIII (P4) and simplex (1), duplex (2) or triplex (3) for the inactive allele of gbssl (Hl, H2, H3); or duplex (2) for the inactive allele of gbssl (H2) and duplex (2) for the inactive allele of ss, preferably ssIII (P2).

6. The plant, plant part, or plant cell of any one of claims 1 to 5, preferably potato tuber which gives rise to starch which is different in its physicochemical characteristics from starch from a corresponding wild type plant, plant part, or plant cell which is nulliplex (0) for the inactive allele of gbssl and ss, preferably ssIII (H0R0) and/or from a plant which is nulliplex and/or quadruplex for the inactive allele of gbssl and ss, preferably ssIII (H4P0, H0P4, H4P4) or otherwise equivalently lacking GBSSI and/or SSIII activity, preferably wherein the starch is different at least in terms of one or more of

(i) apparent amylose content,

(ii) viscosity,

(iii) gel transparency,

(iv) long term gel stability,

(v) shape and/or size of starch granules,; and/or

(vi) phosphate content.

7. The plant, plant part, or plant cell of claim 6, which gives rise to starch characterized by (i) being obtainable from a H4P1, H4P2 or H4P3 potato plant, preferably having

(al) an apparent amylose content which is lower in comparison to the apparent amylose content of starch derived from a H0R0 potato plant and higher in comparison to the apparent amylose content of starch derived from a H4P4 potato plant, wherein the apparent amylose content is between about 1.0% and 1.5% [H4P1], 0% and 1% [H4P2] or -0.5% and 2% [H4P3] in comparison to 11% to 18% of starch derived from a H0R0 potato plant and to -1% to -3% of starch derived from a H4P4 potato plant;

(bl) a viscosity onset temperature which is higher in comparison to the viscosity onset temperature of starch derived from a H0R0 and a H4P4 potato plant, wherein the viscosity onset temperature is between about 66°C and 67°C [H4P1], 64°C and 66°C [H4P2] or 64°C and 69°C [H4P3] in comparison to 60°C to 64°C of starch derived from a H0R0 and a H4P4 potato plant; (cl) a gel transparency which is in average higher in comparison to the gel transparency of starch derived from a H0R0 and a H4P0 potato plant and lower in comparison to the gel transparency of a starch derived from a H4P4 potato plant, wherein the transmission of the gel is between about 38% and 47% [H4P1], 46% and 62% [H4P2] or 48% and 73% [H4P3] in comparison to between 0.5% to 1.5% and 23% to 42% of starch derived from a H0R0 potato plant and a H4P0 potato plant, respectively, and to 61% to 72% of starch derived from a H4P4 potato plant;

(dl) a long term gel stability which is higher in comparison to the stability of a starch gel derived from a H0R0 potato plant, wherein the difference in the storage modulus being measured during the shearing of the starch gel is between about -1.5 Pa and 3 Pa [H4P1, H4P2, H4P3] in comparison to 35 Pa to 110 Pa as determined for the starch gel derived from a H0R0 plant;

(el) an average relative particle size (d50) which is in average lower in comparison to the relative particle size of starch derived from a H0R0 and a H4P0 potato plant and higher in comparison to the average particle size of a starch derived from a H4P4 potato plant, wherein the particle size is between about 43 pm and 49 pm [H4P1 and H4P2] or 36 pm and 45 pm [H4P3] in comparison to 49 pm to 55 pm and 49 pm to 62 pm of starch derived from a H0R0 potato plant and a H4P0 potato plant, respectively, and to 25 pm to 37 pm of starch derived from a H4P4 potato plant; and/or (fl) a phosphate content which is lower in comparison to the phosphate content of starch derived from a H4P4 potato plant, wherein the phosphate content is between about 850 ppm and 1000 ppm [H4P1], 700 ppm and 1100 ppm [H4P2] or 550 ppm and 1100 ppm [H4P3] in comparison to about 950 ppm to 1350 ppm of starch derived from a H4P4 potato plant,

(ii) being obtainable from a H1P4, H2P4 or H3P4 potato plant, preferably having

(a2) an apparent amylose content which is higher in comparison to the apparent amylose content of starch derived from a H4P4 and/or a H4P0 potato plant and preferably lower than of starch derived from H0P4, wherein the apparent amylose content is between about 16,5% and 20,5% [H1P4], 16% and 20% [H2P4], 11% and 16% [H3P4] in comparison to -1% to -3% of starch derived from a H4P4, 0% to 3% of starch derived from a H4P0 and/or to 18% to 20% of starch derived from a H0P4 potato plant; (b2) a viscosity onset temperature which is lower in comparison to the viscosity onset temperature of starch derived from a H0R0, H4P0 and/or H4P4 potato plant, wherein the viscosity onset temperature is between about 57°C and 60°C in comparison to 60°C to 64°C of starch derived from a H0R0 and a H4P4 potato plant and to 64°C to 69°C of starch derived from a H4P0 potato plant,

(c2) a gel transparency which is lower in comparison to the gel transparency of starch derived from a H4P0 and/or a H4P4 potato plant, wherein the transmission of the gel is between about 1% and 2% in comparison to 23% to 42% and 61% to 72% of starch derived from a H4P0 potato plant and a H4P4 potato plant, respectively;

(d2) a long term gel stability which is lower in comparison to the stability of a starch gel derived from a H4P0 and/or a H4P4 potato plant, wherein the difference in the storage modulus being measured during the shearing of the starch gel is between about 55 Pa and 165 Pa in comparison to -1 Pa to 5 Pa as determined for the starch gel derived from a H4P0 and/or to -1.5 Pa to 2 Pa as determined for the starch gel derived from a H4P4 potato plant;

(e2) starch granules having an average relative particle size (d50) which is in average lower in comparison to the relative particle size of starch derived from a H0R0 and a H4P0 potato plant and higher in comparison to the average particle size of a starch derived from a H4P4 potato plant, wherein the particle size is between about 30 pm and 39 pm in comparison to 49 pm to 55 pm and 49 pm to 62 pm of starch derived from a H0R0 potato plant and a H4P0 potato plant, respectively, and to 25 pm to 37 pm of starch derived from a H4P4 potato plant, and said granules having fissures; and/or (f2) a phosphate content which is higher in comparison to the phosphate content of starch derived from a H4P0 potato plant, wherein the phosphate content is between about 950 ppm and 1300 ppm in comparison to about 500 ppm to 950 ppm of starch derived from a H4P0 potato plant, or

(iii) being obtainable from a H2P2 potato plant, preferably having

(a2) an apparent amylose content which is higher in comparison to the apparent amylose content of starch derived from a H4P4 and/or H4P0 potato plant and preferably lower than of starch derived from H0P4, wherein the apparent amylose content is between about 15% and 18% in comparison to - 1% to -3% of starch derived from a H4P4, 0% to 3% of starch derived from a H4P0 and/or to 18% to 20% of starch derived from a H0P4 potato plant;

wherein

(a) the apparent amylose content has been determined by the method of Hovenkamp- Hermelink et al, Potato Research 31 (1988), 241-246;

(b) the viscosity onset temperature has been determined by viscometric analysis of a 4% (w/w) aqueous suspension of starch using a Brabender Viscograph-E with the following program: Start temperature 25°C and 350 cmg, heating up with l.5°C/min to 95°C and hold for 30 min, cool down to 25°C;

(d) the long term gel stability has been determined of a 4% (w/w) viscosity solution of starch using the rheometer MCR 301 of Anton Paar GmbH, wherein G’ was noted at 1.007 Hz and wherein the difference in the storage modulus was calculated via subtracting the storage modulus measured directly after cooking of the starch gel from the storage modulus measured after storage for three weeks at 5°C;

(e) the particle size and form may differ in terms of being substantially globular- and spherical-shaped; oval- or egg-shaped; smooth or with fissures;

(f) the phosphate content has been determined via analysis of a sample containing 0.5 g starch, 6.0 ml distilled water and 3.0 ml 65% nitric acid that has been digested using the Multiwave Go of Anton Paar GmbH using the ICPE 9000 of Shimadzu.

8. The plant, plant part, or plant cell of any one of claims 1 to 7, which is a non-transgenic plant, plant part, or plant cell.

9. The plant, plant part, or plant cell of any one of claims 1 to 8, which is a S. tuberosum, i.e. potato plant, plant part, or plant cell.

10. A method of making starch or a derivative thereof, the method comprising the step of extracting the starch content from the potato plant of any one of claims 1 to 9, optionally further comprising the step of modifying the extracted starch by physical, enzymatic and/or chemical processing in vitro.

11. Starch obtainable from a potato plant of any one of claims 1 to 9 or by the method of claim 10.

12. Starch characterized by one or more of the physicochemical parameters (al) to (fl) or (a2) to (f2) defined in claim 7, preferably by two, more preferably three, most preferably four and advantageously all five parameters.

13. A method of producing a starch based or starch containing product comprising the method of claim 12 or using the starch of claim 11 or 12.

14. A starch based or starch containing product comprising starch of claim 11 or 12 or obtainable by the method of claim 13.

15. Use of a Solanum plant comprising at least one inactive allele of a gene endogenous to said plant, said gene encoding an enzyme involved in starch synthesis for the generation of a plant, plant part, or plant cell of any one of claims 1 to 8 or for the production of starch of claim 12.