安徽省部分地区冬小麦田日本看麦娘Alopecurus japonicus对精噁唑禾草灵的抗性发生现状及ACCase基因突变研究

日本看麦娘Alopecurus japonicus是中国冬小麦田和油菜田主要恶性禾本科杂草之一。为了明确安徽省部分地区日本看麦娘对精齅唑禾草灵抗性发生情况及可能存在的抗性机制，本研究在安徽省天长市日本看麦娘发生严重区域冬小麦田共采集10个种群，采用温室盆栽法在整株水平上测定了不同种群对精齅唑禾草灵的抗性水平，扩增并比对了抗性和敏感种群之间靶标酶乙酰辅酶A羧化酶 (Acetyl-CoA carboxylase，ACCase) 基因部分序列的差异。结果显示，与敏感种群相比，10个抗性种群对精齅唑禾草灵均产生了高水平抗性，抗性指数在30.50~58.55之间。不同抗性种群均发生了ACCase基因突变，其中8个种群发生了第1 781位异亮氨酸 (Ile) 到亮氨酸 (Leu) 突变，2个种群发生了第2 027位色氨酸 (Trp) 到半胱氨酸 (Cys) 突变。此外，各种群均具有较高的ACCase基因突变频率 (≥80%)。研究表明，抗性日本看麦娘在安徽省部分地区发生较为严重，ACCase基因突变是导致不同日本看麦娘种群对精齅唑禾草灵产生抗性的重要原因之一。相对于第2 027位，日本看麦娘ACCase基因更倾向于在第1 781位产生突变以表现靶标抗性。

Resistance status of Japanese foxtail (Alopecurus japonicus) to fenoxaprop-p-ethyl in multiple wheat fields in Anhui Province and involved ACCase gene mutations

Japanese foxtail (Alopecurus japonicus) is a malignant grass weed mainly infesting winter wheat- and canola-growing fields in China. To determine the resistance level and the potential resistance mechanism of A. japonicus to fenoxaprop-p-ethyl, 10 populations of A. japonicus were collected from the wheat fields in Tianchang City, Anhui Province. Whole-plant dose-response experiments were performed to investigate the resistance 1evels of different populations to fenoxaprop-p-ethyl in the greenhouse. Partial sequences of acetyl-CoA carboxylase (ACCase) genes were subsequently amplified, sequenced, and compared between the resistant and susceptible plants. The results revealed that all 10 populations displayed high-level resistance to fenoxaprop-p-ethyl, and the resistance indices ranged from 30.50 to 58.55. Gene sequencing showed that the mutations of isoleucine (Ile) to leucine (Leu) at 1 781 position and tryptophan (Trp) to cysteine (Cys) at 2027 position existed in the ACCase genes of different populations, with eight of them had mutations at 1 781 position. Besides, all populations had mutant frequencies higher than 80%. Our results indicated that herbicide resistance has evolved to a severe stage in Anhui Province, considering that all 10 populations collected from different sites showed high-level resistance to fenoxaprop-p-ethyl. The Ile-1 781-Leu and Trp-2 027-Cys mutations in ACCase genes were very likely to be the key reasons which caused the fenoxaprop-p-ethyl resistance of A. japonicus populations. In addition, compared with 2 027 position, ACCase seems more prone to produce a mutation at 1 781 position in A. japonicus.