title: Cytochrome P450 genes induced by bispyribac-sodium treatment in a multiple-herbicide-resistant biotype of Echinochloa phyllopogon.
abstract: BACKGROUND
  Incremental herbicide metabolism by cytochrome P450 monooxygenases (P450s) has been proposed as the basis for resistance to bispyribac-sodium (bispyribac) in a multiple-herbicide-resistant biotype of Echinochloa phyllopogon. Upon exposure to bispyribac, strong induction of bispyribac-metabolising P450 activity has been reported in the resistant line, indicating that P450s induced by bispyribac are involved in the bispyribac resistance.
  
  
  RESULTS
  A polymerase chain reaction (PCR)-based cloning strategy was used to isolate 39 putative P450 genes from the bispyribac-resistant line of E. phyllopogon. Expression analysis by real-time PCR revealed that seven of the isolated genes were upregulated in response to bispyribac treatment of seedlings at the three-leaf stage. The transcript levels and protein sequences of the seven genes were compared between the bispyribac-resistant line and a susceptible line. CYP71AK2 and CYP72A254 were transcribed prominently in the bispyribac-resistant line. Amino acid polymorphisms were found in three genes, including CYP72A254.
  
  
  CONCLUSIONS
  Upregulated expression of these genes is consistent with the inducible herbicide-metabolising P450 activity under bispyribac stress that was reported in a previous study. This is the first study to compare P450 genes in arable weed species in order to elucidate the mechanism for P450-mediated herbicide resistance.
authors: Kyoto University, Graduate School of Agriculture, Kyoto, Japan.
authors: Satoshi
authors: S
authors: Iwakami
authors: Akira
authors: A
authors: Uchino
authors: Yukiko
authors: Y
authors: Kataoka
authors: Hiroyuki
authors: H
authors: Shibaike
authors: Hiroaki
authors: H
authors: Watanabe
authors: Tatsuya
authors: T
authors: Inamura
mesh_terms: D000595:Amino Acid Sequence; D001565:Benzoates / Q000378:metabolism / Q000633:toxicity*; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D031747:Echinochloa / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D053209:Herbicide Resistance / Q000235:genetics*; D011110:Polymorphism, Genetic; D011743:Pyrimidines / Q000378:metabolism / Q000633:toxicity*
chemical_list: D001565:Benzoates; D011743:Pyrimidines; D003577:Cytochrome P-450 Enzyme System; C549011:bispyribac
keywords: ALS inhibitor; herbicide metabolism; herbicide stress response; late watergrass; non-target-site-based resistance