College of Plant Protection, Shandong Agricultural University, Tai'an, China.
Key Laboratory of Pesticide Toxicology and Application Technology, Shandong Agricultural University, Tai'an, China.
Pest Manag Sci. 2019 Dec;75(12):3175-3183. doi: 10.1002/ps.5435. Epub 2019 May 13.
Asia minor bluegrass (Polypogon fugax Nees ex Steud.) is an invasive grass species severely infesting wheat and canola fields in China. In May 2017, a suspected resistant P. fugax population AHHY that survived fenoxaprop-P-ethyl applied at its field-recommended rate was collected from a wheat field in Huaiyuan County, Anhui Province, China. This study aimed to determine the resistance profile of AHHY to acetyl-CoA carboxylase (ACCase) inhibitors and to investigate its mechanisms of resistance to fenoxaprop.
Single-dose testing indicated that the AHHY population had evolved resistance to fenoxaprop. The partial carboxyltransferase domain of ACCase in P. fugax was amplified and compared. Four loci encoding plastidic ACCase were isolated from both the resistant and sensitive individuals. Combining gene sequencing with the derived cleaved amplified polymorphic sequence assay, we found that 100% of the plants of AHHY carried Trp-1999-Ser mutation in their ACCase1,1-2 allele. Whole-plant dose-response bioassay indicated that AHHY was highly resistant to fenoxaprop and pinoxaden (resistance index (RI) ≥ 10) with low resistance to clodinafop-propargyl, sethoxydim, and clethodim (2 ≤ RI < 5). Pre-treatment with piperonyl butoxide largely reduced (55%) the weed's resistance to fenoxaprop. Both basal and fenoxaprop-induced glutathione S-transferases activities toward 1-chloro-2, 4-dinitrobenzene were significantly higher in resistant plants than in susceptible plants.
This study revealed that P. fugax had multiple alleles encoding plastidic ACCase, and reported for the first time the occurrence of Trp-1999-Ser mutation and non-target-site resistance in this species. Fenoxaprop resistance in AHHY plants was conferred by target-site mutation and P450s-involved enhanced metabolism. © 2019 Society of Chemical Industry.
亚洲小茅草（Polypogon fugax Nees ex Steud.）是一种严重侵害中国小麦和油菜田的入侵草种。2017 年 5 月，在中国安徽省怀远县的一个麦田中，采集到了一个对氟吡草酮-乙基在田间推荐剂量下仍具有抗药性的疑似抗性 P. fugax 种群 AHHY。本研究旨在确定 AHHY 对乙酰辅酶 A 羧化酶（ACCase）抑制剂的抗药性特征，并研究其对氟吡草酮的抗药性机制。
单剂量测试表明，AHHY 种群对氟吡草酮产生了抗药性。扩增并比较了 P. fugax 的 ACCase 部分羧基转移酶结构域。从抗性和敏感个体中分离出编码质体 ACCase 的四个基因座。结合基因测序和衍生的切割扩增多态性序列分析，我们发现 AHHY 种群中 100%的植株在其 ACCase1,1-2 等位基因中携带 Trp-1999-Ser 突变。全株剂量反应生物测定表明，AHHY 对氟吡草酮和吡氟禾草灵高度抗药性（抗性指数（RI）≥10），对氯氟吡氧乙酸、精噁唑禾草灵和唑草酮的抗性较低（2≤RI<5）。用增效醚预处理在很大程度上降低了杂草对氟吡草酮的抗性（55%）。与敏感植株相比，抗性植株的基础和氟吡草酮诱导的谷胱甘肽 S-转移酶对 1-氯-2,4-二硝基苯的活性显著升高。
本研究表明 P. fugax 具有多个编码质体 ACCase 的等位基因，并首次报道了该物种中存在 Trp-1999-Ser 突变和非靶标位点抗性。AHHY 植株对氟吡草酮的抗药性是由靶标位点突变和 P450 参与的增强代谢赋予的。 © 2019 英国化学学会。
