抗苄嘧磺隆野慈姑乙酰乳酸合成酶的突变研究

近年来,野慈姑Sagittaria trifolia L.在中国东北稻区发生和危害日趋严重,部分稻区使用苄嘧磺隆已无法有效防除该杂草。为了明确野慈姑抗药性发生的根本原因,本试验从分子水平上对野慈姑抗苄嘧磺隆的机理进行了研究。通过对抗药性(H4)和敏感性(S)野慈姑种群靶标酶乙酰乳酸合成酶(ALS)基因片段进行扩增和克隆,比较其DNA序列的差异,确定导致抗药性产生的ALS氨基酸突变位点。结果表明,与敏感性野慈姑ALS基因相比,H4种群第197位脯氨酸(Pro)突变为苏氨酸(Thr),该位点的突变可能是H4野慈姑种群对苄嘧磺隆产生抗药性的主要原因。ALS第197位Pro突变为Thr致使对苄嘧磺隆产生抗药性是第一次在野慈姑种群中报道。

Mutation in acetolactate synthase of Sagittaria trifolia resistant tobensulfuron-methyl

In recent years, Sagittaria trifolia L. has been a serious problem in paddy fields in northeast of China. It is very difficult to control by bensulfuron-methyl in some areas. The objective of this study is to understand the molecular mechanism of the resistance to bensulfuron-methyl in S. trifolia and to find the specific mutation sites in amino acid sequence of acetolactate synthase (ALS) in the resistant S. trifolia populationS. Fragments encoding the ALS were amplified and cloned from susceptible (S) and resistant (H4) S. trifolia populations to bensulfuron-methyl, respectively, and sequenced subsequently.Sequence analysis showed that H4 population had a mutation at position 197(Pro). The mutation was Pro-197-Thr, which may be responsible for the resistance to bensulfuron-methyl in the S. trifolia population.Pro-197-Thr mutation conferring resistance to bensulfuron-methyl is reported for the first time in S. trifolia.