Plants having increased tolerance to herbicides
The present invention refers to a method for controlling undesired vegetation at a plant cultivation site, the method comprising the steps of providing, at said site, a plant that comprises at least one nucleic acid comprising a nucleotide sequence encoding a wild-type or a mutated protoporphyrinogen oxidase (PPO) which is resistant or tolerant to a PPO-inhibiting herbicide by applying to said site an effective amount of said herbicide. The invention further refers to plants comprising wild-type or mutated PPO enzymes, and methods of obtaining such plants.
1 . An isolated nucleic acid encoding a mutated protoporphyrinogen oxidase (mut-PPO) polypeptide, wherein the encoded mut-PPO polypeptide is a variant having an amino acid sequence with at least 75% identity to SEQ ID NO: and comprising an amino acid substitution at a position corresponding to position Leu397 of SEQ ID NO: 2 and an amino acid substitution at a position corresponding to position Phe420 of SEQ ID NO: 2, wherein the amino acid at a position corresponding to position Leu397 of SEQ ID NO:2 is substituted with aspartate, glutamate, or glutamine, and wherein the amino acid corresponding to position Phe420 of SEQ ID NO:2 is substituted with valine or methionine.
2 . A plant or plant cell comprising the nucleic acid encoding the mut-PPO polypeptide of claim 1 , wherein expression of the nucleic acid in the plant cell results in increased tolerance to a PPO inhibiting herbicide as compared to a wild type of the plant or plant cell.
3 . A seed produced by the plant of claim 2 , wherein the seed is true breeding for the increased resistance to a PPO inhibiting herbicide as compared to a wild type of the seed, and wherein the seed comprises the nucleic acid encoding the mut-PPO polypeptide.
4 . The isolated nucleic acid of claim 1 , wherein the encoded mut-PPO polypeptide is a variant having an amino acid sequence with at least 85 % identity to SEQ ID NO:42 and comprising an amino acid substitution at a position corresponding to position Leu397 of SEQ ID NO: 2 and an amino acid substitution at a position corresponding to position Phe420 of SEQ ID NO: 2, wherein the amino acid at a position corresponding to position Leu397 of SEQ ID NO:2 is substituted with aspartate, glutamate, or glutamine, and wherein the amino acid corresponding to position Phe420 of SEQ ID NO:2 is substituted with valine or methionine.
5 . The isolated nucleic acid of claim 1 , wherein the encoded mut-PPO polypeptide is a variant having an amino acid sequence with at least 90% identity to SEQ ID NO:42 and comprising an amino acid substitution at a position corresponding to position Leu397 of SEQ ID NO: 2 and an amino acid substitution at a position corresponding to position Phe420 of SEQ ID NO: 2, wherein the amino acid at a position corresponding to position Leu397 of SEQ ID NO:2 is substituted with aspartate, glutamate, or glutamine, and wherein the amino acid corresponding to position Phe420 of SEQ ID NO:2 is substituted with valine or methionine.
6 . The isolated nucleic acid of claim 1 , wherein the encoded mut-PPO polypeptide is a variant having an amino acid sequence with at least 95% identity to SEQ ID NO:42 and comprising an amino acid substitution at a position corresponding to position Leu397 of SEQ ID NO: 2 and an amino acid substitution at a position corresponding to position Phe420 of SEQ ID NO: 2, wherein the amino acid at a position corresponding to position Leu397 of SEQ ID NO:2 is substituted with aspartate, glutamate, or glutamine, and wherein the amino acid corresponding to position Phe420 of SEQ ID NO:2 is substituted with valine or methionine.
7 . The isolated nucleic acid of claim 1 , wherein the encoded mut-PPO polypeptide is a variant having an amino acid sequence with at least 98% identity to SEQ ID NO:42 and comprising an amino acid substitution at a position corresponding to position Leu397 of SEQ ID NO: 2 and an amino acid substitution at a position corresponding to position Phe420 of SEQ ID NO: 2, wherein the amino acid at a position corresponding to position Leu397 of SEQ ID NO:2 is substituted with aspartate, glutamate, or glutamine, and wherein the amino acid corresponding to position Phe420 of SEQ ID NO:2 is substituted with valine or methionine.