PLANTS HAVING INCREASED TOLERANCE TO HERBICIDES

The invention relates to a method for controlling undesired vegetation at a plant cultivation site， the method comprising the steps of providing， at said site， a cultivated plant that comprises at least one nucleic acid comprising a nucleotide sequence encoding a mutated protoporphyrinogen oxidase (mut-PPO) which is resistant or tolerant to a PPO inhibiting herbicide and applying to said site an effective amount of said herbicide， wherein the nucleotide sequence of a) comprises the sequence of SEQ ID NO: 1 or 3， or a variant thereof having at least 95% identity to the sequence of SEQ ID NO: 1 or 3， and wherein the encoded mut-PPO is a variant of SEQ ID NO: 2 or SEQ ID NO: 4， in which a) the amino acid at position 397 is Gly， Ala， Ser， Thr， Cys， Val， Ile， Met， Pro， Phe， Tyr， Trp， His， Lys， Arg， Asn， Asp， Glu or Gln; and b) the amino acid at position 420 is Val， Met， Ala， Ile or Leu. The invention further relates to plants having an increased tolerance to PPO inhibiting herbicides， a method for controlling undesired vegetation at said plant cultivation site. The invention also relates to an isolated nucleic acid encoding a mut-PPO polypeptide， a mut-PPO polypeptide that confers an increased resistance or tolerance to a PPO inhibiting herbicide in said plant， a transgenic plant cell， a transgenic plant， a seed produced by a transgenic plant having an increased resistance to a PPO inhibiting herbicide， methods of producing said transgenic plant cells and transgenic plant with an increased resistance to a PPO inhibiting herbicide.