直播稻田牛筋草对乙酰辅酶A羧化酶类除草剂抗性水平及其分子机制

Resistance of Eleusine indica to acetyl-CoA carboxylase-inhibiting herbicides in direct-seeded rice and its molecular mechanism

为明确直播稻田牛筋草对乙酰辅酶A羧化酶(ACCase)类除草剂的抗药性水平及其抗性产生的分子机制,采用整株生物测定法测定了牛筋草对6种ACCase类除草剂的抗性水平,并分别对抗性种群和敏感种群的ACCase基因部分片段进行了扩增和测序。结果表明:疑似抗性种群SJ-1对唑酰草胺、氰氟草酯、精唑禾草灵、高效氟吡甲禾灵和烯禾啶产生了高水平抗性,其抗性倍数分别为56.6、62.5、128、52.0和16.3;对烯草酮产生了低水平抗性,相对抗性倍数为4.86。将抗性种群和敏感种群的ACCase基因片段序列进行比对分析发现,SJ-1种群ACCase基因2078位氨基酸由天冬氨酸(GAT)突变为甘氨酸(GGT),该位点氨基酸突变可能是其对ACCase类除草剂产生抗药性的主要原因之一。

The objectives of this study were to illuminate the sensitivity of Eleusine indica population in rice field of direct seeding to acetyl-CoA carboxylase(ACCase)-inhibiting herbicides and reveal its molecular resistance mechanism.Whole-plant bioassay showed that the population SJ-1 was highly resistant to metamifop,cyhalofop-butyl,fenoxaprop-p-ethyl,haloxyfop-R-methyl and sethoxydim,with resistance indexes of 56.6,62.5,128,52.0 and 16.3,respectively.And it was slightly resistant to clethodim,with a resistance index of 4.86.By comparing the partial ACCase sequences derived from the resistant and susceptible populations,the SJ-1 population was found to contain one amino acid substitution of aspartate(GAT)for glycine(GGT)at the codon position 2078.This mutation in the ACCase gene might be responsible for the resistance to ACCase-inhibiting herbicides in the resistant population of E.indica.