华东部分稻区水稻田千金子对氰氟草酯的抗性

采用整株生物测定法检测了华东部分稻区水稻田千金子Leptochloa chinensis (L.) Nees对氰氟草酯的抗性水平并初步探讨了其抗性发生的分子机理。结果表明:与敏感种群 (LC-S) 相比，采自华东部分稻区水稻田的25个千金子种群对氰氟草酯均表现出一定的抗性，其中LC-17-276、LC-17-281、LC-17-282、LC-17-283、LC-17-289和LC-17-290种群的抗性水平较高，抗性指数分别为16、21、27、30、12和15。通过分子手段检测，首次发现在千金子抗性种群LC-17-276中，乙酰辅酶A羧化酶 (acetyl CoA carboxylase，ACCase) 的CT结构域中的色氨酸 (Trp)-1999被丝氨酸 (Ser) 取代，而其他9个被检测的千金子抗性种群却并未发现ACCase的CT结构域位点发生变异。研究表明，华东部分稻区水稻田千金子对氰氟草酯产生了广泛的抗性，其中LC-17-276中ACCase基因的W1999S突变很可能是导致该抗性种群对氰氟草酯产生抗性的重要原因之一。

Resistance of Leptochloa chinensis populations to cyhalofop-butyl in rice fields of eastern China

Whole-plant bioassay experimernts were conducted to investigate the resistance level of Leptochloa chinensis (L.)Nees populations to cyhalofop-butyl in rice fields of eastern China. Results showed that population LC-17-276, LC-17-281, LC-17-282, LC-17-283, LC-17-289 and LC-17-290 had evolved high resistance to cyhalofop-butyl, with resistance index of 16, 21, 27, 30, 12 and 15, respectively. Molecular analyses revealed that the L. chinensis population LC-17-276 has a tryptophan (Trp)-1999-to-serine (Ser) substitution in the CT domain of the ACCase gene, whereas no mutation was detected for the other 9 resistant populations. To the best of our knowledge, this is the first report of Trp-1999-Ser mutation in L. chinensis. These results showed that L. chinensis was extensively resistant to cyhalofop-butyl in some paddy fields in eastern China.