Dominant Gene Suppression Transgenes and Methods of Using Same

Abstract

Pairs of plants are provided in which complementing constructs result in suppression of a parental phenotype in the progeny. Methods to generate and maintain such plants, and methods of use of said plants, are provided, including use of parental plants to produce sterile plants for hybrid seed production. Also provided are regulatory elements for pollen-preferred expression of linked polynucleotides. Also provided are methods for identifying gene function, methods for testing allelic variants, and methods for repressing transmission of transgenes.

1 . A breeding pair of plants comprising four polynucleotides, wherein 
 (a) the first plant of said pair comprises (i) a first polynucleotide which encodes a gene product and is operably linked to a promoter A, and (ii) a second polynucleotide which encodes a pIR polynucleotide targeting a promoter sequence B, wherein promoter B is not present in said first plant; and    (b) The second plant of said pair comprises (iii) a third polynucleotide which encodes a gene product and is operably linked to said promoter B, and (ii) a fourth polynucleotide which encodes a pIR polynucleotide targeting said promoter A, wherein promoter A is not present in said second plant.    
     
     
         2 . The breeding pair of plants of  claim 1 , wherein one or more of said four polynucleotides is exogenous.  
     
     
         3 . The breeding pair of plants of  claim 1 , wherein said gene products affect the same phenotypic trait.  
     
     
         4 . The breeding pair of plants of  claim 3 , wherein said trait is male fertility.  
     
     
         5 . The breeding pair of plants of  claim 3 , wherein said trait is female fertility.  
     
     
         6 . The breeding pair of plants of  claim 1 , wherein 
 (a) said first polynucleotide is selected from the group consisting of polynucleotides encoding maize MS45, maize BS7, maize 5126, and the corresponding orthologs from  Arabidopsis  and rice;    (b) said second promoter is selected from the group consisting of rice MS45, rice BS7, rice 5126,  Arabidopsis  BS7,  Arabidopsis  5126, and  Arabidopsis  MS45 promoters;    (c) said third polynucleotide is selected from the group consisting of polynucleotides encoding maize MS45, maize BS7, maize 5126, and the corresponding orthologs from  Arabidopsis  and rice;    (d) said first promoter is selected from the group consisting of rice MS45, rice BS7, rice 5126,  Arabidopsis  BS7,  Arabidopsis  5126, and  Arabidopsis  MS45 promoters.    
     
     
         7 . A method of generating plants lacking a particular phenotype from parents exhibiting said phenotype, comprising crossing the breeding pair of plants of  claim 3 .  
     
     
         8 . A cell of a plant of  claim 1 .  
     
     
         9 . Seed or progeny of a plant of  claim 1 .  
     
     
         10 . A method for selectively expressing a first polynucleotide of interest in progeny of a plant, comprising: 
 (a) transforming said plant with a first construct comprising said polynucleotide operably linked to a first exogenous promoter;    (b) transforming a second plant with a second construct comprising a promoter inverted repeat (pIR) targeting said first exogenous promoter;    (c) crossing said first and second plants; and    (d) selecting progeny comprising said first and second constructs, where expression is not desired; and    (e) selecting progeny comprising said first construct but not said second construct, where expression is desired.    
     
     
         11 . The method of  claim 10  wherein said second construct comprises, or is co-transformed with, a selectable marker gene.  
     
     
         12 . The method of  claim 10  wherein said first plant further comprises a third construct comprising a pIR targeting a second exogenous promoter, and said second plant further comprises a fourth construct comprising a second polynucleotide of interest operably linked to said second exogenous promoter.  
     
     
         13 . The method of  claim 12  wherein said first and second polynucleotides of interest affect the same phenotypic trait.  
     
     
         14 . The method of  claim 13  wherein said trait is male fertility.  
     
     
         15 . The method of  claim 13  wherein said trait is female fertility.  
     
     
         16 . The method of  claim 13  wherein said first and second polynucleotides encode the same gene product.  
     
     
         17 . A male-sterile plant produced by the method of  claim 14 .  
     
     
         18 . A method of evaluating the function of an allelic variant of an endogenous gene in a plant or plant cell, comprising: 
 (a) silencing said endogenous gene using a promoter inverted repeat construct targeted to said endogenous promoter; and    (b) expressing said allelic variant operably linked to a non-target promoter.    
     
     
         19 . The method of  claim 17  comprising the plant of  claim 18  as a first plant and further comprising a second plant, wherein said second plant comprises a promoter inverted repeat targeting the promoter operably linked to said allelic variant in said first plant.