MX2007007537A - Plants having increased yield and method for making the same - Google Patents

Abstract

The present invention concerns a method for increasing plant yield in plants grown under non-stress conditions, by preferentially increasing activity in a plastid of an EFTu polypeptide or a homologue thereof. One such method comprises introducing into a plant an EFTu nucleic acid or variant thereof. The invention also relates to transgenic plants having introduced therein an EFTu nucleic acid or variant thereof, which plants have increased yield, particularly increased seed yield, relative to corresponding wild type plants. The present invention also concerns constructs useful in the methods of the invention.

Description

PLANTS THAT HAVE INCREASED PERFORMANCE AND METHOD TO CREATE THEMSELVES The present invention relates generally to the field of molecular biology and relates to a method for increasing the yield of plants in a plant relative to corresponding wild type plants. More specifically, the present invention relates to a method for increasing the yield of plants under non-stress conditions by preferably increasing the activity in a plastid of an EFTu or a homologue thereof. The present invention also relates to plants having activity in a plastid of an EFTu or a homologue thereof, said plants have increased yield under stress-free conditions in correspondence with wild-type plants under comparable conditions. The invention also provides constructs useful in the methods of the invention. The ever-growing world population and weakened supply of arable land available for agricultural research on fuel for agriculture to improve the efficiency of agriculture. Conventional means for crop and horticultural improvements use breeding techniques to identify plants that have convenient characteristics. However, such selective breeding techniques have several drawbacks, namely, that these techniques are usually labor intensive and result in plants that often contain heterogeneous genetic components that do not always result in the passing of convenient features of the plants. mother plants. Advances in molecular biology have allowed man to modify the germ plasm of animals and plants. Plant genetic engineering involves the isolation and manipulation of genetic material (usually in the form of DNA or RNA) and the subsequent introduction of such genetic material into a plant. This technology has the capacity to supply crops or plants that have several economic, agronomic or horticultural features improved, a feature of particular economic interest is the production. Production is usually defined as the production that can be measured of economic value of a crop. This can be defined in terms of quantity and / or quality. The performance depends directly on several factors, for example, the number and size of the organs, the architecture of the plant, (for example, the number of branches), seed production and more. Root development, nutrient absorption and stress tolerance can also be important factors in determining yield. In addition, plant seeds are an important source of human and animal nutrition. Crops such as corn, rice, wheat, sugarcane and soybeans account for more than half of total human caloric consumption, even through direct consumption of the seeds themselves or through the consumption of meat products from processed seeds. They are also a source of sugars, oils and many kinds of metabolites used in industrial processes. The seeds contain an embryo, the source of new shoots and roots after germination and an endosperm, the source of nutrients for embryo growth, during germination and early seedling development. The development of a seed involves many genes, and requires the transfer of metabolites of roots, leaves and stems in the seed of growth. The endosperm, in particular, assimilates the metabolic precursors of carbohydrate polymers, oils and proteins and synthesizes them into storage macromolecules to fill the grain. The ability to increase the yield of plant seeds, either through the increased cultivation index, bulb seed weight increased a thousandfold, number of seeds, seed biomass, seed development, seed filling and any other Seed-related property could have many applications in agriculture, and even many agricultural uses such as in the biotechnological production of substances such as pharmaceuticals, antibodies or vaccines.

It has now been found that the preferably increased activity in a plastid of a translational elongation factor (EFTun) gives plants grown under conditions of increased yield without stress relative to the corresponding wild type plants. In plants, the synthesis of proteins occurs in three sub-cellular compartments, namely the cytoplasm, plastids and mitochondria. The mechanisms responsible for protein synthesis in the cytoplasm, plastids and mitochondria are different among them. The plant cells, therefore, contain three different types of ribosomes, after groups of transfer RNAs (tRNA), and three groups of auxiliary factors for protein synthesis. Plastids and mitochondria are thought to have originated through the endosymbiosis of previous prokaryotic organisms. Consistent with this theory, the synthetic protein machinery in plastids and mitochondria is more closely related to bacterial systems than to the translation apparatus in the cytoplasm of surrounding plant cells. Translational elongation factors (EFTu) are essential components of protein synthesis that play a role in the elongation of polypeptides. EFTu interacts with tRNA and transports codon-specific tRNA to the aminoacyl site on the ribosome (ribosomal site A) during the translational elongation step. EFT is encoded in the chloroplast of lower photosynthetic eukaryotes such as Chlamydomonas and Euglena, whereas in higher plants an evolutionary transfer of these genes occurred from the chloroplast to the nucleus. Several cDNA clones encoding chloroplasts and other EFTus have been identified in a number of higher plants. The published patent application of E.U.A. US 2003/0044972 In the name of Ristic et al., Describes a heat shock protein with high homology to the EFTu chloroplast elongation factor and temporal and spatial expression with high homology of the heat shock protein in an organ or tissue plant to increase heat tolerance and drought in female reproductive organs. Bhadula et al. (Planta (2001) 212: 359-366) shows the synthesis induced by heat stress of EFTu in a heat-tolerant corn line. While it is evident from the foregoing that EFTu plays a protective role during heat stress, it is not evident from the prior art that EFTu could give any beneficial effect under normal or stress-free growth conditions. It has now surprisingly been found that the preferably increased activity in a plastid of an EFTu or a homolog thereof gives plants grown under increased yield of stress-free conditions relative to wild-type plants grown under corresponding conditions. Reference herein to "corresponding wild type plants" means any suitable plant or control plants, the choice of which could be within the capabilities of a person skilled in the art and may include, for example, wild type plants corresponding or corresponding plants without the gene of interest. A "control plant" as used herein refers not only to whole plants, but also to parts of plants, including seeds and seed parts. The reference herein to "stress-free conditions" means growth / cultivation of a plant at any stage in its life cycle (from seed the mature plant and back to seed) under normal growth conditions, including moderate stress each day You find each plant, but that does not include severe stress. In conditions of severe stress, the plant can stop all growth. Moderate stress, on the other hand, is defined in the present by any stress to which a plant is exposed that results in the plant ceasing to grow as a whole without the ability to resume growth. An example of a severe stress that is specifically excluded is at temperatures above 35 ° C in the shade measured by a household thermometer in an instrument shed that is away from materials that can absorb heat and affect an accurate temperature reading of the air. Another example of severe stress that is specifically excluded is drought, which is defined herein as a continuous increase in the degree of dryness over a period of seven days compared to a "normal" or average amount. Said normal or average quantities will vary from region to region. In accordance with the present invention, a method is provided for increasing the yield of plants under stress-free conditions relative to the corresponding wild type plants grown under comparable conditions, comprising activity preferably increasing in a plastid of an EFTu polypeptide or a homologue of the same. Advantageously, the performance of the methods according to the present invention results in plants having increased plant yield, especially increased seed yield. The term "increased yield" as defined herein means an increase in one or more of the following, each relative to the following corresponding wild type plants: (i) increased biomass (weight) of one or more parts of a plant, particularly parts that are above ground (harvestable), increased root biomass or increased biomass from any other harvestable part; (ii) total seed yield, which includes an increase in seed biomass (seed weight) and which may be an increase in seed weight per plant or on an individual seed basis; (iii) increased number of seeds (stuffed); (iv) increased filling regime (which is the number of filled seeds divided by the total number of seeds and multiplied by 100); (v) increased seed size, which may also influence seed composition; (vi) increased seed volume, which can also influence seed composition; (vii) individual seed area increased; (viii) weight of core seed increased a thousand times (PSM), which was extrapolated from the number of full seeds counted and their total weight. An increased PSM may result from an increase in embryo size and / or endosperm size. Taking corn as an example, an increase in yield can be manifested as one or more of the following: increase in the number of plants per hectare or acre, an increase in the number of ears per plant, an increase in the number of rows, number of seeds per row, weight of core seeds, kernel weight increased one thousand times, length / diameter of ears, among others. Taking rice as an example, an increase in yield can be manifested by an increase in one or more of the following: number of plants per hectare or acre, number of panicles per plant, number of ears per panicle, number of flowers per panicle, increase in the seed filling regime, increase in weight of core seeds increased a thousandfold, among others. An increase in performance can also result in the modified architecture, or it can occur as a result of modified architecture. According to a preferred aspect, the performance of the methods according to the present invention results in plants having increased seed yield. Therefore, according to the present invention, there is provided a method for increasing the yield of plant emillas increased in plants grown under stress-free conditions, which method comprises preferably increasing activity in a plastid of an EFTu polypeptide or a homolog of the same. Since the transgenic plants according to the present invention have increased yield these plants probably exhibit an increased growth regime (during at least part of their life cycle), relative to the growth rate of corresponding wild type plants in a corresponding stage in its life cycle. The increased growth regime may be specific to one or more parts of a plant (including seeds) or may be substantially throughout the plant. A plant that has an increased growth regime may exhibit early flowering. The increase in growth regime can take place in one or more stages in the life cycle of a plant or during substantially the entire life cycle of the plant. The regimen of growth during the early stages in the life cycle of a plant may reflect increased vigor. The increase in the growth regime can alter the harvest cycle of a plant allowing the plants to be cut afterwards and / or harvested sooner than would otherwise be possible. If the growth regime is sufficiently increased, it may allow additional seeds of the same plant species to be sown (for example, planting and harvesting rice plants followed by planting and harvesting additional rice plants within a growing period). conventional). Similarly, if the growth regime increases sufficiently, it may allow additional sowing of seeds from different plant species (for example, planting and harvesting of rice plants followed by, for example, planting and optional harvesting of soybeans, potatoes or any other suitable plant). Additional harvest times of the same rhizome in the case of some plants may also be possible. Altering the harvest cycle of a plant can lead to an increase in annual biomass production per acre (due to an increase in the number of times (ie in a year) that any particular plant can develop and be harvested). An increase in the growth regime may also allow the cultivation of transgenic plants in a wider geographical area than their wild type counterparts, since the territorial limits for the development of a crop are often determined by adverse environmental conditions after the time of growth. plantation (early season) or at the time of harvest (late season). These adverse conditions can be avoided if the harvest cycle is shortened. The growth regime can be determined by deriving several parameters of growth curves plotting growth experiments, these parameters can be: T-Mid (the time that the plants take to reach 50% of its maximum size) and T-90 ( time that the plants take to reach 90% of its maximum size), among others. The performance of the methods of the invention gives plants that have an increased growth rate. Therefore, according to the present invention, there is provided a method for increasing the growth rate of plants grown under stress-free conditions, said method preferably comprises increasing activity in a plastid of an EFTU-like polypeptide or a homologue thereof. The growth characteristics mentioned above can be modified salefully in a plant. The term "plant" as used herein encompasses whole plants, ancestors and progenies of plants and parts of plants (such as cell, sprout seeds, stems, leaves, roots, flowers and tubers of plants), tissues and organs, wherein each of those mentioned above comprises the gene / nucleic acid of. The term "plant" also encompasses plant cells, suspension cultures, callus tissues, embryos, meristematic regions, gametophytes, sporophytes, pollen and microspores, again wherein each of those mentioned above comprises the gene / nucleic acid of interest . Plants that are particularly useful in the methods of the invention include algae, ferns and all plants belonging to the Viridiplantae superfamily, in particular monocotyledonous and dicotyledonous plants, including fodder or forage legumes, ornamental plants, food crops, trees or shrubs. selected from the list comprising Acacia spp., Acer spp., Actinidia spp., Aesculus spp., Agathis australis, Albizia amara, Alsophila tricolor, Andropogon spp., Arachis spp., Areca catechu, Astelia fragrans, Astragalus cicer, Baikiaea plurijuga, Betula spp., Brassica spp., Bruguiera gymnorrhiza, Burkea africana, Butea leafy, Cadaba farinosa, Calliandra spp., Camellia sinensis, Canna indica, Capsicum spp. , Cassia spp. , Centroema pubescens, Chaenomeles spp., Cinnamomum cassia, Coffea arabica, Colophospermum mopane, Coronillia varia, Cotoneaster serotina, Crataegus spp., Cucumis spp-, Cupressus sp. , Cyathea dealbata, Cydonia oblonga, Cryptomeria japonica, Cymbopogon spp., Cynthea dealbata, Cydonia oblonga, Monetary Dalbergia, Davallia divaricata, Desmodium spp., Dicksonia squarosa, Diheteropogon amplectens, Dioclea spp, Dolichos spp., Dorycnium rectum, Echinochloa pyramidalis, Ehrartia spp., Eleusine coracana, Eragrestis spp., Erythrina spp., Eucalyptus spp., Euclea schimperi, Eulalia villosa, Fagopyrum spp., Feijoa sellowiana, Fragaria spp., Flemingia spp., Freycinetia banksii, Geranium thunbergii, Ginkgo biloba, Glycine javanica, Gliricidia spp, Gossypium hirsutum, Grevillea spp., Guibourtia coleosperma, Hedysarum spp., Hemarthia altissima, Heteropogon contortus, Hordeum vulgare, Hyparrhenia rufa, Hypericum erectum, Hyperthelia díssoluta, Indigo incamata, Iris spp-, Leptarrhena pyrolifolia, Lespediza spp., Lettuca spp., Leucaena leucocephala, oudetia simplex, Lotonus bainesii, Lotus spp., Macrotyloma axillare, Malus spp., Manihot esculenta, Medicago sativa, Metasequoia glyptostzoboides, Musa sapientum, Nicotianum spp., Onobrychis spp., Omithopus spp., Oryza spp., Peltophoru africanum, Pennisetum spp. Persea gratissima, Petunia spp., Phaseolus spp., Phoenix canariensis, Phormium cookianum, Photinia spp., Picea glauca, Pinus spp., Pisum satiyum, Podocarpus totara, Pogonarthria fleckii, Pogonarthria squarrosa, Populus spp., Prosopis cineraria, Pseudotsuga menziesii, Pterlobium stellatum, Pyrus communis, Quercus spp., Rhaphiolepsis umbellata, Rhopalostylis sapida, Rhus natalensis, Pibes grossularia, Ribes spp., Robinia pseudo acacia, Rosa spp., Rubus spp., Salix spp., Schyzachyrium sanguineum, Sciadopitys verticill Ata, Sequoia sempervirens, Sequoiadendron giganteum, Sorghum bicolor, Spinacia spp., Sporobolus fimbriatus, Stiburus alopecuroides, Stylosanthos humilis, Tadehagi spp, Taxodium distichum, Themeda triandra, Trifolium spp., Triticum spp., Tsuga heterophylla, Vaccinium spp., Vicia spp. ., Vitis vinifera, Watsonia pyramidata, Zantedeschia aethiopica, Zea mays, amaranth, artichoke, asparagus, broccoli, Brussels sprouts, cabbage, cañola, carrot, cauliflower, celery, cabbage, flax, kale, lentil, rapeseed oil, okra , onion, potato, rice, soy, strawberry, beet, sugar cane, sunflower, tomato, pumpkin, tea and seaweed, among others. According to a preferred embodiment of the present invention, the plant is a crop plant such as soybean, sunflower, cañola, alfalfa, rapeseed, cotton, tomato, potato or tobacco. Preferably further, the plant is a monocotyledonous plant, such as sugarcane. More preferably the plant is a cereal, such as rice, corn, wheat, barley, millet, rye, sorghum or oats. The activity of an EFTu polypeptide can be increased by high levels of the polypeptide. Alternatively, the activity may also be increased when there is no change in levels of an EFTu polypeptide, or even when there is a reduction in levels of an EFTu polypeptide. This can occur when the intrinsic properties of the polypeptide are altered, for example, by creating mutant versions that are more active than the wild-type polypeptide. Reference herein to "preferably" increasing activity is taken as a targeted increase in the activity of a polypeptide in a plastid above that found in plastids of wild type plants under stress-free conditions. The activity may preferably be increased in a plastid using techniques well known in the art, such as plastid-directed activity using transit peptide sequences or by transformation of a plastid. The activity can be increased in any plastid, however, the preferably increasing activity in a chloroplast is preferred.

The term "EFTu (polypeptide) or a homologue thereof" as defined herein, refers to a polypeptide comprising: (i) the following GTP binding domains in any order GXXXXGK and DCXXG NKXD and S / L / K / QA / GL / V / F, where X is any amino acid; and (ii) EFTu domain ALMANPAIKR or a domain that has a growing identity preference order of at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95% of it and / or KD / GS / A. An "EFTu polypeptide or a homologue thereof" can be easily identified using routine techniques well known in the art. The reasons defined above are highly conserved, thus allowing a person skilled in the art to easily identify EFTu sequences that are within the above definition. The plant EFTu polypeptide sequence represented by SEQ ID NO: 2, encoded by the nucleic acid of SEQ ID NO: 1, was found on the basis of homology to a transcription factor in Drosophila. Examples of polypeptides derived from plants that are under the definition of an "EFTu or a homologue thereof" include: SEQ ID NO: 4 of Nicotiana tabacum; SEQ ID NO: 6 of Arabidopsis thaliana; SEQ ID NO: 8 of Nicotiana sylvestris; SEQ ID NO: 10 a translational elongation factor of rice chloroplasts; SEQ ID NO: 12 a mitochondrial elongation factor of Arabidopsis thaliana; SEQ ID NO: 14 a mitochondrial elongation factor of Arabidopsis thaliana; SEQ ID NO: 16 of Oryza sativa; SEQ ID NO: 18 by Zea Mays (encoded by a nuclear gene for a mitochondrial product); SEQ ID NO: 20 from Arabidopsis thaliana; and SEQ ID NO: 22 Synechocystis. The following table shows the percentage of homology of several sequences of EFTu polypeptides compared to the amino acid sequence represented by SEQ ID NO: 2 based on general overall sequence alignment. The percentage of identity was calculated using an alignment program with default parameters.

Table 1: Homology of protein sequences similar to EFTU with SEQ ID NO: 2 based on global sequence alignment An analysis can also be carried out to determine the activity of EFTu. A first step could involve isolating plastids (for example chloroplasts), followed by obtaining purified EFTu for the determination of the specific activity (GDP exchange). A person skilled in the art could easily be layers of plastid isolating using techniques well known in the art. For an example of chloroplast isolation, see Olsson et al., (J Biol Chem. 2003 Nov 7: 278 (45): 44430-47). Similarly, someone skilled in the art could also be able to purify EFTu easily. As an example, see Stanzel et al., (Eur J Biochem, 1994 Jan 15: 219 (1-2): 435-9) for a method for the purification of total EFTu. In addition, someone skilled in the art can also determine the specific activity of EFTu. See for example Zhang et al., (J. Bacteriol., 176, 1184-1187) for an exchange analysis of [3 H] GDP for the determination of recombinant pre-EFTu activity. It should be understood that sequences that are under the definition of "EFTu polypeptide or homologue thereof" are not limited to the sequences represented by SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, SEQ ID NO. : 8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 14, SEQ ID NO: 16, SEQ ID NO: 18, SEQ ID NO: 20 and SEQ ID NO: 22, but that any polypeptide that meets the criteria for reasons comprising the motifs: (i) the following GTP binding domains in any order GXXXXGK and DXXG and NKXD and S / L / K / QA / GL / V / F, where X is any amino acid; and (ii) the EFTu domain ALMANPAIKR or a domain having 50% identity thereto and / or K D / G EE S / A may be suitable for use in the methods of the invention. The nucleic acid encoding an EFTu polypeptide or a homologue thereof can be any natural or synthetic nucleic acid. An EFTu polypeptide or a homologue thereof as defined above is one that is encoded by a nucleic acid / EFTu gene. Thus, the term "nucleic acid / EFTu gene" as defined herein is any nucleic acid / gene encoding a EFTu-like polypeptide or a homologue thereof as defined above. Examples of EFTU nucleic acids include those represented by any of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, SEQ ID NO: 7, SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 15, SEQ ID NO: 17, SEQ ID NO: 19 and SEQ ID NO: 21. Nucleic acid / EFTu genes and variants thereof may be suitable for practicing the methods of the invention . The EFTu nucleic acid / gene variant includes portions of a nucleic acid / EFTu gene and / or nucleic acids capable of hybridizing with a nucleic acid / EFTu gene.

The terminal portion as defined herein refers to a piece of DNA comprising at least sufficient nucleotides to encode a protein that compresses: (i) the following GTP binding domains in any order GXXXXGK and DXXG and NKXD and S / L / K / QA / GL / V / F, where X is any amino acid; and (ii) the EFTu domain ALMANPAIKR or a domain that has 50% identity to it and / or K D / G EE S / A. A portion may be prepared, for example, by performing one or more deletions to an EFTu nucleic acid. The portions can be used in isolation or can be fused to other coding sequences (or without coding) in order, for example, to produce a protein that combines several activities. When fused to other coding sequences, the resulting polypeptide produced by translation could be larger than that predicted for the EFTu fragment. Preferably, the functional portion is a portion of a nucleic acid represented by any of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, SEQ ID NO: 7, SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 15, SEQ ID NO: 17, SEQ ID NO: 19 and SEQ ID NO: 21. Another variant nucleic acid / EFTu gene is a nucleic acid capable of hybridizing under restriction sites, preferably under restriction conditions, with a nucleic acid / EFTu gene as defined above, whose hybridization sequence encodes a polypeptide comprising: (i) the following GTP binding domains in any order GXXXXGK and DXXG and NKXD and S / L / K / QA / GL / V / F, where X is any amino acid; and (ii) the EFTu domain ALMANPAIKR or a domain that has 50% identity to it and / or K D / G EE S / A. Preferably, the hybridization sequence is one that can hybridize to a nucleic acid as represented by any of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, SEQ ID NO: 7, SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 15, SEQ ID NO: 17, SEQ ID NO: 19 and SEQ ID NO: 21 or a portion of any of the above sequences as defined above . The term "hybridization" as defined herein is a process wherein the substantially homologous complementary nucleotide sequences are fused together. The hybridization process can occur completely in solution, that is, both nucleic acids are in solution. The hybridization process can also occur with one of the complementary nucleic acids immobilized to a matrix such as magnetic beads, Sepharose beads or any other resin. The hybridization process can additionally occur with one of the complementary nucleic acids immobilized to a solid support such as a nitrocellulose or nylon membrane or immobilized for example, by photolithography for, for example, a silicon glass support (the latter known as arrays of nucleic acids or micro arrays or as small pieces of nucleic acids). In order to allow hybridization to occur, the nucleic acid molecules are generally thermally or chemically denatured to fuse a double strand into two single strands and / or to remove pins and other secondary structures of single-stranded nucleic acids. Hybridization severity is influenced by conditions such as temperature, salt concentration, ionic strength and regulatory hybridization composition. "Severe hybridization conditions" and "stringent hybridization washing conditions" in the context of nucleic acid hybridization experiments such as Southern and Northern hybridizations depend on the sequences and are different under different environmental parameters. The expert is aware of several parameters that can be altered during hybridization and washing and which will maintain or change severe conditions. The Tm is the temperature under defined ionic strength and pH, in which 50% of the target sequence is hybridized to a perfectly matched probe. The Tm depends on the solution conditions and the base composition and length of the probe. For example, longer sequences hybridize specifically at higher temperatures. The maximum rate of hybridization is obtained from approximately 16 ° C to 32 ° C below the Tm. The presence of monovalent cations in the hybridization solution reduces the electrostatic repulsion between the two strands of nucleic acids thus promoting the formation of hybrids; the effect is visible for sodium concentrations up to 0.4 M. Formamide reduces the DNA-DNA fusion temperature and DNA-RNA duplexes with 0.6 to 0.7 ° C for each percentage of formamide, and the 50% addition of formamide allows hybridization to take place at 30 to 45 ° C, although the rate of hybridization will be lowered. Base pair differences reduce the rate of hybridization and the thermal stability of the duplexes. On average and for large probes, the Tm decreases approximately 1 ° C per% of different base. The Tm can be calculated using the following equations, depending on the types of hybrids: 1. DNA-DNA hybrids (Meinkoth and Wahl, Anal. Biochem., 138: 267-284, 1984): Tm = 81.5 ° C + 16.6 xlog [ Na +] a + 0.41 x% [G / Cb] - 500 x [Lc] _1-0.61 x% formamide 2. DNA-RNA or RNA-ARNb hybrids: Tm = 79.8 + 18.5 (logi0 [Na +] a) + 0.58 (% G / Cb) + 11.8 (% G / Cb) 2 - 820 / Lc 3. Oligo-DNA or oligo-ARNd hybrids: For < 20 nucleotides: Tm = 2 (In) For 20-35 nucleotides: Tm = 22 + 1.46 (In) ao for another monovalent cation, but only accurate on the scale of 0.01-0.4 M. b only required for% GC on the scale from 30% to 75%. CL = double length in base pairs. d Oligo, oligonucleotide; In, effective length of initiator = 2x (not of G / C) + (not of A / T). Note: for each 1% of formamide, the Tm is reduced approximately 0.6 to 0.7 ° C, while the presence of 6M urea reduces the Tm by approximately 30 ° C. Hybridization specificity is usually the function of subsequent hybridization washes. To remove the background that results from non-specific hybridization, samples are washed with diluted salt solutions. Critical factors for such washes include the ionic strength and temperature of the final wash solution: the lower the salt concentration and the higher the wash temperature, the greater the wash severity. Washing conditions are normally carried out at or below the hybridization severity. Generally, severe conditions suitable for nucleic acid hybridization analysis or gene amplification detection methods are as shown above. You can select more or less severe conditions. Generally, conditions of low stringency are selected to be about 50 ° C lower than the melting point term (Tm) for the specific sequence at a defined ionic strength and pH. The conditions of medium severity are when the temperature is 20 ° C below the Tm and the conditions of high severity are when the temperature is 10 ° C below Tm. For example, severe conditions are those that are at least as severe as, for example, A-L conditions; and the conditions with reduced severity are at least as severe as, for example, the conditions of M-R. The non-specific binding can be controlled using any of a number of known techniques such as, for example, blocking the membrane with protein-containing solutions, RNA additions, heterologous DNA, and SDS to the regulatory solution of hybridization and RNase treatment. Examples of hybridization and washing conditions are listed in Table 2 below.

Table 2: Examples of hybridization and washing conditions F "Hybrid length" is the anticipated length for the hybridizing nucleic acid. When the nucleic acids of known sequence are hybridized, the hybrid length can be determined by aligning the sequences and identifying the conserved regions described herein.

† SSPE (IxSSPE is NaCl 0.15M, Na¾P04 lOmM, and EDTA 1.25 mM, pH 7.4) can be replaced by SSC (lxSSC is 0.15M NaCl and 15m sodium citrate) in the buffering and washing buffer solutions; the washes are performed for 15 minutes after the hybridization is finished. Hybridizations and further washings may include 5x Denhardt's reagent, 0.5-1.0% SDS, 100 pg / ml denatured fragmented salmon sperm DNA, 0.5% sodium pyrophosphate, and up to 50% formamide. * Tb-Tr: Hybridization temperature for hybrids anticipated to be less than 50 base pairs in length could be 5-10 ° C lower than the melting temperature Tm of the hybrids; Tm is determined according to the equations mentioned above. * The present invention also encompasses the substitution of any one or more pairs of DNA or RNA hybrids with either a PNA or a modified nucleic acid. In order to define the level of severity, one can conveniently refer to Sambrook et al. (2001) Molecular Cloning: a laboratory manual, 3a. Cold Spring Harbor Laboratory Press, CSH, New York or Current Protocols in Molecular Biology, John Wiley & Sons, N.Y. (1989). The EFTu nucleic acid or variant thereof can be derived from any natural or artificial source. This nucleic acid can be modified from its native form in composition and / or genomic environment through deliberate human manipulation. The nucleic acid is of prokaryotic or eukaryotic origin, from a microbial source, such as yeast or fungus, or from a source of plant, algae or animal (including human). Preferably the nucleic acid is of eukaryotic origin. The nucleic acid is also preferably of plant origin, either from the same plant species (for example to one to be introduced) or from a different plant species. The nucleic acid can be isolated from a dicotyledonous plant, preferably from the family Solanaceae, more preferably from the genus Nicotianae, more preferably from tobacco. Even more preferably, the EFTu nucleic acid isolated from tobacco is represented by SEQ ID NO: 1 and the amino acid sequence of EFTu is as represented by SEQ ID NO: 2. The nucleic acid of plant origin is preferably a nucleic acid. plastidic (that is, derived from a plastid). Plastidic nucleic acids have a closer relationship to bacterial nucleic acids than non-plastid nucleic acids. Therefore, the invention can also be carried out using bacterial EFTu nucleic acids or variants thereof. The bacterial nucleic acids are directed to a plastid, preferably a chloroplast. In addition, mitochondria also share a common origin to plastid or bacterial nucleic acids and therefore the invention can also be carried out using a mitochondrial EFTu nucleic acid or variant thereof which may be of animal or fungal origin. The mitochondrial nucleic acids are directed to a plastid, preferably a chloroplast. Despite being closely related to a plastidic nucleic acid than Bactrian or mitochondrial nucleic acid, a cytosolic nucleic acid may also be suitable for use in the methods of the invention while the nucleic acid is directed to a plastid, preferably a chloroplast. Methods for targeting plastids are well known in the art and include the use of transit peptides. The following Table 3 shows examples of transit peptides that can be used to direct any EFTu protein to a plastid, whose EFTu is not, in its natural form, normally directed to a plastid, or whose EFTu is its natural form is directed to a plastid by virtue of a different transit peptide (for example, its natural transit peptide).

Table 3: Examples of transit peptide sequences useful for targeting amino acids to plastids The activity of an EFTu polypeptide or a homologue thereof can be increased by introducing a genetic modification (preferably at the site of an EFTu gene). The site of a gene as defined herein means a genomic region, which includes the gene of interest and 10 KB upstream or downstream of the coding region. Genetic modification can be introduced, for example, by one (or more) of the following methods: T-DNA activation, TILLING, site-directed mutagenesis, directed evolution, homologous recombination and introducing and expressing in a plant cell a nucleic acid that encodes an EFTu polypeptide or a homologue thereof (the product of the gene can then be directed to a plastid in the plant cell, unless the gene being expressed is a plastidic gene). After the introduction of the genetic modification, a selection step for the increasing activity of an EFT polypeptide follows, whose increase in activity gives plants that have increased yield. The T-DNA activation tag (Hayashi et al., Science (1992) 1350-1353) involves the insertion of T-DNA usually containing a promoter (it may also be a translational enhancer or an intron), in the genomic region of the gene of interest or 10 KB upstream or downstream of the coding region of a gene in a configuration such that the promoter directs the expression of the targeted gene. Normally, the regulation of expression of the target gene by its natural promoter is interrupted and the gene falls under the control of the newly introduced promoter. The promoter is normally included in a T-DNA. This T-DNA is randomly inserted into the genome of the plant, for example, through infection with Agrobacterium and leads to over-expression of genes near the inserted T-DNA. The resulting transgenic plants show dominant phenotypes due to over-expression of genes near the introduced promoter. The promoter that will be introduced can be any promoter capable of directing the expression of a gene in the desired organism, in this case a plant. For example, constitutive, tissue-preferred promoters of the preferred and inducible cell type are all suitable for use in T-DNA activation. The use of a seed-specific promoter, more particularly a specific embryo promoter and / or is preferred. ailerons. A genetic modification can also be introduced into the site of a gene encoding an RNA binding protein using the TILLING technique (Local Induced Lesions Targeted to White IN Genomes). This is a mutagenesis technology useful to generate and / or identify, and to eventually isolate the mutagenized variants of an EFTu nucleic acid capable of exhibiting EFTu activity. TILLING also shows a selection of plants that carry these mutant variants. These mutant variants may still exhibit higher EFTu activity than that exhibited by the gene in its natural form. TILLING combines high density mutagenesis with high performance screening methods. The steps normally followed in TILLING are: (a) mutagenesis of EMS (Redei and Koncz, 1992, Feldman and others, 1994, Lightner and Caspar, 1998); (b) DNA preparation and combination of individuals; (c) PCR amplification of a region of interest; (d) denaturation and pairing to allow the formation of heteroduplex; (e) CLFDH, wherein the presence of a heteroduplex in a combination is detected as an extra peak in the chromatogram; (f) identification of the imitating individual; and (g) sequencing of the mutant PCR. Methods for TILLING are well known in the art (McCallum Nat Biotechnol, 2000 Apr; 18 (4): 455-7, reviewed by Stemple 2004 (TILLING-a High-throughput harvest for functional genomics Nat. Rev. Genet 2004 Feb; 5 (2): 145-50)). Site-directed mutagenesis can be used to generate amino acid variants of EFTu. Several methods are available to achieve site-directed mutagenesis, the most common being RCP-based methods (Current protocols in molecular biology, Willey Eds. Http: //www.4ulr, com / products / currentprotocols / index.html). Directed evolution (or gene switching) can also be used to generate EFTu nucleic acid variants. This consists of reiterations of the DNA changes followed by appropriate screening and / or selection to generate and identify variants having a modified biological activity (Castle et al., (2004) Science 304 (5674): 1151-4; US patents 5,811,238; and 6,395,547). The activation of T-DNA, TILLING, site-directed mutagenesis and directed evolution are examples of technologies that allow the generation of novel alleles and variants of EFTu. Homologous recombination allows the introduction into a genome of a selected nucleic acid at a defined selected position. Homologous recombination is a normal technology routinely used in biological sciences for lower organisms such as yeast or Physcomitrella moss. Methods for performing homologous recombination in plants have been described not only for model plants (Offringa et al. (1990) EMBO J 9 (10): 3077-8) but also for crop plants, for example, rice (Terada, and others, (2002) Nat Biotech 20 (10): 1030-4 / Lida and Terada (2004) Curr Opin Biotech 15 (2): 132.8). The nucleic acid to be targeted (which may be a EFTu nucleic acid or variant thereof as defined above) is directed to the site of an EFTu gene. The nucleic acid to be targeted may be an improved allele used to replace the endogenous gene or it may also be introduced into the endogenous gene. According to a preferred embodiment of the invention, the yield of plants can be increased in plants grown under stress-free conditions by introducing and expressing in a plant, plant part or plant cell a nucleic acid encoding an EFTu polypeptide or a homologue thereof. same. The polypeptide can then be directed to a plastid in the plant cell, unless the gene being expressed is a plastidic gene. An EFTu polypeptide or a homologue thereof as mentioned above is one comprising: (i) the following GTP binding domains in any order GXXXXGK and DXXG and NKXD and S / L / K / QA / GL / V / F , where X is any amino acid; and (ii) the EFTu domain ALMANPAIKR or a domain that has 50% identity to it and / or K D / G EE S / A. The nucleic acid to be introduced into a plant can be a full-length nucleic acid or it can be a portion or a hybridization sequence as defined above. "Homologs" of a protein encompass peptides, oligopeptides, polypeptides, proteins and enzymes that have substitutions, deletions and / or amino acid insertions in relation to the unmodified protein in question and that have biological and functional activity similar to that of the non-protein. modified from which they are derived. To produce such homologs, the amino acids of the protein can be replaced by other amino acids that have similar properties (such as hydrophobicity, hydrophilicity, antigenicity, propensity to form or break a-helical structures or similar β-lamellar structures). Conservative substitution tables are well known in the art (see for example Creighton (1984) Proteins, W.H. Freeman and Company and Table 1 above). According to a preferred aspect of the invention, the homologue has an increasing order of sequence identity preference of 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95% to the amino acid sequence represented by SEQ ID NO: 2. If a polypeptide has at least 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80% identity , 85%, 90%, the amino acid represented by SEQ ID NO: 2 can be easily established by sequence alignment. Methods for sequence alignment for comparison are well known in the art, such methods include GAP, BESTFIT, BLAST, FASTA and TFAS A. GAP uses the algorithm of Needleman and Wunsch (J. Mol. Biol. 48: 443-453; 1970) to find the alignment of two complete sequences that maximizes the number of combinations and minimizes the number of spaces. The BLAST algorithm calculates the percentage of sequence identity and performs a statistical analysis of the similarity between the two sequences. The software to carry out the BLAST analysis is publicly available through the National Center for Biotechnology Information. An EFTu polypeptide or a homologue thereof having at least 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% identity to the amino acid represented by SEQ ID NO: 2 can be easily identified by alignment of a search sequence (preferably a protein sequence) with known EFTu protein sequences (see for example the alignment shown in Figure 1). The search sequence can be aligned (with sequences similar to known EFTUs) using, for example, the AlignX VNTI multiple alignment program, based on a modified grouped W algorithm (InforMax, Bethesda, MD, http://www.informaxinc.com ), with the default configuration for the penalty of opening free spaces of 10 and an extension of free spaces of 0.05. Also encompassed by the term "homologs" are two special forms of homology, which include sequences of orthologous sequences of paralogs, which encompass evolutionary concepts used to describe ancestral relationships of genes. The term "paralogs" refers to gene duplications within the genome of a species leading to paralogical genes. The term "orthologs" refers to homologous genes in different organisms due to the species. Orthotists, for example, in species of monocotyledonous plants, can easily find themselves performing a reciprocal expansive research, so-called. This can be done by a first expansion involving the expansion of the sequence in question (eg, SEQ ID NO: 1 or SEQ ID NO: 2) against any sequence database, such as the publicly available NCBI database that is You can find it at http: // www. ncbi. nlxn nih, gov. BLASTN or TBLASTX (using normal default values) can be used when starting from a sequence of proteins and BLASTP or BLAS N (using normal defaults) when starting from a protein sequence. Optionally, BLAST results can be filtered. The full-length sequences of the filtered results or the unfiltered results are resubmitted to BLAST (second BLAST) against the sequences of the organism from which the sequence in question is derived (where the sequence in question is SEQ ID NO: 1 or SEQ ID NO: 2, the second BLAST could therefore be against tobacco sequences). Then the results of the first and second BLAST are compared. A paralog is identified if a high-rank point of the second BLAST is of the same species from which the sequence in question is derived; an orthologous is identified if a high-rank point of the second BLAST is not of the same species from which the sequence in question is derived. Higher rank points are those that have a low value of E. While the value E is lower, the classification is more important (or in other words, the opportunity of finding the point is less). The calculation of the E value is well known in the art. In the case of large families, ClustalW can be used, followed by a neighboring binding tree, to help visualize the grouping of related genes and identify orthologs and paralogs. A homolog can be in the form of a "substitution variant" of a protein, i.e., wherein at least one residue in an amino acid sequence has been removed and a different residue has been inserted in its place. Amino acid substitutions are usually residues alone, but may be grouped depending on the functional constraints placed on the polypeptide; the insertions will usually be in the order of approximately 1 to 10 amino acid residues. Preferably, amino acid substitutions comprise conservative amino acid substitutions. A homolog can also be in the form of an "insertion variant" of a protein, i.e., where one or more amino acid residues are introduced at a predetermined site in a protein. The inserts may comprise amino terminal and / or carboxy terminal fusions as well as insertions between the single or multiple amino acid sequences. Generally, insertions within the amino acid sequence will be smaller than amino or carboxy terminal fusions, in the order of approximately 1 to 10 residues. Examples of amino or carboxy terminal fusion proteins or peptides include the binding domain or activation domain of a transcriptional activator as used in the yeast two-hybrid system, phage coat proteins, (histidine) 6 tag, of glutathione S transferase, protein A, maltose binding protein, dihydrofolate reductase, labeling epitope 100, c-mic epitope, FLAG® epitope, lacZ, PCM (calmodulin binding peptide), HA epitope, epitope of protein C and epitope of VSV. Homologs in the form of "deletion variants" of a protein are characterized by the removal of one or more amino acids from a protein. Amino acid variants of a protein can be easily made using synthetic peptide techniques well known in the art, such as synthesis of solid phase peptides and the like, or by manipulations of recombinant DNA. Methods for manipulating DNA sequences to produce substitution, insertion or deletion variants of a protein are well known in the art. For example, techniques for creating substitution mutations at predetermined sites on DNA are well known to those skilled in the art and include mutagenesis of M13, mutagenesis of the T7 gene in vitro (USB, Cleveland, OH), site-directed mutagenesis of QuickChange. (Stratagene, San Diego, CA), site-directed mutagenesis mediated by PCR or other site-directed mutagenesis protocols.

The EFTu polypeptide or homologue thereof can be a derivative. "Derivatives" include peptides, oligopeptides, polypeptides, proteins and enzymes which may comprise substitutions, deletions or additions of amino acid residues present in nature and not present in nature compared to the amino acid sequence of a form present in the nature of the protein, for example, as presented in SEQ ID NO: 2. "Derivatives" of a protein encompass peptides, oligopeptides, polypeptides, proteins and enzymes that may comprise residues of amino acids present in nature, altered, glycosylated, acylated or not present in nature, compared to the amino acid sequence of a form present in the nature of the polypeptide. A derivative may also comprise one or more substituents that are not amino acids compared to the amino acid sequence from which, for example, a reporter molecule or another ligand is derived, covalently or non-covalently linked to the amino acid sequence, such as the molecule reporter that binds to facilitate its detection, and amino acid residues not present in nature in relation to the amino acid sequence of a protein present in nature. The EFTu polypeptide or homologue thereof can be encoded by an alternative spliced variant of a nucleic acid / EFTu gene. The term "alternative spliced variant" as used herein encompasses variants of a nucleic acid sequence in which selected introns and / or exons have been deleted, replaced or added. Said variants will be ones in which the biological activity of the protein is retained, which can be achieved by selectively retaining functional segments of the protein. These splice variants can be found in nature or can be axes by man. Methods for creating such splice variants are well known in the art. Preferred splice variants are splice variants of the nucleic acid represented by SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, SEQ ID NO: 7, SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 15, SEQ ID NO: 17, SEQ ID NO: 19 and SEQ ID NO: 21, but any polypeptide that meets the criteria of reasons comprising the motifs: (i) following GTP binding domains in any order GXXXXGK and DXXG and NKXD and S / L / K / QA / GL / V / F, where X is any amino acid; and (ii) the EFTu domain ALMANPAIKR or a domain having 50% identity to it and / or KD / G EE S / A. The homolog can also be encoded by an allelic variant of a nucleic acid encoding EFTu or a homologue thereof, preferably an allelic variant of the nucleic acid represented by SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, SEQ ID NO: 7, SEQ ID NO: 9, SEQ ID NO: 11, SEC ID NO: 13, SEQ ID NO: 15, SEQ ID NO: 17, SEQ ID NO: 19 and SEQ ID NO: 21. Useful in the methods of the invention are allelic variants encoding polypeptides comprising: (i) following GTP binding domains in any order GXXXXGK and DXXG and NKXD and S / L / K / QA / GL / V / F, where X is any amino acid, and (ii) the EFTu domain ALMANPAIKR or a domain that has 50% identity to the same and / or KD / G EE S / A. Allelic variants exist in nature and within the methods of the present invention the use of these natural alleles is covered. These include Single Nucleotide Polymorphisms (SNPs) as well as Small Insertion / Suppression Polymorphisms (INDELs). The size of INDEL is usually less than 100 bp. The SNP and INDEL of the largest set of sequence variants in polymorphic strains present in the nature of most organisms. In accordance with a preferred aspect of the present invention, improved or increased expression of the EFTu nucleic acid or variant thereof is provided. Methods for obtaining improved or increased expression of genes or gene products are well documented in the art and include, for example, overexpression driven by appropriate promoters, the use of transcription enhancers or translational enhancers. The isolated nucleic acids that serve as promoter or enhancer elements can be introduced in an appropriate position (usually upstream) of a non-heterologous form of a polynucleotide so as to regulate the expression of a EFTu nucleic acid or variant thereof. For example, endogenous promoters can be altered in vivo by mutation, deletion, and / or substitution (see, Kmiec, U.S. Patent No. 5,565,350; Zarling et al., PCT / US93 / 036868), or promoters isolated in a plant cell in the proper orientation and distance of a gene of the present invention so as to control gene expression. If expression of polypeptides is desired, it is generally convenient to include a polyadenylation region at the 3 'end of a polynucleotide coding region. The polyadenylation region can be derived from the natural gene, from a variety of different plant genes, or from T-DNA. The sequence of the 3 'end that will be added may be derived from, for example, nopaline synthase or octapina synthase genes, or alternatively from another plant gene, or less preferably from any other eukaryotic gene. Methods for preferably increasing the activity of an EFTu polypeptide in a plastid are described above.

A sequence of introns can also be added that can be added to the untranslated region 51 or the coding sequence of the partial coding sequence to increase the amount of mature message that accumulates in the cytosol. The inclusion of an intron that can be divided into the transcription unit in expression constructs of plants and animals has been shown to increase gene expression in both mRNA and protein levels up to 1000-fold, Buchman and Berg, Mol. Cell biol. 8: 4395-4405 (1988); Callis et al., Genes Dev. 1: 1183-1200 (1987). Such improvement in introns of gene expression is usually greatest when placed near the 5 'end of the transcription unit. The use of maize introns, intron Adhl-Sl, 2, and 6, the intron Bronze-1, is known in the art. See generally, The Maize Handbook, Chapter 116, Freeling and Walbot, Eds. , Sringer, N. Y. (1994). The invention also provides constructs and genetic vectors to facilitate the introduction and / or expression of nucleotide sequences useful in the methods according to the invention. Therefore, a gene construct is provided which comprises: (i) An EFTu nucleic acid encoding a polypeptide comprising: (a) the following GTP binding domains in any order GXXXXGK and DXXG and NKXD and S / L / K / QA / GL / V / F, where X is any amino acid; and (b) the EFTu domain ALMANPAIKR or a domain that has 50% identity to it and / or K D / G EE S / A; and (ii) one or more control sequences capable of directing the expression of the nucleic acid sequence of (i); and optionally (iü) a transcription termination sequence. Constructs useful in the methods according to the present invention can be constructed using recombinant DNA technology well known to those skilled in the art. Gene constructs can be inserted into vectors, which may be commercially available, suitable for transformation into plant cells and suitable for the expression of the gene of interest in the transformed cells. The plants were transformed with a vector comprising the sequence of interest (i.e., an EFTu nucleic acid or homologue thereof). The sequence of interest is operably linked to one or more control sequences (at least one promoter). The terms "regulatory element", "control sequence" and "promoter" are all used interchangeably herein and should be considered in a broad context to refer to the regulatory nucleic acid sequences capable of effecting the expression of the sequences at the which are linked. The aforementioned terms encompass the transcriptional regulatory sequences derived from a classical eukaryotic genomic gene (including the TATA box that is required for the initiation of precise transcription, with or without a CCAAT box sequence) and the additional regulatory elements (ie, upstream activation sequences, enhancers and silencers) that alter gene expression in response to developmental and / or external stimuli, or in a tissue-specific manner. Also, within the term a transcriptional regulatory sequence of a classical prokaryotic gene is included, in which case it may include a sequence of -35 cells and / or transcriptional regulatory sequences of -10 cells. The term "regulatory element" also encompasses a synthetic fusion molecule or derivative that confers, activates or enhances the expression of a nucleic acid molecule in a cell, tissue or organ. The term "operably linked" as used herein, refers to a functional linkage between the promoter sequence and the gene of interest, so that the promoter sequence can initiate transcription of the gene of interest. Advantageously, any type of promoter can be used to boost the expression of a nucleic acid sequence, however, our studies have revealed that some promoters outperform others in the methods of the invention. Preferably, the promoter is a tissue-specific promoter, i.e., one which is layers of preferably initiating transcription in certain tissues, such as leaves, roots, seed tissue, etc., substantially to the exclusion of initiating transcription in another part of the plant, but while still allowing residual expression in other parts of a plant due to selection promoters. Studies have shown that the use of seed-specific promoters, more particularly embryo-specific and / or aileron-specific promoters, behaves better in the methods of the invention (ie, gives plants with better performance) than the constitutive promoters in the same methods. It is therefore preferred that the EFTu nucleic acid or variant thereof is operably linked to a seed-specific promoter. A seed-specific promoter is transcriptionally active predominantly in seed tissue, but not necessarily exclusively in seed tissue (in case of selection expression). Seed-specific promoters are well known in the art. Preferably, the seed-specific promoter is an embryo-specific and / or aleurone-specific promoter, more preferably an oleosin promoter (see for example, SEQ ID NO: 29 which represents the sequence of the rice oleosin promoter). It should be clarified that the applicability of the present invention is not restricted to the EFTu-like nucleic acid represented by SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, SEQ ID NO: 7, SEQ ID NO: 9 , SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 15, SEQ ID NO: 17, SEQ ID NO: 19 and SEQ ID NO: 21, nor is the applicability of the invention restricted to the expression of a EFTu nucleic acid when driven by an oleosin promoter. Optionally, one or more sequences of terminators can be used in the construction introduced in a plant. The term "terminator" encompasses a control sequence that is a DNA sequence at the end of a transcriptional unit that signals 3 'processing and polyadenylation of a primary transcript and transcription termination. Additional regulatory elements may include transcriptional as well as translational speakers. Those skilled in the art will be aware that the terminator and enhancer sequences may be suitable for use in the embodiment of the invention. Said sequences could be known or easily obtained to a person skilled in the art. The genetic constructs of the invention may further include a replication sequence origin, which is required for maintenance and / or replication in a specific cell type. An example is when a genetic construct is required to remain in a bacterial cell as an episomal genetic element (e.g., plasmid or cosmid molecule). Preferred origins of replication include, but are not limited to fl-ori and colEl. The genetic construct optionally comprises a selectable marker gene. As used herein, the term "selectable marker gene" includes any gene that confers a phenotype on a cell in which it is expressed to facilitate the identification and / or selection of cells that are transfected or transformed with a nucleic acid construct. of the invention. Suitable markers can be selected from markers that confer resistance to antibiotics or herbicides, which introduces a new metabolic trait that allows visual selection. Examples of selectable marker genes include genes that confer resistance to antibiotics (such as nptll that phosphorylate neomycin and kanamycin or hpt, hygromycin phosphorylation), to herbicides (eg, bar that provides resistance to Basta; aroA or gox that provides resistance against glyphosate), or genes that provide a metabolic trait (such as manA allows plants to use mannose as a single source of carbon). Visual marker genes result in color formation (e.g., β-glucuronidase, GUS), luminescence (such as luciferase) or fluorescence (Green Fluorescent Protein, GFR, and derivatives thereof). The present invention also encompasses plants or parts of plants obtainable by the methods according to the present invention. Therefore, the present invention provides plants or parts thereof that can be obtained by the method according to the present invention, said plants have introduced therein an EFTu nucleic acid or variant thereof (transgene). The invention also provides a method for the production of transgenic plants having improved developmental characteristics, comprising introduction and expression in a plant or parts of plants (including plant cell) of a EFTu nucleic acid nucleic acid or variant thereof. The product of the nucleic acid expression gene is directed to a plastid in a plant cell if it is not already in the plastid. More specifically, the present invention provides a method for the production of transgenic plants having improved growth characteristics, said method comprising: (i) introducing and / or expressing in an plant or part of a plant (including plant cell) an acid EFTu nucleic acid or variant thereof encoding a polypeptide comprising: (a) the following GTP binding domains in any order GXXXXGK and DXXG and NKXD and S / L / K / QA / GL / V / F, wherein X is any amino acid; and (b) the EFTu domain ALMANPAIKR or a domain that has 50% identity to it and / or K D / G EE S / A; and (ii) cultivating the plant cell under conditions that promote plant growth and development. The nucleic acid can be introduced directly into a plant cell or into the plant itself (including introduction into a tissue, organ or any other part of a plant). According to a preferred aspect of the present invention, the nucleic acid is preferably introduced into a plant by transformation. The term "transformation" as it is referred to herein encompasses the transfer of an exogenous polynucleotide in a host cell, with respect to the method used for transfer. The tissue of plants capable of subsequent clonal propagation, either by organogenesis or embryogenesis, can be transformed with a genetic construct of the present invention and a whole regenerated plant thereof. The particular tissue chosen will vary depending on the clonal propagation systems available for, and best suited for, the particular species that is being transformed. Illustrative tissue targets include leaf discs, pollen, embryos, cotyledons, hypocotyledons, megagametophytes, callus tissue, existing meristematic tissue (eg, apical meristem, axillary buds, and root meristems), and induced meristem tissue (eg. gr., cotyledon meristem and hypocotyledons meristem). The polynucleotide can be temporary or stably introduced into a host cell and can be maintained in a non-integrated manner, for example, as a plasmid. Alternatively, it can be integrated into the host genome. The resulting transformed plant cell can then be used to regenerate a transformed plant in a manner known to those skilled in the art. The transformation of plant species is now a merely routine technique. Advantageously, any of several transformation methods can be used to introduce the gene of interest into a suitable ancestral cell. Transformation methods include the use of liposomes, electroporation, chemicals that increase the absorption of free DNA, injection of DNA directly into the plant, particle bombardment, transformation using viruses or pollen and micro projection. The methods can be selected from the method of calcium / propylene glycol for protoplasts (Krens et al. (1982) Nature 296, 72-74; Negrutiu et al. (1987) Plant Mol. Biol. 8, 363-373); electroporation of protoplasts (Shillito et al. (1985) Bio / Technol 3, 1099-1102); microinjection in plant material (Crossway et al. (1986) Mol. Gen. Enet. 202, 179-185); infection by bombardment of particles coated with DNA or RNA (Klein et al. (1987) Nature 327, 70) with viruses (non-integrators) and the like. Transgenic rice plants expressing an HKT protein are preferably produced via Agrobacterium-mediated transformation using any of the well-known methods for rice transformation, such as those described in any of the following: published European patent application EP 1198985 Al, Aldemita and Hodges (Planta 199, 612-617, 1996); Chan et al. (Plant Mol. Biol. 22, 491-506, 1993), Hiei et al. (Plant J. 6, 271-282, 1994), the descriptions of which are hereby incorporated by reference as being shown in their entirety. In the case of corn transformation, the preferred method is as described in both Ishida et al (Nature Biotechnol., 14, 745-50, 1996) and Frame et al. (Plant Physiol., 129, 13-22, 2002), whose descriptions incorporated herein by reference in their entirety. Generally after transformation, plant cells or cell clusters are selected for the presence of one or more markers that are encoded by genes that can be expressed in plants co-transferred with the gene of interest, after which the material is regenerated. transformed into a complete plant. Following the transfer and regeneration of DNA, putatively transformed plants can be evaluated, for example, using Southern analysis, for the presence of the gene of interest, number of copies and / or genomic organization. Alternatively or additionally, the levels of expression of the newly introduced DNA can be monitored using Northern and / or Western analysis, both techniques being well known to those of ordinary skill in the art. The transformed transformed plants can be propagated by a variety of means, such as by clonal propagation or classical breeding techniques. For example, a first generation of transformed plant (or IT) can be independent to give homozygous second generation (or T2) transformants and the T2 plants are also propagated through classical breeding techniques. The transformed organisms generated can have a variety of forms. For example, they may be chimeras of transformed cells and untransformed cells, clonal transformants (e.g., all transformed cells containing the expression cassette); grafts of transformed and non-transformed tissues (eg, in plants, a transformed rhizome grafted to a non-transformed shoot). The present invention clearly extends to any plant or plant cell produced by any of the methods described herein and to all parts of plants and propagules thereof. The present invention further extends to encompass the progeny of a primary transfected primary cell, tissue, organ or whole transformed plant that has been produced by any of the methods mentioned above, the only requirement being that the progeny exhibit the same genotypic characteristics and / or phenotypic than those produced in the mother by the methods according to the invention. The invention also includes host cells that contain an isolated EFTu nucleic acid or variant thereof. The preferred host cells according to the invention are plant cells. The invention also extends to harvestable parts of a plant according to the invention, such as, but not limited to seeds, leaves, fruits, flowers, stems, rhizomes, tubers or bulbs. The invention further relates to products derived (preferably directly) from a harvestable part of said plant, such as dry pellets or powders, oil, fat and fatty acids, starch or proteins.

The present invention also encompasses the use of EFTu nucleic acids or variants thereof and the use of EFTu nucleic acid-like polypeptides or variant thereof, to increase yield, especially seed yield in plants grown under stress-free conditions. Seed yield is as defined above. The EFTu nucleic acids or variants thereof, or EFTu polypeptides or homologs thereof, may find use in reproduction programs in which a DNA marker is identified can be genetically linked to an EFTu gene or variant thereof. Nucleic acids / EFTu genes or variants thereof, or EFTu polypeptides or homologs thereof may be used to define a molecular marker. This DNA or protein marker can be used in breeding programs to select plants that have improved plant yield. The EFTu gene or variant thereof may, for example, be a nucleic acid as represented by one of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, SEQ ID NO: 7, SEQ ID NO. : 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 15, SEQ ID NO: 17, SEQ ID NO: 19 and SEQ ID NO: 21. Allelic variants of a nucleic acid / EFT gene they can also find use in book-assisted reproduction programs. Such breeding programs sometimes require the introduction of allelic variation by mutagenic treatment of the plants, using for example, mutagenesis of EMS; alternatively, the program can start with a collection of allelic variants of the "natural" origin, so-called, produced unintentionally. The identification of allelic variants takes place, for example, by PCR. This is followed by a selection step for the selection of higher allelic variants of the sequence in question and which results in improved growth characteristics in a plant. The selection is usually carried out by monitoring growth performance of plants containing allelic variants different from the sequence in question, for example, different allelic variants of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, SEC ID NO: 7, SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 15, SEQ ID NO: 17, SEQ ID NO: 19 and SEQ ID NO: 21. The performance of Growth can be monitored in a greenhouse or in the field. Optional additional steps include crossing plants, in which the allelic variant was identified with another plant. This could be used, for example, to form a combination of phenotypic characteristics of interest. A nucleic acid of EFTu nucleic acid or variant thereof can also be used as probes to genetically and physically map the genes of which they are a part, and as markers for traits linked to those genes. This information can be useful in the reproduction of plants in order to develop lines with desired phenotypes. Said use of EFTu nucleic acid nucleic acids or variants thereof requires only a nucleic acid sequence of at least 15 nucleotides in length. EFTu nucleic acid nucleic acids or variants thereof can be used as restriction fragment length polymorphism (PLFR) markers. Southern (Maniatis) analyzes of restriction-digested genomic DNA can be tested with EFTu nucleic acid nucleic acids or variants thereof. The resulting band-forming patterns can then be subjected to genetic analyzes using computer programs such as MapMarker (Lander et al. (1987) Genomics 1, 174-181) in order to construct a genetic map. In addition, the nucleic acids can be used to test Southern blots containing genomic DNA treated with restriction endonuclease from a group of individuals representing the parents and progeny of a defined genetic cross. Segregation of DNA polymorphisms are noted and used to calculate the position of the HKT nucleic acid or variant thereof in the genetic map previously obtained using this population (Botstein et al. (1989) Am. J. Hum. Gent. 32, 314-331).

The production and use of probes derived from plant genes for use in genetic mapping is described in Bematzky and Tanksley (1986) Plant Mol. Biol. Repórter 4, 37-41. Numerous publications describe genetic mapping of specific cDNA clones using the methodology described above or variations thereof. For example, populations of internal F2 crosses, populations of later crosses, populations randomly matched, isogenic lines nearby, and other groups of individuals can be used for mapping. Said methodologies are well known to experts in the field. Nucleic acid probes can also be used for physical mapping (ie, placement of sequences on physical maps, see Hoheisel et al., In: Nonmammlian Genomic Analysis: A Practical Guide, Academic Press 1996, pp. 319-346, and references cited at the moment). In another embodiment, nucleic acid probes can be used in direct fluorescence in situ hybridization (HISF) mapping (Trask (1991) Trends Genet, 7, 149-154). Although current methods of HISF mapping favor the use of large clones (many hundreds of kb, see Laan et al. (1995) Genome Res. 5, 13-20), improvements in sensitivity may allow the performance of HISF mapping using shorter probes.

A variety of methods based on nucleic acid amplification of genetic and physical mapping can be carried out using the nucleic acids. Examples include specific amplification for alleles) (Kzazian (1989) J. Lab. Clin. Med. 11, 95-96), fragment polymorphism amplified by PCR (CAPS, Sheffield et al., (1993) Genomics 16, 325-332 ), specific binding for alleles (Landegren et al., (1988) Science 241, 1077-1080), nucleotide extension reaction (Sokolov (1990) Nucleic Acid Res. 18, 3671), Radiation Hybrid apping (Walter et al. (1997). ) Nat. Genet 7, 22-28) and Happy Mapping (Dear and Cook (1989) Nucleic Acid Res. 17, 6795-6807). For these methods, the nucleic acid sequence is used to design and produce pairs of primers for use in the amplification reaction or primer extension reactions. The design of said initiators is well known to those skilled in the art. In methods employing PCR-based genetic mapping, it may be necessary to identify DNA sequence differences between the parents of the mapping cross in the region corresponding to the nucleic acid sequence present. However, it is generally not necessary for mapping methods. The performance of the methods according to the present invention results in plants having increased plant performance developed under stress conditions, as described above. This increased plant yield can also be combined with other economically advantageous characteristics, such as additional performance features, tolerance to various stresses, characteristics that modify various architectural aspects and / or biochemical and / or physiological aspects.

DESCRIPTION OF THE FIGURES The present invention will now be described with reference to the following figures in which: Fig. 1 shows the alignment of multiple CLÜSTAL W of various plant EFTu polypeptides. The EFTu motif is represented by an additional EFTu motif is represented by and a GTP binding motif is represented by Fig. 2 shows a binary vector for Oryza sativa expression of a working EFTu under the control of a promoter of oleosin. Fig. 3 details examples of sequences useful for carrying out the methods according to the present invention.

EXAMPLES The present invention will now be described with reference to the following examples, which by way of illustration are unique. DNA manipulation: unless otherwise stated, recombinant DNA techniques are performed according to normal protocols described in (Sambrook (2001) Molecular Cloning: a laboratory manual, 3rd Edition Cold Spring Harbor Laboratory Press, CSH , New York) or in Volumes 1 and 2 of Ausubel et al. (1994), Current Protocols in Molecular Biology, Current Protocols. Normal materials and methods for molecular work of plants are described in Plant Molecular Biology Labfase (1993) by R.D.D. Croy, published by BIOS Scientific Publications Ltd (Rü) and Blackwell Scientific Publications (Rü).

Example 1: Gene Cloning The gene encoding an EFTu protein was first identified as an expressed sequence tag of BY2 tobacco cells and was isolated as a partial sequence in a cDFA-AFLP experiment performed with cDNA made from a culture of BY2 cells of synchronized tobacco. { Nicotiniana tabacum L. cv. Bright Yellow-2). Based on this cDNA-AFLP experiment, BY2 tags that were modulated in their cell cycle were identified and selected for further cloning. The expressed sequence tags were used to screen a tobacco cDNA library and to isolate the full-length cDNA.

Synchronization of BY2 cells The cultured cell suspension of BY2 of tobacco. { Nicotiana tahacum: cv. Bright Yellow-2) was synchronized by blocking cells in the early S phase with aphidicolin in the following manner. A suspension of cultured cells of Nicotiana tabacum L. cv. Bright Yellow-2 were maintained as described (Nagata et al., Int. Rev. Cytol. 132, 1-30, 1992). For synchronization, a 7-day-old stationary culture was diluted 10 times in fresh culture medium supplemented with aphidicolin (Sigma-Aldrich, St. Louis, MO; 5 mg / 1), a DNA-Polymerase a) inhibition drug. After 24 hours, the cells were released from the block by several washes with fresh medium and summarized their cell cycle progression.

Extraction of AKN and cDNA synthesis Total RNA was prepared using LiCl precipitation (Sambrook et al., 2001) and poly (A +) RNA was extracted from 500 g of total RNA using Oligotex columns. (Quiagen, Hilden, Germany) according to the manufacturer's instructions. Starting from 1 poly (A +) RNA, cDNA from the first strand was synthesized by reverse transcription with a biotinylated oligo-dT25 primer (Genset, Paris, France) and Superscript II (Life Technologies, Gaithersburg, MD). Synthesis of the second strand was performed by strand displacement with Escherichia coli ligase (Life Tehcnologies), DNA polymerase I (USB, Cleveland, OH) and RNase-H (USB): AFLP analysis of cDNA Five hundred ng of double-stranded cDNA were used for AFLP analysis as described (Vos et al., Nucleic Acids Res. 23 (21) 4407-4414, 1995; Bachem et al., Plant J. 9 ( 5) 745-53, 1996) with modifications. The restriction enzymes used were BstYI and Msel (Biolabs) and the digestion was carried out in two separate steps. After the first restriction digestion with one of the enzymes, two fragments of the 3 'end were collected in Dyna beads (Dynal, Oslo, Norway) by means of their biotinylated tail, while the other fragments were washed. After digestion with the second enzyme, the released restriction fragments were collected and used as models in the subsequent AFLP steps. For preamplifications, an Msel primer without selective nucleotides was combined with a BstYI primer containing either a T or a C as the majority of 3 'nucleotides. The CPR conditions were as described (Vos et al., 1995). The obtained amplification mixtures were diluted 600 times and 5 μ? they were used for selective amplifications using a P33-labeled BstYI primer and Amplitaq-Gold polymerase (Roche Diagnostics, Brussels, Belgium). The amplification products were separated in 5% polyacrylamide gels using the Sequigel system (Biorad). The dried gels were exposed to Kodak Biopmax films as well as scanned on a Phospholmager (Amersham Pharmacia Biotech, Little Chalfont, UK).

Characterization of AFLP fragments The bands corresponding to differentially expressed transcripts, among which the transcript was corresponding to SEQ ID NO 1, were isolated from the gel and the eluted DNA was reamplified under the same conditions as for the selective amplification. The sequence information was obtained either by direct sequencing of the polymerase chain reaction product reamplified with the selective BstYI primer or after cloning of the fragments in pGEM-Teasy (Promega, Madison, WI) or by individual sequencing clones. The sequences obtained were compared against nucleotide and protein sequences present in the publicly available databases by alignments of BLAST sequences (Altschul et al., Nucleic Acids Res. 25 (17) 3389-3402, 1997). When available, tag sequences were replaced with longer ESEs or isolated cDNA sequences to increase the chance of finding significant homology. The physical cDNA clone corresponding to SEQ ID NO 1 was subsequently amplified from a cDNA commercial dome bank follows.

Gene Cloning A cDNA library with average inserts of 1,400 bp was made with poly (A +) isolated from BY2 tobacco cells or synchronized actively divided. These bank inserts were cloned into the pCMVSPORT6.0 vector, comprising a Gateway cassette attB (Life Technologies). From this bank, 46,000 clones were selected, arranged in 384 well microtitre plates, and subsequent duplicate spots were formed on nylon filters. The disposed clones were screened using combinations of several hundred radioactively labeled tags as probes (among which was the label of BY2 corresponding to the sequence of SEQ ID NO: 1). Positive clones were isolated (between which the clone reacted with the corresponding BY2 tag for the sequence of SEQ ID NO 1), sequenced, aligned with the tag sequence. In cases where label hybridization failed, full-length cDNA corresponding to the tag was selected by PCR amplification as follows. The specific primers for Labels were designed using the primer program 3 (http://www.genome.wi.mit.edu/genome_software/ other / primer3.html) and used in combination with the common vector primer to amplify inserts of partial cDNAs. DNA combinations of 50,000, 100,000, 150,000 and 300,000 cDNA clones were used as models in PCR amplifications. The amplification products were isolated from agarose gels, cloned, sequenced and aligned with labels. Subsequently, the full-length aDNc corresponding to SEQ ID NO 1 was cloned from the pCM Sport 6.0 bench vector into a suitable plant expression vector via a Gateway LR reaction.

LR gate reaction to clone the gene into a plant expression vector pCMV Sport 6.0 was subsequently used in an LR reaction with a Gateway destination vector suitable for rice transformation. This vector contains as functional elements within the limits of DNA T a selectable marker of plants and a Gateway cassette intended for in vivo recombination of LR with the sequence of interest and cloned in the donor vector. Upstream of this gate cassette is the rice prolamin promoter for specific expression of seed of the gene. After the recombination step, the resulting expression vector (see Fig. 2) was transformed into strain LBA4404 of Agrobacterium and subsequently in plants of Example 3: Evaluation and Results Approximately 15 to 20 independent TO rice transformants were generated. The primary transformants were transferred from tissue culture chambers to a greenhouse for growth and harvested from IT seeds. 5 events, of which were retained from the progeny of TI, were segregated 3: 1 for the presence / absence of the transgenes. For each of these events, approximately 10 IT seedlings containing the transgene (heterozygous and homozygous) and in the same number, approximately 10 Ti seedlings lacking the transgene (nullizygotes), were selected by visual monitoring marker expression. In addition, 4 IT events were evaluated in the generation of T2 following the same evaluation procedure as for the generation of IT but with more individuals per event.

Statistical analysis: F-test A two-factor ANOVA (variant analysis) was used as a statistical model for the global evaluation of plant phenotypic characteristics. An F test was carried out on all the measured parameters of all the plants of all the events transformed with the gene of the present invention. The F test was carried out to review an effect of the gene on all transformation events and to verify a general effect of the gene, also known as the global gene effect. The threshold for significance for a global gene effect was established at a 5% probability level for the F test. A significant F test value indicates a gene effect, meaning that it is not only the presence or position of the gene that causes the differences in phenotypes. 3. 1 Parameter measurements related to seeds The mature primary panicles were harvested, packed in bags, marked with bar codes and then dried for three days in the oven at 37 ° C. The panicles were then threshed and all the seeds were collected and counted. The filled shells were separated from the empty ones using an air blowing device. The empty shells were discarded and the remaining fraction counted again. The full shells were weighed on an analytical balance. The total seed production was measured by weighing all the full husks harvested from a plant. The harvest index of the present invention was defined as a ratio of the total seed production and the area on the ground (mm2) multiplied by a factor of 106. 3. 2 Area on Earth The area on the ground was determined by counting the total number of pixels of the images of the parts of the plants on the ground discriminated from the bottom of the earth. This value was averaged for the images taken at the same time point from different angles and converted to a physical surface value expressed in square mm per calibration. The experiments show that the plant area on the measured earth correlates in this way with the biomass of the plant. The following table of results shows the p values of the F test for the Ti and Ti evaluations. The percentage of difference between the transgenics and the corresponding nullizygotes. For example, in the case of the number of seeds filled, 2 lines in the generation of IT gave a greater than 50% difference in the number of full seeds obtained from transgenic plants compared to the number of full seeds obtained from corresponding nullizygotes; the p-value of the F test of these two lines was less than 0.12. In general, 5 lines were evaluated for the number of filled seeds giving a percentage difference of 19% for the number of seeds filled with transgenic plants compared to the number of seeds filled with corresponding nullizygotes; and a p-value of the F test of these 5 lines gave a value of 0.05. Similarly, in the generation of T2, 1 line gave a difference of 23% for the number of full seeds obtained from transgenic plants compared to the number of full seeds obtained from corresponding nullizygotes; the p-value of the F test for this line was 0.08. In general, in generation T2, 3 lines were evaluated for the number of seeds filled giving a percentage difference between the number of seeds filled with transgenic plants compared to the number of seeds filled with corresponding nullizygotes of 11%; a p-value of the F test for these 3 lines gave a value of 0.08.

Claims (27)

1. - Method for increasing the yield in plants grown under stress-free conditions, comprising preferably increasing activity in a plastid of a translation elongation factor (EFTu) or a homologue thereof comprising: (i) the following GTP binding domains in any order GXXXXGK and DCXXG NKXD and S / L / K / QA / GL / V / F, where X is any amino acid; and (ii) EFTu domain ALMANPAIKR or a domain that has a growing identity preference order of at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95% thereof and / or KD / GS / A, and optionally selecting plants that have increased yield relative to corresponding wild type plants developed under comparable conditions.

2. The method according to claim 1, wherein the increased activity is carried out by introducing a genetic modification preferably at the site of a gene encoding said EFTu polypeptide or a homologue thereof.

3. The method according to claim 2, wherein the genetic modification is carried out by one of: site-directed mutagenesis, directed evolution, homologous recombination, TILLING, and T-DNA activation.

4. - The method for increasing the yield of plants in plants grown under stress-free conditions, comprising (i) introducing and expressing in a plant or part of a plant a nucleic acid of

EFTu or variant thereof that encodes an EFTU polypeptide comprising: (a) the following GTP binding domains in any order GXXXXGK and DXXG and NKXD and S / L / K / QA / GL / V / F, wherein X is any amino acid; and (b) the EFTu domain ALMANPAIKR or a domain that has 50% identity to it and / or K D / G EE S / A; and (ii) directing the polypeptide to a plastid in the plant cell unless the nucleic acid or variant thereof is a plastidic gene. 5. - The method according to claim 4, wherein the variant is a portion of an EFTu nucleic acid or a sequence capable of hybridizing an EFTu nucleic acid, said portion or hybridization sequence encoding a polypeptide comprising: i) the following GTP binding domains in any order GXXXXGK and DXXG and NKXD and S / L / K / QA / GL / V / F, where X is any amino acid; and (ii) the EFTu domain ALMANPAIKR or a domain that has 50% identity to it and / or K D / G EE S / A.

6. - The method according to claim 4 or 5, wherein the EFTu nucleic acid or variant thereof is over-expressed in a plant.

7. - The method according to any of claims 4 to 6, wherein the EFTu nucleic acid or variant thereof is of plant origin, preferably of a dicotyledonous plant, preferably in addition to the Solanaceae family, more preferably of the genus Nicotinanae

8. The method according to any of claims 4 to 6, wherein said EFTu nucleic acid or variant thereof is operably linked to a seed-specific promoter, preferably to a specific promoter for embryos and / specific for ailerons.

9. The method according to claim 8, wherein the promoter is an oleosin promoter.

10. - The method according to any of claims 1 to 9, wherein the increased yield is increased seed yield relative to the corresponding wild-type plants.

11. - The method according to any of claims 1 to 10, wherein said increased yield is biomass of plants on the ground increased.

12. The method according to any of claims 1 to 11, wherein the increased yield gives increased growth rate in relation to the corresponding wild-type plants.

13. The method according to claim 10, wherein the increased seed growth is selected from any one or more of (i) increased seed biomass.; (ii) increased number of seeds (full); (iii) increased seed size; (iv) increased seed volume; (v) increased harvest index; and (vi) bulb seed weight increased one thousand times (PSM).

14. - Plants that can be obtained by a method according to any of claims 1 to 13.

15. - Construction comprising: (i) An EFTu nucleic acid encoding a polypeptide comprising: (a) the following domains of GTP binding in any order GXXXXGK and DXXG and NKXD and S / L / K / QA / GL / V / F, where X is any amino acid; and (b) the EFTu domain ALMANPAIKR or a domain that has 50% identity to it and / or K D / G EE S / A; and (ii) a. or more control sequences capable of directing the expression of the nucleic acid sequence of (i); and optionally (iii) a transcription termination sequence.

16. - Construction according to claim 15, wherein the seed-specific promoter is a specific promoter for embryos and / or specific ailerons.

17. - Construction according to claim 15 or 16, wherein the promoter is an oleosin promoter.

18. - Plant transformed with a construction according to any of claims 15 to 17.

19. - Method for the production of a transgenic plant that has increased yield under conditions without stress in relation to the yield of corresponding wild type plants developed under comparable conditions, said method comprises: (i) introducing and expressing in a plant or part of a plant an EFTu nucleic acid or variant thereof encoding an EFTU polypeptide comprising: (a) the following GTP binding domains in any order GXXXXGK and DXXG and NKXD and S / L / K / QA / GL / V / F, where X is any amino acid; and (b) the EFTu domain ALMANPAIKR or a domain that has 50% identity to it and / or K D / G EE S / A; and (ii) cultivate the plant or part of the plant under conditions that promote the growth and development of plants.

20. - Transgenic plants grown under stress-free conditions and having increased yield, particularly increased yield, relative to wild type plants grown under comparable conditions, the increased yield resulting from an EFTu nucleic acid or variant thereof introduced and expressed in said plant, the EFTu nucleic acid or variant thereof encoding a polypeptide comprising: (a) the following GTP binding domains in any order GXXXXGK and DXXG and NKXD and S / L / K / QA / GL / V / F, where X is any amino acid; and (b) the EFTu domain AL ANPAIKR or a domain having 50% identity to it and / or KD / G EE S / A, said polypeptide is targeted to a plastid in a plant cell if it is not already in the cell. plastid

21. - The transgenic plant according to claim 14, 18 or 20, wherein the plant is a monocotyledonous plant, such as sugarcane or wherein the plant is a cereal, such as rice, corn, wheat, barley, millet, rye, oats or sorghum.

22. Harverable parts of a plant according to any of claims 14, 18, 20 or 21.

23. - harvestable parts according to claim 22, wherein the harvestable parts are seeds.

24. Products derived from a plant according to claim 21, or harvestable parts according to claim 22 or 23.

25. - Use of a nucleic acid / EFTu gene or variant thereof or use of a polypeptide of EFTu or its counterpart to increase plant yield, especially seed yield, in plants grown under stress-free conditions.

26. - Use according to claim 25, wherein the seed yield includes one or more of the following: increased number of seeds (filled), increased seed weight, increased harvested index and increased PSM.

27. - Use of a EFTu nucleic acid / gene or variant thereof or use of a EFTu-like polypeptide or homologue thereof as a molecular marker.