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 methods for maintaining a homozygous recessive condition and for repressing transmission of transgenes.

What is claimed is: 
     
         1 . A method of suppressing a phenotype in progeny of a parental pair of plants, wherein
 (a) said phenotype is expressed in each of said parental plants;   (b) the genome of each parental plant is manipulated so as to inactivate a gene affecting the phenotype of interest; and   (c) the gene inactivated in the first parent encodes a different gene product than the gene inactivated in the second parent.   
     
     
         2 . The method of  claim 1  wherein said phenotype is fertility. 
     
     
         3 . The method of  claim 2  wherein said phenotype is male fertility. 
     
     
         4 . The method of  claim 3  wherein said inactivated genes are BS7 and SB200. 
     
     
         5 . The method of  claim 2  wherein said phenotype is female fertility. 
     
     
         6 . The method of  claim 1  wherein said inactivated genes encode gene products of a single pathway. 
     
     
         7 . The method of  claim 1  wherein said inactivated genes encode gene products of convergent pathways. 
     
     
         8 . The method of  claim 1  wherein, in at least one parent, said gene inactivation is accomplished by expression of an exogenous nucleic acid molecule encoding a hairpin ribonucleic acid molecule (hpRNA). 
     
     
         9 . The method of  claim 8  wherein said molecule encoding a hpRNA is operably linked to a constitutive promoter, a tissue-preferred promoter, or an inducible promoter. 
     
     
         10 . The method of  claim 9  wherein said promoter preferentially drives expression in male reproductive tissue. 
     
     
         11 . The method of  claim 10  wherein said promoter is an MS45 gene promoter, a 5126 gene promoter, a BS7 gene promoter, an SB200 gene promoter, a PG47 gene promoter, or a TA29 gene promoter. 
     
     
         12 . A breeding pair of plants, wherein
 (a) the pair exhibit a common phenotype as to a particular trait;   (b) each of the pair comprises an inactivated gene in a pathway affecting the phenotype; and   (c) the gene inactivated in the first plant encodes a different gene product than the gene inactivated in the second plant.   
     
     
         13 . The plants of  claim 12  wherein said phenotype is male fertility. 
     
     
         14 . The plants of  claim 13  wherein said inactivated genes are BS7 and SB200. 
     
     
         15 . The plants of  claim 12  wherein said phenotype is female fertility. 
     
     
         16 . The plants of  claim 12  wherein said inactivated genes encode gene products of a single pathway. 
     
     
         17 . The plants of  claim 12  wherein said inactivated genes encode gene products of convergent pathways. 
     
     
         18 . The plants of  claim 12  wherein, in at least one parent, said gene inactivation is accomplished by expression of an exogenous nucleic acid molecule encoding a hairpin ribonucleic acid molecule (hpRNA). 
     
     
         19 . The plants of  claim 18  wherein said molecule encoding a hpRNA is operably linked to a constitutive promoter, a tissue-preferred promoter, or an inducible promoter. 
     
     
         20 . The plants of  claim 19  wherein said tissue-preferred promoter preferentially drives expression in male reproductive tissue. 
     
     
         21 . The plants of  claim 20  wherein said promoter is an MS45 gene promoter, a 5126 gene promoter, a BS7 gene promoter, an SB200 gene promoter, a PG47 gene promoter, or a TA29 gene promoter. 
     
     
         22 . A cell of a plant of  claim 12 . 
     
     
         23 . Seed or progeny of the plants of  claim 12 . 
     
     
         24 . A method of maintaining the homozygous recessive condition of a first plant when crossing with a second plant, comprising
 (a) providing a first plant with a homozygous recessive genotype for male sterility;   (b) providing a maintainer plant by introducing into a second plant a restoring gene construct comprising
 (i) a first nucleotide sequence that, if introduced into the first plant, would restore male fertility, said first nucleotide sequence being in a hemizygous condition; and 
 (ii) a second nucleotide sequence, operably linked to the first nucleotide sequence, which inhibits the formation, function, or dispersal of male gametes of the maintainer plant, wherein said second nucleotide sequence encodes beta-amylase or a debranching enzyme; 
   (c) growing the maintainer plant such that all viable pollen produced contains the recessive allele and does not contain said restoring gene construct; and   (d) pollinating the first plant with the maintainer plant to produce progeny which maintain the homozygous recessive condition of the first plant.   
     
     
         25 . The method of  claim 24 , wherein said first nucleotide sequence is MS45. 
     
     
         26 . The method of  claim 24 , wherein the second nucleotide sequence is operably linked to a promoter preferentially directing expression in the male gametes. 
     
     
         27 . The maintainer plant of  claim 24 . 
     
     
         28 . The maintainer plant of  claim 24 , further comprising a third nucleotide sequence operably linked to the first nucleotide sequence and encoding a marker product capable of being used for selection of progeny comprising the restoring gene construct. 
     
     
         29 . A method of propagating the maintainer plant of  claim 28 , comprising self-pollinating said maintainer plant and selecting progeny based on presence of the selectable marker product. 
     
     
         30 . A method of preventing transmission of a transgene of interest to the gametes of a transgenic organism, comprising linking said transgene to a construct comprising a first promoter driving a nucleotide sequence encoding a product that inhibits the formation, function, or dispersal of gametes, wherein the gamete-inhibiting gene product is beta-amylase or a debranching enzyme. 
     
     
         31 . The method of  claim 30  wherein said first promoter preferentially drives expression in male gametes.