Investigation of molecular mechanisms of herbicide resistance to three modes of action was carried out in a population of Apera spica-venti with resistance to herbicides inhibiting acetolactate synthase (ALS), acetyl-CoA-carboxylase (ACCase) and inhibitors of photosystem-II (PSII). Greenhouse experiments were conducted to detect and characterize resistance pattern to pyroxsulam (ALS inhibitor), pinoxaden (ACCase) and chlorotoluron (PSII) using the recommended rate of each herbicide alone and in tank-mix, sequential application and dose–response tests. Metabolic detoxification and/or reduced herbicide uptake and translocation studies were conducted using dose–response tests with the herbicides in combination with malathion. After treatment, leaves from surviving plants were collected for pyrosequencing to identify target-site mutations in specific regions of ALS, ACCase and psbA genes. Among 32 analysed plants, target-site mutations in specific regions were detected for ALS and ACCase gene, but no psbA mutations were found. Dose–response assay showed high resistance factors for pyroxsulam (RF = 269.4), pinoxaden (RF = 66.3), but lower for chlorotoluron (RF = 14.3). Testing for metabolic detoxification by pre-treatment with malathion resulted in an increased susceptibility to pinoxaden in all doses, some increased susceptibility to chlorotoluron at the highest doses and no difference for pyroxsulam. Our results indicate that while target-site mutations were present for ALS and ACCase sites of action, metabolic detoxification does play a role for pinoxaden resistance. This research provided key insights into the resistance mechanisms in Apera spica-venti and will be important for developing control strategies for this weed in the Czech Republic.

中文翻译：

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捷克共和国的 Apera spica-venti 对三种除草剂作用方式产生抗性

研究了在Apera spica-venti种群中对三种作用方式的除草剂抗性的分子机制对抑制乙酰乳酸合酶 (ALS)、乙酰辅酶 A 羧化酶 (ACCase) 和光系统 II (PSII) 抑制剂的除草剂具有抗性。使用每种除草剂单独和桶混、顺序施用和剂量反应试验的推荐用量，进行温室试验，以检测和表征对吡磺草胺（ALS 抑制剂）、匹诺沙登 (ACCase) 和氯甲苯脲 (PSII) 的抗性模式。代谢解毒和/或减少除草剂吸收和易位研究是使用除草剂与马拉硫磷组合的剂量反应试验进行的。处理后，收集存活植物的叶子进行焦磷酸测序，以确定ALS、ACCase和psbA特定区域的靶位点突变基因。在分析的 32 株植物中，在特定区域检测到ALS和ACCase基因的靶位点突变，但没有检测到psbA发现了突变。剂量反应试验显示对吡磺草胺 (RF = 269.4)、品诺沙登 (RF = 66.3) 具有高抗性因素，但对氯甲苯脲 (RF = 14.3) 较低。通过用马拉硫磷预处理进行的代谢解毒测试导致对所有剂量的吡咯沙登的敏感性增加，在最高剂量下对氯甲苯脲的敏感性有所增加，而对于吡磺草胺没有差异。我们的结果表明，虽然 ALS 和 ACCase 的作用位点存在靶位点突变，但代谢解毒确实对匹诺沙登抗性起作用。这项研究提供了对Apera spica-venti抗性机制的关键见解，对于在捷克共和国制定这种杂草的控制策略非常重要。