抗苄嘧磺隆雨久花ALS基因突变研究

 【目的】近年来,中国东北水稻田抗药性雨久花发生严重,部分地区用苄嘧磺隆已无法有效控制该杂草的危害。为明确该杂草抗药性发生的根本原因,本试验从分子水平上研究了稻田杂草雨久花（Monochoria korsakowii）对苄嘧磺隆的抗药性机理,以确定导致抗药性产生的乙酰乳酸合成酶（ALS）氨基酸突变位点。【方法】利用PCR技术,通过对抗药性雨久花生物型和敏感性雨久花生物型ALS片段进行扩增和基因克隆,最后对DNA序列进行测序比对。【结果】与敏感性的雨久花ALS相比,抗药性雨久花生物型的ALS共有3处发生突变,即第197位脯氨酸突变为组氨酸,第200位蛋氨酸突变为缬氨酸,第388位精氨酸突变为组氨酸,其中第197位突变与诸多文献报道相符。【结论】抗药性雨久花ALS第197位的突变可能是雨久花对苄嘧磺隆产生抗药性的主要原因。其它2个氨基酸突变是否也导致杂草对苄嘧磺隆产生抗药性未见相关报道,有待进一步研究。

Molecular Basis of Resistance to Bensulfuron-Methyl in Monochoria korsakowii

【Objective】 In recent years, Monochoria korsakowii has been a serious problem in paddy fields in northeast of China. It has become a weed which is very difficult to control by bensulfuron-methyl in some areas in the region. The objective of this study is to understand the molecular basis of the resistance mechanism to bensulfuron-methyl in Monochoria korsakowii and to find the specific mutation sites in amino acid sequence of acetolactate synthase (ALS) in the resistant Monochoria korsakowii biotype. 【Method】Using the PCR method, fragments that encode the ALS were cloned from Monochoria korsakowii, susceptible (S) and resistant (R) biotypes to bensulfuron-methyl respectively, and sequenced subsequently. 【Result】 The result showed that the nucleotide sequence of R M. korsakowii biotype differed from that of the S biotype by three nucleotide substitutions, that were proline (Pro) 197 substituted by histidine (His), methionine (Met) 200 by valine (Val), and arginine (Arg) 388 by histidine (His),among those, the amino acid substitution of Pro197 (CCT) to His (CAT) had been reported in many other resistant weeds. 【Conclusion】 It is clear that the substitution of Pro197 may be responsible for the resistance to bensulfuron-methyl in the R M. korsakowii biotype. The functions of the other two mutations in the R biotype need to be further investigated.