小麦田日本看麦娘对唑啉草酯的抗药性机制研究

为明确小麦田日本看麦娘对唑啉草酯的抗药性情况及潜在的抗药性机制，应用整株生物测定法测定了采自安徽省、江苏省多个日本看麦娘发生严重地区共19个日本看麦娘种群对唑啉草酯的抗药性水平，并选取6个高抗种群进行ACCase基因测序和GSTs活性测定，比较抗药性、敏感种群间的基因序列和GSTs活性差异，同时测定了AH-29对其他8种除草剂的敏感性。结果显示，9个日本看麦娘种群对唑啉草酯产生了高水平抗性，占被测总数的47.37%，抗性指数在12.70 ~ 38.77之间；种群AH-28、AH-29和JS-15的ACCase基因CT区域第1781位异亮氨酸（ATA）突变为亮氨酸（TTA），种群AH-36和JS-16第2027位色氨酸（TGG）突变为半胱氨酸（TGT），种群AH-34未发现突变；6个高抗种群体内GSTs活性经唑啉草酯处理后均明显高于同处理敏感种群AH-7；种群AH-29均对ACCase抑制剂炔草酯、烯草酮以及ALS抑制剂的甲基二磺隆和氟唑磺隆产生了高水平抗性，抗性指数分别为45.32、29.54、37.53和23.04；对三甲苯草酮产生了中水平抗性，对双草醚和啶磺草胺表现低抗，但对PSII抑制剂异丙隆较为敏感。研究表明，ACCase基因突变与GSTs活性增强是导致日本看麦娘种群对唑啉草酯产生抗药性的重要原因之一。

Study on resistance mechanism of Alopecurus japonicus to pinoxaden in wheat field

In order to clarify the resistance level and possible resistance mechanism of Alopecurus japonicus to pinoxaden in wheat field, the resistance level of 19 A. japonicus populations in Anhui Province and Jiangsu Province to pinoxaden were determined by whole-plant bioassay. The ACCase gene sequencing and GSTs activity determination were performed on the six populations with the highest resistance to compare the difference in gene sequences and GSTs activity between resistant and sensitive populations, and the sensitivity of AH-29 to other eight herbicides was also determined. The results showed that the nine A. japonicus populations had high level resistance to pinoxaden, accounting for 47.37% of the total tested population, and the resistance indices ranged from 12.70 to 38.77. Isoleucine (ATA) was mutated to leucine (TTA) at position 1781 of ACCase gene CT region in AH-28, AH-29 and JS-15, and tryptophan (TGG) to cysteine (TGT) at position 2027 of ACCase gene in AH-36 and JS-16. No mutation was found in population AH-34. The GSTs activity in six resistant populations was higher than that in susceptible population AH-7 after treated with pinoxaden. Population AH-29 showed high level of resistance to the acetyl-CoA carboxylase (ACCase) inhibitor clodinafop-propargyl, clethodim, and acetolactate synthase (ALS) inhibitor mesosulfuron-methyl and flucarbazone-sodium, with RI value of 45.32, 29.54, 37.53 and 23.04, respectively. In addition, AH-29 showed moderate resistance to tralkoxydim, low resistance to bispyribac-sodium and pyroxsulam, but it was sensitive to photosynthetic II (PSII) inhibitor isoproturon. The increases of ACCase gene mutations and the GSTs activity were very likely the reasons resulting in pinoxaden resistance of A. japonicus populations.