Tian Junhui, Bai Dingyi, He Sifen, Li Zongfang, Bai Lianyang, Pan Lang
College of Plant Protection, Hunan Agricultural University, Changsha 410128, China.
College of Plant Protection, Hunan Agricultural University, Changsha 410128, China.
Pestic Biochem Physiol. 2025 Apr;209:106355. doi: 10.1016/j.pestbp.2025.106355. Epub 2025 Feb 24.
Black-grass (Alopecurus myosuroides), one of the most economically destructive herbicide-resistant weeds in Europe, is rapidly expanding in winter wheat regions of China. In recent years, the recommended application rate of fenoxaprop-P-ethyl in the field has failed to effectively control Alopecurus myosuroides populations, thereby threatening wheat yields at risk. In this study, we collected a suspected herbicide-resistant population (R-HB) of Alopecurus myosuroides from a wheat field in Hebei Province and confirmed its resistance to fenoxaprop-P-ethyl, with a resistance index of 26.73-fold. Sensitivity analyses of other ACCase-inhibiting herbicides revealed cross-resistance in the R-HB population to clethodim and pinoxaden. Molecular analysis indicated that the resistance phenotype in this population was not due to alterations in the target site. Pretreatment with the cytochrome P450 (P450) inhibitor malathion partially reversed fenoxaprop-P-ethyl resistance in the R-HB population. RNA-seq and RT-qPCR validation revealed the constitutive overexpression of the P450 gene CYP71AF43 in the R-HB population. Molecular docking predictions suggest that the CYP71AF43 protein may have metabolic activity toward fenoxaprop-P-ethyl. In genetically modified yeast, overexpression of AmCYP71AF43 was found to enhance tolerance to fenoxaprop-P-ethyl, but not to clethodim and pinoxaden. Additionally, rice calli overexpressing the AmCYP71AF43 gene exhibited resistance to fenoxaprop-P-ethyl, but not to clethodim or pinoxaden. Collectively, the increased expression of CYP71AF43 may enhance P450-mediated metabolism, conferring resistance to fenoxaprop-P-ethyl in the R-HB population. This is the first report of this mechanism in Alopecurus myosuroides. This discovery provides a novel perspective for the in-depth analysis of resistance mechanisms in weeds against the ACCase-inhibiting herbicide fenoxaprop-P-ethyl.
黑麦草（节节麦）是欧洲经济危害最大的抗除草剂杂草之一，目前在中国冬小麦种植区迅速蔓延。近年来，田间精恶唑禾草灵的推荐施用量已无法有效防除节节麦种群，从而威胁到小麦产量。在本研究中，我们从河北省的一块麦田中采集了一个疑似抗除草剂的节节麦种群（R-HB），并确认其对精恶唑禾草灵具有抗性，抗性指数为26.73倍。对其他乙酰辅酶A羧化酶（ACCase）抑制性除草剂的敏感性分析表明，R-HB种群对烯草酮和丙酯草醚存在交叉抗性。分子分析表明，该种群的抗性表型并非由于靶标位点的改变。用细胞色素P450（P450）抑制剂马拉硫磷预处理可部分逆转R-HB种群对精恶唑禾草灵的抗性。RNA测序（RNA-seq）和逆转录定量聚合酶链反应（RT-qPCR）验证显示，R-HB种群中P450基因CYP71AF43组成型过表达。分子对接预测表明，CYP71AF43蛋白可能对精恶唑禾草灵具有代谢活性。在转基因酵母中，发现过表达AmCYP71AF43可增强对精恶唑禾草灵的耐受性，但对烯草酮和丙酯草醚无耐受性。此外，过表达AmCYP71AF43基因的水稻愈伤组织对精恶唑禾草灵具有抗性，但对烯草酮或丙酯草醚无抗性。总体而言，CYP71AF43表达量的增加可能增强P450介导的代谢作用，使R-HB种群对精恶唑禾草灵产生抗性。这是节节麦中该抗性机制的首次报道。这一发现为深入分析杂草对ACCase抑制性除草剂精恶唑禾草灵的抗性机制提供了新的视角。
