Methods and compositions for combinations of mutations associated with herbicide resistance/tolerance in rice

Abstract

Rice is described that is tolerant/resistant to herbicides, for example, ACCase inhibitors, and HPPD inhibitors, or both. For ACCase inhibitors, 2 different chromosome regions act synergistically in providing resistance/tolerance to the same herbicide class. Use of the herbicide resistant/tolerant rice for weed control and methods of producing tolerant/resistant rice are also disclosed.

1 . A method to protect a rice crop in a field, the method comprising:
 a. obtaining a rice crop in the field wherein the rice is resistant to dosages of ACCase inhibitors at levels that cause more injury to plants without a homozygous mutation in a gene encoding a substitution of amino acids G2096S in an ACCase enzyme than to plants with the homozygous mutation; and   b. contacting the field with at least one of the ACCase inhibitors at levels to which the rice is resistant.   
     
     
         2 . The method of  claim 1 , wherein the ACCase inhibitors herbicides are selected from the group consisting of aryloxyphenoxy propionate, fluazifop, propaquizafop and quizalofop. 
     
     
         3 . The method of  claim 1 , wherein the inhibitors are administered at a stage selected from the 2-leaf and 4-leaf stage of rice development. 
     
     
         4 . The method of  claim 1  wherein the dosage level is two times that recommended for the field and the rice crop by the manufacturer of the ACCase inhibitors. 
     
     
         5 . A method of producing rice tolerant to ACCase inhibitors at dosage levels significantly higher than those tolerated by rice without a genetic region conferring tolerance, the method comprising:
 a. obtaining the genetic region of tolerant rice wherein the region includes the mutated codon AGC, or its synonymous codons, encoding amino acid position 2096 of the ACCase protein, resulting in a substitution of serine for glycine in the expressed enzyme; and   b. introducing the genetic region into rice to replace the genetic region encoding the amino acid at position 2096.   
     
     
         6 . The method of producing GGC rice tolerant to ACCase inhibitors of  claim 5 , wherein introducing the genetic region is by transformation with any association of promoters, terminators, selectable markers, or other domains of the ACCase coding gene. 
     
     
         7 . A method for producing a rice seed, the method comprising crossing the plant of  claim 11  with a rice plant of a different genetic background, not including a substitution G2096S in the ACCase enzyme, and harvesting the resultant hybrid rice seed for use in breeding ACCase inhibitor/tolerant rice. 
     
     
         8 . An herbicide resistant rice plant from a seed produced by the method of  claim 7 . 
     
     
         9 . A method to protect a rice crop in a field from weeds that are sensitive to ACCase enzyme inhibitors, the method comprising:
 a. planting the rice crop in a field, wherein the rice crop is tolerant to dosages of ACCase inhibitors higher than are tolerated by the weeds and by rice without an ACCase enzyme with the amino acid substitution G2096S encoded by genes in the homozygous state; and   b. applying at least one ACCase inhibitor at dosages causing 10% or less injury in the tolerant rice.   
     
     
         10 . The method of  claim 9  wherein the ACCase inhibitors are applied at a stage of rice development selected from the group consisting of a 2 leaf and 4 leaf stage. 
     
     
         11 . A rice plant and its progeny comprising in their genome, a gene in homozygous form encoding a substitution G2096 in the ACCase enzyme, wherein the rice plant exhibits increased tolerance to ACCase inhibitors compared to a rice plant with only a single copy of the gene. 
     
     
         12 . A method for protecting a rice crop in a field, the method comprising:
 a. obtaining rice in the field wherein the rice is resistant to an ACCase inhibiting herbicide associated with a mutation, and wherein the rice is derived from ATCC Accession No. PTA-12933 through breeding, tissue culture, or transformation; and   b. applying the ACCase inhibiting herbicide to the field.   
     
     
         13 . The method of  claim 12  wherein the ACCase inhibiting herbicide is a FOP herbicide. 
     
     
         14 . The method of  claim 12  wherein the mutation associated with resistance is GGC to AGC and encodes a substitution in the ACCase enzyme from glycine to serine at position 2096. 
     
     
         15 . An ACCase inhibitor resistant rice plant comprising a DNA sequence as in SEQ ID NO:1 comprising a plastidic carboxylase transferase domain of a mutated ACCase coding gene which confers resistance to an ACCase herbicide selected from the group consisting of quizalofop, clodinafop-propargyl, haloxyfop-methyl, and combinations thereof. 
     
     
         16 . The rice plant of  claim 15  wherein the mutation is homozygous. 
     
     
         17 . (canceled)