Herbicide-resistant rice plants, polynucleotides encoding herbicide resistant acetohydroxyacid synthase large subunit proteins, and methods of use

Abstract

Herbicide-resistant rice plants, isolated polynucleotides that encode herbicide resistant and wild-type acetohydroxyacid synthase large subunit 1 (AHASL1) polypeptides, and the amino acid sequences of these polypeptides, are described. Expression cassettes and transformation vectors comprising the polynucleotides of the invention, as well as plants and host cells transformed with the polynucleotides, are described. Methods of using the polynucleotides to enhance the resistance of plants to imidazolinone herbicides, and methods for controlling weeds in the vicinity of herbicide-resistant plants are also described.

1 - 83 . (canceled) 
     
     
         84 . A isolated, recombinant, mutagenized, or synthetic rice AHASL1 nucleic acid molecule, or a complement thereof, that encodes a variant rice AHASL1 polypeptide comprising an aspartate or valine substitution at amino acid position 179 or equivalent position relative to the amino acid sequence as shown by SEQ ID NO:2, wherein expression of the variant rice AHASL1 polypeptide in a plant confers upon the plant tolerance to an AHAS-inhibiting herbicide as compared to a non-transformed variety of said plant. 
     
     
         85 . The rice AHASL1 nucleic acid molecule of  claim 84 , wherein the nucleic acid molecule comprises a nucleotide sequence encoding a polypeptide having the amino acid sequence as shown by SEQ ID NO:2. 
     
     
         86 . The rice AHASL1 nucleic acid molecule of  claim 84 , wherein the nucleic acid molecule comprises a nucleotide sequence as shown by SEQ ID NO:1. 
     
     
         87 . A isolated rice AHAS polypeptide encoded by the nucleic acid molecule of  claim 84 . 
     
     
         88 . A transformed plant comprising a polynucleotide construct comprising an isolated, recombinant, mutagenized, or synthetic rice AHASL1 nucleic acid molecule, or a complement thereof, that encodes a variant rice AHASL1 polypeptide comprising an aspartate or valine substitution at amino acid position 179 or equivalent position relative to the amino acid sequence as shown by SEQ ID NO:2, wherein expression of the variant rice AHASL1 polypeptide in the plant confers upon the plant tolerance to an AHAS-inhibiting herbicide as compared to a non-transformed variety of said plant, said nucleic acid molecule operably linked to a promoter that drives expression in said plant whereby the plant exhibits increased tolerance to an AHAS-inhibiting herbicide as compared to the non-transformed variety of said plant. 
     
     
         89 . The plant of  claim 88 , wherein the plant is a dicot or monocot. 
     
     
         90 . A seed of the plant of  claim 88 , wherein the seed comprises the construct. 
     
     
         91 . The seed of  claim 90 , wherein the seed is treated with an AHAS-inhibiting herbicide. 
     
     
         92 . The seed of  claim 91 , wherein the AHAS-inhibiting herbicide is an imidazolinone herbicide. 
     
     
         93 . The seed of  claim 92 , wherein the imidazolinone herbicide is selected from the group consisting of: 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-nicotinic acid, 2-(4-isopropyl)-4-methyl-5-oxo-2-imidazolin-2-yl)-3-quinolinecarboxylic acid, 5-ethyl-2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-nicotinic acid, 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-5-(methoxymethyl)-nicotinic acid, 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-5-methylnicotinic acid, and a mixture of methyl 6-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-m-toluate and methyl 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-p-toluate. 
     
     
         94 . The seed of  claim 91 , wherein the AHAS-inhibiting herbicide is a sulfonylurea herbicide. 
     
     
         95 . The seed of  claim 94 , wherein the sulfonylurea herbicide is selected from the group consisting of: is selected from the group consisting of: chlorsulfuron, metsulfuron methyl, sulfometuron methyl, chlorimuron ethyl, thifensulfuron methyl, tribenuron methyl, bensulfuron methyl, nicosulfuron, ethametsulfuron methyl, rimsulfuron, triflusulfuron methyl, triasulfuron, primisulfuron methyl, cinosulfuron, amidosulfuron, flazasulfuron, imazosulfuron, pyrazosulfuron ethyl, halosulfuron, and mixtures thereof. 
     
     
         96 . A plant part or cell of the plant of  claim 88 , wherein the part or cell comprises the construct. 
     
     
         97 . A method for controlling weeds in a field, said method comprising:
 (a) growing, in a field, a rice plant according to  claim 88 ; and   (b) contacting said plant and weeds in the field with an effective amount of an AHAS-inhibiting herbicide, thereby controlling the weeds.   
     
     
         98 . The method of  claim 97 , wherein the AHAS-inhibiting herbicide is selected from the group consisting of: 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-nicotinic acid, 2-(4-isopropyl)-4-methyl-5-oxo-2-imidazolin-2-yl)-3-quinolinecarboxylic acid, 5-ethyl-2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-nicotinic acid, 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-5-(methoxymethyl)-nicotinic acid, 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-5-methylnicotinic acid, and a mixture of methyl 6-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-m-toluate and methyl 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-p-toluate. 
     
     
         99 . A method for producing a plant having tolerance to an imidazolinone herbicide, the method comprising:
 (a) transforming a plant cell with the nucleic acid molecule of  claim 84 ; and   (b) generating from the plant cell a plant having increased tolerance to an imidazolinone herbicide as compared to a non-transformed variety of said plant.   
     
     
         100 . A plant produced according to the method of  claim 99 . 
     
     
         101 . A seed of the plant of  claim 100 , wherein the seed comprises the nucleic acid molecule. 
     
     
         102 . The seed of  claim 101 , wherein the seed is treated with an AHAS-inhibiting herbicide. 
     
     
         103 . A method for selecting for a transformed plant cell, the method comprising:
 (a) transforming a plant cell with a plant transformation vector;   (b) exposing said transformed plant cell to at least one herbicide at a concentration that inhibits the growth of an untransformed plant cell; and   (c) identifying said transformed plant cell by its ability to grow in the presence of said herbicide;   
       wherein said plant transformation vector comprises the nucleic acid molecule according to  claim 84 .