Key Laboratory of Crop Cultivation Physiology and Green Production of Hebei Province, Institute of Cereal and Oil Crops, Hebei Academy of Agriculture and Forestry Sciences, Shijiazhuang, Hebei 050035, China.
Key Laboratory of Crop Cultivation Physiology and Green Production of Hebei Province, Institute of Cereal and Oil Crops, Hebei Academy of Agriculture and Forestry Sciences, Shijiazhuang, Hebei 050035, China.
Pestic Biochem Physiol. 2023 Aug;194:105488. doi: 10.1016/j.pestbp.2023.105488. Epub 2023 Jun 6.
Digitaria sanguinalis is a competitive and annual grass weed that commonly infests crops across the world. In recent years, the control of D. sanguinalis by nicosulfuron has declined in Hebei Province, China. To determine the resistance mechanisms of D. sanguinalis to nicosulfuron, a population of D. sanguinalis where nicosulfuron had failed was collected from a maize field of Hebei Province, China. Whole-plant dose-response experiments demonstrated that the resistant population (HBMT-15) displayed 6.9-fold resistance to nicosulfuron compared with the susceptible population (HBMT-5). Addition of the glutathione S-transferase (GSTs) inhibitor 4-chloro-7-nitrobenzoxadiazole (NBD-Cl) significantly reduced the resistance level of the HBMT-15 population to nicosulfuron, and the GSTs activity of the HBMT-15 population was higher than the HBMT-5 population after nicosulfuron treatment. In vitro acetolactate synthase (ALS) enzyme experiments revealed that the nicosulfuron I value for the HBMT-15 population was 41 times higher than that of the HBMT-5 population. An Asp to Glu substitution in the ALS gene was identified in the HBMT-15 population. The HBMT-15 population had a moderate (2- to 4-fold) level of cross-resistance to three other ALS inhibitors (imazethapyr, pyroxsulam, and flucarbazone‑sodium), but was susceptible to pyrithiobac‑sodium. This study demonstrated that both an Asp to Glu substitution in the ALS gene and GSTs-involved metabolic resistance to ALS inhibitors coexisted in a D. sanguinalis population.
狗尾草是一种具有竞争性和一年生的草本杂草，普遍侵害世界各地的作物。近年来，中国河北省对狗尾草的烟嘧磺隆防治效果有所下降。为了确定狗尾草对烟嘧磺隆的抗药性机制，从中国河北省的一块玉米田中采集了一个对烟嘧磺隆产生抗药性的狗尾草种群。全株剂量反应实验表明，与敏感种群（HBMT-5）相比，抗性种群（HBMT-15）对烟嘧磺隆表现出 6.9 倍的抗性。添加谷胱甘肽 S-转移酶（GSTs）抑制剂 4-氯-7-硝基苯并恶二唑（NBD-Cl）可显著降低 HBMT-15 种群对烟嘧磺隆的抗性水平，且 HBMT-15 种群在烟嘧磺隆处理后 GSTs 活性高于 HBMT-5 种群。体外乙酰乳酸合酶（ALS）酶实验表明，HBMT-15 种群的烟嘧磺隆 I 值比 HBMT-5 种群高 41 倍。在 HBMT-15 种群中发现了 ALS 基因中的一个 Asp 到 Glu 取代。HBMT-15 种群对另外三种 ALS 抑制剂（咪唑乙烟酸、吡唑嘧磺隆和双环磺草酮钠盐）具有中等水平（2-4 倍）的交叉抗性，但对吡噻菌胺敏感。本研究表明，ALS 基因中的 Asp 到 Glu 取代和 GSTs 参与的 ALS 抑制剂代谢抗性在一个狗尾草种群中同时存在。
