Anhui Province key Laboratory of Crop Integrated Pest Management & Anhui Province Engineering Laboratory for Green Pesticide Development and Application, School of Plant Protection, Anhui Agricultural University, Hefei 230036, PR China.
Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China.
Pestic Biochem Physiol. 2024 Jan;198:105711. doi: 10.1016/j.pestbp.2023.105711. Epub 2023 Nov 30.
Severe infestations of American sloughgrass (Beckmannia syzigachne (Steud.) Fernald) in wheat fields throughout Anhui Province, China, pose a significant threat to local agricultural production. This study aims to evaluate the susceptibility of 37 B. syzigachne populations collected from diverse wheat fields in Anhui Province to three commonly used herbicides: fenoxaprop-P-ethyl, mesosulfuron-ethyl, and isoproturon. Single-dose testing revealed that out of the 37 populations, 31, 26, and 11 populations had either evolved or were evolving resistance to fenoxaprop-P-ethyl, mesosulfuron-ethyl, and isoproturon, respectively. Among them, 25 populations displayed concurrent resistance to both fenoxaprop-P-ethyl and mesosulfuron-ethyl, while eight exhibited resistance to all three tested herbicides. Whole-plant bioassays confirmed that approximately 84% of the fenoxaprop-P-ethyl-resistant populations manifested high-level resistance (resistance index (RI) ≥10); 62% of the mesosulfuron-ethyl-resistant populations and 82% of the isoproturon-resistant populations exhibited low- to moderate-level resistance (2 ≤ RI <10). Three distinct target-site mutations were identified in 27% of fenoxaprop-P-ethyl-resistant populations, with no known resistance mutations detected in the remaining herbicide-resistant populations. The inhibition of cytochrome P450s (P450s) and/or glutathione S-transferases (GSTs) substantially increased susceptibility in the majority of resistant populations lacking mutations at the herbicide target site. In conclusion, resistance to fenoxaprop-P-ethyl and mesosulfuron-ethyl was widespread in B. syzigachne within Anhui Province's wheat fields, while resistance to isoproturon was rapidly evolving due to its escalating usage. Target-site mutations were present in approximately one-third of fenoxaprop-P-ethyl-resistant populations, and alternative mechanisms involving P450s and/or GSTs could explain the resistance observed in most of the remaining populations.
安徽省小麦田中严重的美洲狼尾草（Beckmannia syzigachne (Steud.) Fernald）滋生对当地农业生产构成了重大威胁。本研究旨在评估 37 种从安徽省不同小麦田收集的 B. syzigachne 种群对三种常用除草剂的敏感性：精恶唑禾草灵、唑嘧磺草胺和异丙隆。单剂量测试表明，在 37 个种群中，有 31、26 和 11 个种群分别对精恶唑禾草灵、唑嘧磺草胺和异丙隆产生了或正在进化出抗性。其中，25 个种群同时对精恶唑禾草灵和唑嘧磺草胺表现出抗性，8 个种群对三种测试除草剂均表现出抗性。全株生物测定证实，约 84%的精恶唑禾草灵抗性种群表现出高水平抗性（抗性指数（RI）≥10）；62%的唑嘧磺草胺抗性种群和 82%的异丙隆抗性种群表现出低至中水平抗性（2≤RI＜10）。在 27%的精恶唑禾草灵抗性种群中鉴定出了 3 种不同的靶标-site 突变，而在其余具有抗性的种群中未检测到已知的抗性突变。在缺乏除草剂靶标-site 突变的大多数抗性种群中，细胞色素 P450s（P450s）和/或谷胱甘肽 S-转移酶（GSTs）的抑制显著增加了敏感性。综上所述，安徽省小麦田中 B. syzigachne 对精恶唑禾草灵和唑嘧磺草胺的抗性普遍存在，而异丙隆的抗性由于其使用量的增加而迅速进化。靶标-site 突变存在于约三分之一的精恶唑禾草灵抗性种群中，涉及 P450s 和/或 GSTs 的替代机制可以解释大多数其余种群中观察到的抗性。
