Plants producing 2n gametes or apomeiotic gametes

Abstract

The invention relates to plants wherein the protein OSD1, involved in the transition from meiosis I to meiosis II is inactive. These plants produce Second Division Restitution (SDR) 2n gametes. The invention further relates to plants wherein the inactivation of OSD1 is combined with the inactivation of a gene involved in meiotic recombination in plants, and of a gene involved in the monopolar orientation of the kinetochores during meiosis. These plants produce apomeiotic gametes. These plants are useful in plant breeding.

1 . A method for obtaining a plant producing Second Division Restitution 2n gametes, wherein said method comprises the inhibition in said plant of a protein hereinafter designated as OSD1 protein, wherein said protein has at least 20° A) sequence identity, or at least 29% sequence similarity with the AtOSD1 protein of SEQ ID NO: 1, or with the OsOSD1 protein of SEQ ID NO: 35. 
     
     
         2 . A method according to  claim 1 , wherein inhibition of the OSD1 protein is obtained by mutagenesis of the OSD1 gene or of its promoter, and the mutants having partially or totally lost the OSD1 protein activity are selected. 
     
     
         3 . A method according to  claim 1 , wherein the inhibition of the OSD1 protein is obtained by expressing in said plant a silencing RNA targeting the gene encoding said protein. 
     
     
         4 . A method for obtaining a plant producing apomeiotic gametes, wherein said method comprises the inhibition in said plant of the following proteins:
 a) an OSD1 protein as defined in  claim 1 ;   b) a protein involved in initiation of meiotic recombination in plants, said protein being selected among:
 i) a protein hereinafter designated as SPO11-1 protein, wherein said protein has at least 40% sequence identity, or at least 60% sequence similarity with the SPO11-1 protein of SEQ ID NO: 2; 
 ii) a protein hereinafter designated as SPO11-2 protein, wherein said protein has at least 40% sequence identity, or at least 60% sequence similarity with the SPO11-2 protein of SEQ ID NO: 3; 
 iii) a protein hereinafter designated as PRD1 protein, wherein said protein has at least 25% sequence identity, or at least 35% sequence similarity with the prd1 protein of SEQ ID NO: 4; or 
 iv) a protein hereinafter designated as PAIR1 protein, wherein said protein has at least 30% sequence identity, or at least 40% sequence similarity with the PAIR1 protein of SEQ ID NO: 5; 
   c) a protein hereinafter designated as Rec8 protein, wherein said protein has at least 40% sequence identity, or at least 45% sequence similarity with the Rec8 protein of SEQ ID NO: 6.   
     
     
         5 . A method according to  claim 4 , wherein inhibition of at least one of the OSD1, SPO11-1, SPO11-2, PRD1, PAIR1, or Rec8 proteins is obtained by mutagenesis of the gene encoding said protein of or of its promoter, and the mutants having partially or totally lost the activity of said protein are selected. 
     
     
         6 . A method according to  claim 4 , wherein inhibition of at least one of the OSD1, SPO11-1, SPO11-2, PRD1, PAIR1, or Rec8 proteins is obtained by expressing in said plant a silencing RNA targeting the gene encoding said protein. 
     
     
         7 . An expression cassette comprising:
 a promoter functional in a plant cell;   at least one DNA construct selected among:   a) one or more DNA construct(s) of 200 to 1000 bp, each comprising a fragment of a cDNA of a target gene selected among OSD1, SPO11-1, SPO11-2, PRD1, PAIR1, and REC8, or of its complementary, or having at least 95% identity with said fragment, said DNA sequence(s) being placed under transcriptional control of said promoter.   b) one or more hairpin DNA construct(s) capable, when transcribed, of forming a hairpin RNA targeting a gene selected among OSD1, SPO11-1, SPO11-2, PRD1, PAIR1, and REC8; or   c) one or more DNA construct(s) capable, when transcribed, of forming an amiRNA targeting a gene selected among OSD1, SPO11-1, SPO11-2, PRD1, PAIR1, and REC8;   said DNA construct(s) being placed under transcriptional control of said promoter.   
     
     
         8 . An expression cassette of  claim 7  comprising a DNA construct targeting the OSD1 gene. 
     
     
         9 . An expression cassette of  claim 7 , comprising: a DNA construct targeting the OSD1 gene, a DNA construct targeting a gene selected among SPO11-1, SPO11-2, PRD1, and PAIR1, or a DNA construct targeting REC8. 
     
     
         10 . A recombinant vector comprising an expression cassette of  claim 7 . 
     
     
         11 . A plant producing Second Division Restitution 2n gametes, which is a transgenic plant containing a transgene comprising an expression cassette of  claim 8 . 
     
     
         12 . A plant producing apomeiotic gametes, obtainable by the method of  claim 4 . 
     
     
         13 . A plant producing apomeiotic gametes, which is a transgenic plant containing a transgene comprising an expression cassette of  claim 9 . 
     
     
         14 . A method for producing Second Division Restitution 2n gametes, wherein said method comprises cultivating a plant obtainable by a method of  claim 1 , and recovering the gametes produced by said plant. 
     
     
         15 . A method for producing apomeiotic gametes, wherein said method comprises cultivating a plant obtainable by a method of  claim 4 , and recovering the gametes produced by said plant. 
     
     
         16 . A recombinant vector comprising an expression cassette of  claim 8 . 
     
     
         17 . A recombinant vector comprising an expression cassette of  claim 9 .