EP0975799A1 - Moyens pour l'identification de sequences nucleotidiques impliquees dans l'apomixie - Google Patents
Moyens pour l'identification de sequences nucleotidiques impliquees dans l'apomixieInfo
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- EP0975799A1 EP0975799A1 EP98909558A EP98909558A EP0975799A1 EP 0975799 A1 EP0975799 A1 EP 0975799A1 EP 98909558 A EP98909558 A EP 98909558A EP 98909558 A EP98909558 A EP 98909558A EP 0975799 A1 EP0975799 A1 EP 0975799A1
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- European Patent Office
- Prior art keywords
- apomictic
- plants
- corn
- apomixis
- sequence
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- C—CHEMISTRY; METALLURGY
- C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
- C12Q—MEASURING OR TESTING PROCESSES INVOLVING ENZYMES, NUCLEIC ACIDS OR MICROORGANISMS; COMPOSITIONS OR TEST PAPERS THEREFOR; PROCESSES OF PREPARING SUCH COMPOSITIONS; CONDITION-RESPONSIVE CONTROL IN MICROBIOLOGICAL OR ENZYMOLOGICAL PROCESSES
- C12Q1/00—Measuring or testing processes involving enzymes, nucleic acids or microorganisms; Compositions therefor; Processes of preparing such compositions
- C12Q1/68—Measuring or testing processes involving enzymes, nucleic acids or microorganisms; Compositions therefor; Processes of preparing such compositions involving nucleic acids
- C12Q1/6876—Nucleic acid products used in the analysis of nucleic acids, e.g. primers or probes
- C12Q1/6888—Nucleic acid products used in the analysis of nucleic acids, e.g. primers or probes for detection or identification of organisms
- C12Q1/689—Nucleic acid products used in the analysis of nucleic acids, e.g. primers or probes for detection or identification of organisms for bacteria
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- C—CHEMISTRY; METALLURGY
- C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
- C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
- C12N15/00—Mutation or genetic engineering; DNA or RNA concerning genetic engineering, vectors, e.g. plasmids, or their isolation, preparation or purification; Use of hosts therefor
- C12N15/09—Recombinant DNA-technology
- C12N15/63—Introduction of foreign genetic material using vectors; Vectors; Use of hosts therefor; Regulation of expression
- C12N15/79—Vectors or expression systems specially adapted for eukaryotic hosts
- C12N15/82—Vectors or expression systems specially adapted for eukaryotic hosts for plant cells, e.g. plant artificial chromosomes (PACs)
- C12N15/8241—Phenotypically and genetically modified plants via recombinant DNA technology
- C12N15/8261—Phenotypically and genetically modified plants via recombinant DNA technology with agronomic (input) traits, e.g. crop yield
- C12N15/8287—Phenotypically and genetically modified plants via recombinant DNA technology with agronomic (input) traits, e.g. crop yield for fertility modification, e.g. apomixis
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- C—CHEMISTRY; METALLURGY
- C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
- C12Q—MEASURING OR TESTING PROCESSES INVOLVING ENZYMES, NUCLEIC ACIDS OR MICROORGANISMS; COMPOSITIONS OR TEST PAPERS THEREFOR; PROCESSES OF PREPARING SUCH COMPOSITIONS; CONDITION-RESPONSIVE CONTROL IN MICROBIOLOGICAL OR ENZYMOLOGICAL PROCESSES
- C12Q2600/00—Oligonucleotides characterized by their use
- C12Q2600/13—Plant traits
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- C—CHEMISTRY; METALLURGY
- C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
- C12Q—MEASURING OR TESTING PROCESSES INVOLVING ENZYMES, NUCLEIC ACIDS OR MICROORGANISMS; COMPOSITIONS OR TEST PAPERS THEREFOR; PROCESSES OF PREPARING SUCH COMPOSITIONS; CONDITION-RESPONSIVE CONTROL IN MICROBIOLOGICAL OR ENZYMOLOGICAL PROCESSES
- C12Q2600/00—Oligonucleotides characterized by their use
- C12Q2600/156—Polymorphic or mutational markers
Definitions
- the invention relates to means for identifying, isolating and characterizing nucleotide sequences involved in apomixis. It relates more particularly to a process and tools making it possible to identify these sequences in the genome of apomictic plants, then to isolate and characterize them.
- apomixis In its modern sense, apomixis, or agamospermia, includes all of the phenomena of asexual reproduction by seed. Apomictic plants are found in nearly 300 species of angiosperms belonging to more than 35 families. The different forms of apomixis, which generally affect only female reproduction, are characterized by the absence of meiotic reduction, the absence of fertilization of the oosphere, and the parthenogenetic development of embryos. Apomixis therefore leads to the production of descendants genetically identical to their mother plant.
- apomixis The natural counterpart of apomixis is sexual reproduction, or amphimixis.
- sexual reproduction includes processes including both reductional meiosis and syngamy.
- Meiosis randomly distributes homologous chromosomes from parents between gametes. It also allows recombination between homologous chromosomes, via crossing-overs. Syngamy is the fusion of gametes. It allows to gather in an individual a particular combination of genetic information from both parents. Amphimixis therefore produces, by recombination of the parental genomes, genetically unique descendants.
- the first generation corresponds to the sporophyte.
- One or more sporophyte cells undergo meiosis, producing meiospores.
- the meiospores develop into gametophytes, which represent the gametophytic generation, at the origin of gametes.
- the fusion of gametes leads to the zygote, which represents the return to the sporophytic generation.
- the female gametophyte (the embryonic sac) develops in a very differentiated multicellular structure of the sporophyte, the ovum.
- the archesporial cell goes through two successive stages: megasporogenesis (formation of a megaspore, or meiospore, reduced from an archesporial cell) and megagametogenesis (formation of female gametophyte from a megaspore) to produce a multicellular gametophyte that contains a single gamete, the oosphere.
- This type of development (Polygonum type) concerns almost 80% of angiosperms.
- the different forms of apomixis correspond to a series of variations on this theme.
- the origin of the embryo allows a first subdivision between two fundamental forms of apomixis.
- Gametophytic apomixis In adventitious embryos, the embryos differentiate directly from somatic cells of the nucella or the seed coat of the ovum. There is therefore no alternation of the sporophytic and gametophytic generations.
- Gametophytic apomixis is characterized by the formation of an unreduced female gametophyte, and the parthenogenetic development of the embryo from the oosphere. In the rest of the text, any reference to apomixis will refer to gametophytic apomixis. There are two main types of gametophytic apomixis, which differ in the origin of the female gametophyte. In aposporic forms, the unreduced embryo sac is derived from a somatic cell in the ovum, usually the nucella.
- the male gametophyte (the grain of pollen) contains two sperm.
- Both the embryo and the endosperm are sexual.
- the embryo develops without fertilization, but the albumen remains sexed.
- pseudogamy, or pseudogamous apomixis when fertilization of the central cell is necessary for the development of the endosperm, and autonomous apomixis when both the embryo and the endosperm develop without fertilization.
- apomixis therefore corresponds well to asexual reproduction by seed. It results from a sum of clearly identifiable components: apomeiosis, or formation of a sac embryonic without meiotic reduction, and parthenogenesis, or formation of an embryo without fertilization of the oosphere. Apomeiosis and parthenogenesis ensure the alternation of the sporophytic and gametophytic generations, but without alternation of the nuclear phases: sporophyte and gametophyte retain the same level of ploidy.
- apomixis is actually a mixed mode of reproduction, combining amphimixis and asexual reproduction.
- apomixis is generally an optional phenomenon: it appears in the offspring of apomictic plants of "off-type" individuals, that is to say genetically different from their mother plant.
- off-types can appear if one or both conditions are not met, depending on the achievement or failure of meiosis and fertilization, the classes of possible descendants in an optional apomictic plant are as follows :
- the first term designates the state of the gametophyte, reduced (n) or unreduced (2n). translates the presence or absence of fertilization of the oosphere.
- the category “2n + n” leads to a genetic accumulation, and the category w n + 0 "to the haploidization of the mother plant.
- the respective proportions of these different categories vary from one species to another, and even from one plant to another within a given species.
- the references to apomixis relate to both the optional apomictic forms and the obligatory apomictic forms producing exclusively 2n + 0 type progenies.
- Apomixis arouses great interest in view of its potential for plant improvement.
- the use of apomixis in the main cultivated plants would represent a simple way of fixing heterosis. This is potentially a revolution in the manipulation of reproductive systems.
- Arabidopsis thaliana is the most used model ((9), (10) and
- orthologous genes means genes which have diverged from a common gene, or from genes paralogs, along with the species that carry them.
- the targeted genes have the same functions with respect to apomixis.
- the genus Tripsacum belongs to the Andropogonee tribe. It is the only known relative of the genus Zea on the American continent (4) and (11) have carried out the most complete study of the modes of reproduction in Tripsacum. This work made it possible to specify the following points: - all polyploid accessions reproduce by diplosporic apomixis,
- the non-reduction in apomictic forms is mainly of Antennaria type, with rare occurrence of Taraxacum type, - the embryonic bags in diplosporic forms come directly from megasporocytes by 3 successive mitoses, the failure of meiosis in diplosporic forms is associated with the absence of callose deposits around megasporocytes,
- the invention therefore aims to provide a method for identifying in a grass, and more particularly in a corn, a gene orthologous to a gene involved in apomixis. It also aims to provide a method of isolating the sequence of this gene.
- the invention further relates to the use of this sequence to isolate the corresponding orthologous gene sequences in apomictic plants and the applications of these sequences in transgenesis.
- the method according to the invention for identifying in a grass, and more particularly in a corn, a nucleotide sequence orthologous of sequence responsible for all or part of the apomictic development in an apomictic form, is characterized in that one maps in the grass genome, more specifically that of a corn, mutations having a phenotypic expression close to or similar to that observed in an apomictic form, to identify those of these mutations which appear orthologs of genes involved in apomixis.
- a related phenotype is identified here based on four characteristics of the diplosporic forms, which can be observed either independently or in conjunction: (a) mutations are specific to megasporogenesis and do not affect male reproductive function, (b) they lead to the formation of unreduced gametes from an archesporial cell, (c) they are characterized by the absence of callose deposits around the mother cells of the megaspore, (d) the control points which act normally during the formation of the embryo sac appear inactive, and the embryo sacs are normally formed despite the failure of a stage during megasporogenesis.
- the reference in the method defined above to the identification of nucleotide sequences includes the identification of loci or genes in an embodiment of the method of the invention, or mapping in the genome of the grass, more especially that of a corn, meiotic mutations to identify those which appear orthologs of genes involved in apomixis.
- the invention relates in particular to a method of identification in a grass, more particularly in a corn, of a sequence of genes orthologous to that of the gene controlling apomeiosis in apomictic forms, characterized in that the expression is studied phenotypic and that localize the position of different meiotic mutations in the grass genome, more specifically of a corn, using molecular markers capable of locating the loci responsible for apomeiosis in said apomictic form.
- the localized mutations according to the invention are cloned and sequenced.
- the inventors have in particular demonstrated that the genes involved in the expression of apomixis in Tripsacum have one or more orthologs in the corn genome.
- the use according to the invention of the same set of markers in maize and Tripsacum has made it possible to identify candidate genes having both (1) the same genomic location as the genes controlling diplosporia, in the sense that they are located in the same chromosomal region of a segment which, in maize, is homeologous to that controlling diplosporia in Tripsacum, and (2) a related phenotype, depending on criteria previously mentioned.
- the location concerns the elongate and afd loci in the corn genome.
- the method of the invention is further characterized in that it includes labeling using transposons of localized meiotic mutations.
- the invention relates in particular to labeling using transposons of the elongate locus.
- transposons whose sequence is known makes it possible to create a mutation for a gene of which only the phenotypic expression is known.
- the insertion of the transposon into the gene that one seeks to isolate is often characterized by the loss of its function. In the case of recessive alleles, it is frequently characterized by the appearance of the recessive phenotype in heterozygous plants.
- Particularly interesting transposons include the transposable elements of the Mutator type, or Ac / Ds.
- the localized mutations are cloned and sequenced.
- a mutated gene can be isolated by locating the site of insertion of the transposon, the different loci in which transposons have been inserted being cloned by the conventional techniques of Mendelian analysis and molecular biology (12) and (13), and sequences if desired.
- the site is first characterized phenotypically for the expression of the ell allele. It is then located by genetic mapping, and its position compared to that of the loci controlling diplosporia in Tripsacum. The loci are then labeled via transposons, isolated and then sequenced.
- the invention also relates to the use of at least part of a sequence as defined above to identify, then isolate, the sequence of orthologous genes in apomictic forms.
- the invention relates, as such, to the isolated nucleotide sequences. These sequences are characterized in that they are orthologs of sequences responsible for all or part of the development in an apomictic form.
- the invention also includes the sequences homologous, in terms of function, to those identified above.
- the invention relates in particular to a nucleotide sequence of this type corresponding to the mutated elongate gene.
- Nucleic acids containing one or more sequences as defined above associated with regulatory sequences necessary for expression in plant material also form part of the invention.
- the invention also includes the cloning and expression vectors comprising such nucleic acids as well as the cellular hosts containing these vectors, for example Agrobacterium tumefaciens.
- the invention also relates to the use of such sequences, where appropriate in conjunction with other alleles characteristic of apomictic forms, for transforming the genome of plant material, plant cells, plants, at various stages of development, and seeds. , in order to give them an apomictic development.
- Said alleles correspond to genes other than the orthologous genes targeted by the invention.
- the invention relates in particular to a process for the production of apomictic plants, characterized in that a sequence of the mutated elongate gene as defined above is used.
- This transformed plant material falls within the scope of the invention and is characterized in that it contains in its genome at least the part of said sequence involved in apomictic development, if necessary in conjunction with other alleles characteristic of apomictic forms.
- the cells, plants and seeds concerned belong to the family of grasses. This is particularly corn.
- the transformation of plant material, cells, plants and seeds is obtained by operating advantageously according to conventional transgenic techniques. For example, for obtaining transgenic corn plants.
- the genetic transformation of corn whatever the method used (electroporation; Agrobacterium, microfibers, particle cannon), generally requires the use of undifferentiated cells in rapid divisions which have retained the ability to regenerate whole plants.
- This type of cell makes up the embryogenic friable callus (called type II) of corn.
- type II embryogenic friable callus
- These calluses are obtained from immature embryos of genotype Hl II or (A188 x B73) according to the method and on the media described by Armstrong (1994). The calluses thus obtained are multiplied and maintained by successive subcultures every fortnight on the initiation medium.
- Seedlings are then regenerated from these calluses by modifying the hormonal and osmotic balance of the cells according to the method described by Vain et al. (1989). These plants are then acclimatized in the greenhouse where they can be crossed or self-fertilized.
- the preceding paragraph describes obtaining and regenerating the cell lines necessary for transformation; a method of genetic transformation leading to the stable integration of the modified genes into the plant genome is described here.
- This method is based on the use of a particle gun; the target cells are fragments of calluses described in paragraph 1. These fragments with an area of 10 to 20 mm 2 were placed, 4 h before bombardment, at the rate of 16 fragments per dish in the center of a petri dish containing a culture medium identical to the initiation medium, supplemented with 0.2 M mannitol + 0.2 M sorbitol.
- the plasmids carrying the genes to be introduced are purified on a Qiagen column, following the manufacturer's instructions. They are then precipitated on tungsten particles (M10) following the protocol described by Klein et al,
- Suitable selective agents generally consist of active compounds of certain herbicides (Basta ®, Roundup ®,) or certain antibiotics (Hygromycin, Kanamycin ).
- Calls are obtained after 3 months or sometimes earlier, calluses whose growth is not inhibited by the selection agent, usually and mainly composed of cells resulting from the division of a cell having integrated into its genetic heritage one or more copies of the selection gene.
- the frequency of obtaining such calluses is approximately 0.8 cal per bombarded box.
- calluses are identified, individualized, amplified and then cultivated so as to regenerate seedlings. In order to avoid interference with non- transformed all these operations are carried out on culture media containing the selective agent. The plants thus regenerated are acclimatized and then cultivated in a greenhouse where they can be crossed or self-fertilized.
- the invention thus provides means for disposing of a population of apomictic plants and having active transposable elements.
- hybridization probes produced from said sequences as well as the primers which can be used in PCR techniques, therefore form part of the invention.
- Such probes and primers correspond in particular to those developed from the elongate sequence.
- hybridization or PCR techniques are advantageously carried out according to conventional methods.
- the invention also relates to a method for identifying and isolating a gene responsible for diplosporia in apomictic Tripsacum, characterized in that at least part of the sequence of the elongate locus is used.
- the method of the invention is further characterized in that the sequence isolated from apomictic Tripsacum is used for the functional analysis of the relationship between this sequence and the expression of apomixis.
- a mutagenesis method is used, as illustrated in the examples, making it possible to confirm the relationship between the sequence isolated in apomictic Tripsacum from the sequence of the elongate gene and the phenotypic expression of apomixis.
- the relationship between said sequence and the expression of apomeiosis is confirmed in particular.
- FIGS. 1 to 5 respectively represent: - Figure 1, the genetic mapping of the chromosome segment controlling diplosporia in an apomictic tetraploid Tripsacum, and the comparison with sexed diploid plants in Tripsacum and maize, - Figure 2, the construction of a mapping population for the mutation ell, (elongate),
- FIG. 3 the construction of a mutagenesis population for labeling the elongate locus
- the population includes 175 FI plants, of which 56 have been used for mapping.
- the mapping population includes 232 FI maize plants - Tripsacum.
- the apomictic plant was used as a male.
- the allele must be simplex in the tetraploid, that is to say differentiable from the 3 others.
- FIG. 1 represents the genetic mapping of the chromosomal segment controlling apomeiosis, and the comparison with the diploid sexual plants in Tripsacum and maize.
- "Apo" corresponds to the locus responsible for apomeiosis.
- the position of umc71 on chromosome 6 in maize is indicated approximately, the allele on chromosome 6 having been removed from the latest versions of the UMC card.
- the probes detecting alleles linked to the chromosomal segment controlling diplosporia in Tripsacum all detect alleles belonging to the same linkage group on the corn map. It is the long arm of chromosome 6. Some of them also detect alleles in other regions of the genome, in particular chromosomes 3 and 8.
- the locations on the corn map of the various probes linked to apomeiosis are given in the following table:
- meiosis mutants There are very many meiosis mutants in corn.
- the phenotypic criteria retained in the choice of the candidate genes were as follows: (1) the presence of clearly differentiated archesporial cells (2) the total absence of induction of meiosis in these cells, or the failure thereof at an early stage (3) the capacity to produce a functional gametophyte independently of the failure of meiosis, (4) the absence or at least a very marked drop in callose deposits around the megaspore mother cell.
- potential candidates that is to say having all or some of the characteristics mentioned above, those whose position in the corn genome was unknown or imprecise were mapped using as reference loci those detected by the probes used for the mapping of apomeiosis in Tripsacum.
- chromosome 8 The precise location of the elongate locus was unknown until the invention. However, it was known to belong to the long arm of chromosome 8 in corn. It was therefore not located directly on the corn chromosome arm identified by Leblanc et al. as homeologist of the one controlling apomeiosis. Located on chromosome 8, however, it potentially belongs to a segment which happens to be duplicated between the distal part of the long arm of chromosome 6 and certain parts of chromosome 8 (15).
- Figure 2 describes the construction of a mapping population for the ell mutation
- Ell / ell were backcrossed on three ell / ell homozygous plants. For each family, 50 plant plants were put in the field, self-fertilized, and evaluated for their phenotype. Ell / ell seeds are expected to be normal, with ell / ell seeds showing a malformed albumen. In order to confirm the elongate phenotypes, ten to twenty embryos inside the seeds showing a defective albumen were removed, and analyzed by flow cytometry using the protocol proposed by Galbraiht et al (20). The ell mutation was obtained from the Maize Genetic Stock Center, Urbana, Illinois, in the form of seeds from the self-fertilization of plants homozygous for the ell allele in an otherwise undetermined genetic background.
- the homozygous wild phenotype line, 23, was used for the population construction. Link detection and estimation of recombination rates were obtained using Mapmaker 2.0 software, for machintosh. - Comparison of the phenotypic expression of apomeiotic and elo ⁇ grate plants
- the phenotypic expression of the elongate mutation in archesporial cells of homozygous ell / ell plants was analyzed by cytoembryology techniques previously described by Leblanc et al. (11). Immature inflorescences were collected on four types of material: (1) sexed diploid Tripsacum, (2) apomictic tetraploid Tripsacum, accessions described in Leblanc et al (11), (3) a line of homozygous corn Ell / Ell de wild phenotype (23), and (4) a homozygous ell / ell line.
- Transposon labeling consists in using transposons whose sequence is known in order to create a mutation for a gene of which only the phenotypic expression is known.
- the insertion of the transposon into the gene that one seeks to isolate is often characterized by the loss of its function. In the case of recessive alleles, it is frequently characterized by the appearance of the recessive phenotype in heterozygous plants.
- the mutated gene can then itself be cloned by locating the site of insertion of the transposon.
- the mutated gene can then be isolated by locating the transposon insertion site, the different loci where transposons were inserted being cloned by conventional Mendelian analysis and molecular biology techniques. The following experiments were carried out with the Mutator system (21).
- the population used for labeling the elongate locus using transposons is shown diagrammatically in FIG. 3 (f: frequency of appearance; [EL] and [el]: dominant and recessive phenotypes; El *: marked allele. plants homozygous for the recessive mutation are crossed on plants homozygous for the wild allele, Ell. In the population of gametes produced by the parent EL1 / Ell, one or more mutations are found at the elongate locus. When the insertion leads to the loss of the function of this allele, we then find some FI plants of genotype ell / Ell, but phenotype ell. The gene is then marked.
- Figure 4 allows the comparison of the development of archesporial cells in these different types of materials (A: megaspore mother cell in 23, corn of genotype Ell / Ell; B: megaspore mother cell in corn homozygous ell / ell ; C: megaspore mother cell in a sexed diploid Tripsacum; D: megaspore mother cell in an apomictic tetraploid Tripsacum).
- A megaspore mother cell in 23, corn of genotype Ell / Ell
- B megaspore mother cell in corn homozygous ell / ell
- C megaspore mother cell in a sexed diploid Tripsacum
- D megaspore mother cell in an apomictic tetraploid Tripsacum
- the developmental stages observed have been identified and synchronized between the different forms observed, based on the size and morphology of the external integuments of the ovum (11).
- a population of 12,500 FI plants produced according to Figure 3 were put in the field at the CIMMYT experimental station in Tlatizapan, Mexico.
- the 12,500 plants were fertilized by a corn hybrid devoid of active Mutator (hybrid CML135 * CML 62).
- the ears of 12500 were observed at maturity in order to detect those expressing the elongrate mutation although heterozygous at this locus.
- the corresponding embryos were analyzed by flow cytometry. Two plants identified as TTE1-5 and TTE1-7 were identified as having deficient endosperm associated with a triploid embryo.
- Example 3 obtaining and using a mutagenesis population making it possible to confirm the relationship between the candidate allele and the phenotype expression of all or part of the apomictic development
- the general diagram and the materials used are presented in Figure 5.
- the lines containing Mutator elements were obtained from M. Freeling, University of California at Berkeley.
- the BC2-28 dihaploid plants used here are those previously described by Leblanc et al (6). These are apomictic plants, with a haploid genome from each of the two parents of corn and Tripsacum origin. We have used these plants to introduce Mutator elements into apomictic material.
- a population of a thousand apomictic BC2-28 plants was first formed, from a single apomictic dihaploid plant, and by selecting from its progeny plants of type 2n + 0. We thus create a thousand copies of the same apomictic polyhaploid genotype. These thousand plants were crossed by Mutator stocks. In the offspring obtained, we selected for non-type plants 2n + n, that is to say having incorporated a genome from the Mutator stocks. These stocks have around 200 copies of the different types of Mutator s. We therefore hope to recover an average of 100 copies from apomictic plants. The selection of BC2-28 plants and apomictic BC3-38 off-types was made on a simple morphological criterion.
- Dihaploids indeed have a very recognizable phenotype, and very different from that which results from the accumulation of an additional corn genome (6).
- BC2-28 x Mutators seeds
- the whole was put in the field on the CIMMYT experimental station in Tlaltizapan, Morelos state, during the summer of 1996.
- the 2n + n off-types were selected one month after germination.
- Around 7,500 2n + n plants were obtained, i.e. almost 20% of off-types.
- This population was crossed by a corn hybrid (CML135 * CML62) devoid of active Mutator elements, producing a population about 150,000 seeds, representing the reverse genetics population.
- This population represents an ideal material for analyzing the effect of a given sequence on the expression of apomixis.
- the Tripsacum alleles responsible for the expression of this characteristic are here in simplex condition (a single copy in the genome). It is therefore sufficient to verify the allele-function relationship to control the phenotypic effect of the insertion of a transposon in this sequence. If the mutation induces a loss of function, then the sequence-function relationship has been established with certainty. Since the sequences of both the transposons and the gene studied are known, it is possible to identify the plants mutated for this allele by standard PCR techniques.
- Rhoades M. M.
- E. Dempsey 1966 Induction of chromosome doubling at meiosis by the elongate gene in maize. Genetics 54: 505-522.
- Galbraith D. W., K. R. Harkins, J. M.
Abstract
Description
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Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
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FR9701821A FR2759708B1 (fr) | 1997-02-17 | 1997-02-17 | Moyens pour identifier, isoler et caracteriser des sequences nucleotidiques impliquees dans l'apomixie |
FR9701821 | 1997-02-17 | ||
PCT/FR1998/000308 WO1998036090A1 (fr) | 1997-02-17 | 1998-02-17 | Moyens pour l'identification de sequences nucleotidiques impliquees dans l'apomixie |
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EP0975799A1 true EP0975799A1 (fr) | 2000-02-02 |
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EP98909558A Withdrawn EP0975799A1 (fr) | 1997-02-17 | 1998-02-17 | Moyens pour l'identification de sequences nucleotidiques impliquees dans l'apomixie |
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EP (1) | EP0975799A1 (fr) |
CN (1) | CN1248296A (fr) |
AU (1) | AU6405498A (fr) |
CA (1) | CA2282085A1 (fr) |
DE (1) | DE975799T1 (fr) |
ES (1) | ES2146561T1 (fr) |
FR (1) | FR2759708B1 (fr) |
WO (1) | WO1998036090A1 (fr) |
Families Citing this family (7)
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CA2389055A1 (fr) * | 1999-10-29 | 2001-05-10 | John G. Carman | Procedes servant a stabiliser et a controler l'apomixie |
EP1409514A4 (fr) | 2001-06-22 | 2005-02-02 | Ceres Inc | Polypeptides d'histone acetyltransferase chimeriques |
US7476777B2 (en) | 2002-09-17 | 2009-01-13 | Ceres, Inc. | Biological containment system |
US8878002B2 (en) | 2005-12-09 | 2014-11-04 | Council Of Scientific And Industrial Research | Nucleic acids and methods for producing seeds with a full diploid complement of the maternal genome in the embryo |
FR2952276A1 (fr) * | 2009-11-09 | 2011-05-13 | Inst Rech Developpement Ird | Induction de l'apomixie chez les plantes cultivees a reproduction sexuee et utilisation pour la reproduction de plantes totalement ou partiellement apomictiques |
EP2530160A1 (fr) | 2011-05-30 | 2012-12-05 | Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung Gatersleben (IPK) | Moyens et procédés pour induire l'apomixie chez les plantes |
JP6978152B2 (ja) | 2015-09-04 | 2021-12-08 | キージーン ナムローゼ フェンノートシャップ | 複相胞子生殖遺伝子 |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5710367A (en) * | 1995-09-22 | 1998-01-20 | The United States Of America As Represented By The Secretary Of Agriculture | Apomictic maize |
US5811636A (en) * | 1995-09-22 | 1998-09-22 | The United States Of America As Represented By The Secretary Of Agriculture | Apomixis for producing true-breeding plant progenies |
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1997
- 1997-02-17 FR FR9701821A patent/FR2759708B1/fr not_active Expired - Fee Related
-
1998
- 1998-02-17 WO PCT/FR1998/000308 patent/WO1998036090A1/fr not_active Application Discontinuation
- 1998-02-17 CA CA002282085A patent/CA2282085A1/fr not_active Abandoned
- 1998-02-17 AU AU64054/98A patent/AU6405498A/en not_active Abandoned
- 1998-02-17 EP EP98909558A patent/EP0975799A1/fr not_active Withdrawn
- 1998-02-17 ES ES98909558T patent/ES2146561T1/es active Pending
- 1998-02-17 DE DE0975799T patent/DE975799T1/de active Pending
- 1998-02-17 CN CN98802588A patent/CN1248296A/zh active Pending
Non-Patent Citations (1)
Title |
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See references of WO9836090A1 * |
Also Published As
Publication number | Publication date |
---|---|
CA2282085A1 (fr) | 1998-08-20 |
AU6405498A (en) | 1998-09-08 |
FR2759708A1 (fr) | 1998-08-21 |
CN1248296A (zh) | 2000-03-22 |
WO1998036090A1 (fr) | 1998-08-20 |
DE975799T1 (de) | 2000-08-31 |
ES2146561T1 (es) | 2000-08-16 |
FR2759708B1 (fr) | 1999-08-27 |
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