College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China.
Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China.
Pest Manag Sci. 2021 May;77(5):2576-2583. doi: 10.1002/ps.6297. Epub 2021 Feb 12.
Chinese sprangletop (Leptochloa chinensis (L.) Nees) is one of main grass weeds invading Chinese rice fields. The target-site resistance (TSR) of cyhalofop-butyl have been widely reported in L. chinensis populations, but the non-target-site resistance (NTSR) mechanisms have not yet been well-characterized. This study aims to investigate the likely NTSR in a cyhalofop-butyl-resistant L. chinensis population (YZ-R), which was collected from Yangzhou city, Jiangsu Province, China.
Dose-response assays showed the YZ-R population exhibited 191.6-fold resistance to cyhalofop-butyl, compared to the susceptible population (YZ-S). This resistance is not target-site based, because no mutations in the two ACCase genes were detected in the YZ-R plants compared to the YZ-S plants, and the ACCase genes expression levels were similar in YZ-S and YZ-R plants. In addition, the cytochrome P450 inhibitor malathion and piperonyl butoxide (PBO), and glutathione S-transferase (GST) inhibitor 4-chloro-7-nitrobenzoxadiazole (NBD-Cl) did not significantly reverse cyhalofop-butyl resistance in the YZ-R population. However, liquid chromatography-mass spectrometry (LC-MS) analysis indicated that the metabolic rates of cyhalofop acid in YZ-R plants was significantly faster (5 to 10- fold) than in YZ-S plants. Furthermore, the YZ-R population showed no cross-resistance to other ACCase-inhibiting herbicides.
These results indicated that cyhalofop-butyl resistance in the YZ-R population is due to non-target-site based enhanced herbicide metabolism. Resistance in this population is likely involved in a specific detoxification enzyme, with possible high catalytic efficiency and strong substrate specificity, therefore leading to high-level and single resistance to cyhalofop-butyl. © 2021 Society of Chemical Industry.
节节麦（Leptochloa chinensis（L.）Nees）是入侵中国稻田的主要禾本科杂草之一。已广泛报道节节麦种群对氰氟草酯-丁基的靶标部位抗性（TSR），但非靶标部位抗性（NTSR）机制尚未得到很好的描述。本研究旨在研究从中国江苏省扬州市采集的抗氰氟草酯-丁基节节麦种群（YZ-R）中可能存在的非靶标部位抗性（NTSR）机制。
剂量反应试验表明，与敏感种群（YZ-S）相比，YZ-R 种群对氰氟草酯-丁基的抗性提高了 191.6 倍。这种抗性不是基于靶标部位的，因为与 YZ-S 植株相比，YZ-R 植株中没有发现两个 ACCase 基因的突变，并且 YZ-S 和 YZ-R 植株中 ACCase 基因的表达水平相似。此外，用细胞色素 P450 抑制剂马拉硫磷和增效醚（PBO）以及谷胱甘肽 S-转移酶（GST）抑制剂 4-氯-7-硝基苯并恶二唑（NBD-Cl）处理均不能显著逆转 YZ-R 种群对氰氟草酯-丁基的抗性。然而，液相色谱-质谱（LC-MS）分析表明，YZ-R 植株中氰氟草酯酸的代谢率明显更快（5 到 10 倍）。此外，YZ-R 种群对其他 ACCase 抑制型除草剂没有交叉抗性。
这些结果表明，YZ-R 种群对氰氟草酯-丁基的抗性是由于非靶标部位的增强了除草剂代谢。该种群的抗性可能涉及特定的解毒酶，具有可能的高催化效率和强底物特异性，因此导致对氰氟草酯-丁基的高水平和单一抗性。© 2021 英国化学学会。
