School of Agriculture and Environment, Massey University, Palmerston North, New Zealand.
AgResearch Ltd., Hamilton, New Zealand.
Pestic Biochem Physiol. 2022 Jun;184:105103. doi: 10.1016/j.pestbp.2022.105103. Epub 2022 Apr 20.
Application of herbicides inhibiting acetyl CoA carboxylase (ACCase) has been one of the main strategies for selectively controlling grass weed species such as perennial ryegrass (Lolium perenne L.) in wheat and barley crops in New Zealand. In this study, we have confirmed and characterized resistance to pinoxaden, an ACCase-inhibiting herbicide, in a population of L. perenne. Dose-response experiments were conducted to assess the level of pinoxaden resistance, and based on the LD values, the studied population was 41.4-times more resistant to pinoxaden than a susceptible population. Application of malathion, an inhibitor of the cytochrome P450s, preceding pinoxaden treatment reduced the level of resistance to 9.7-fold. However, pre-treatment with the glutathione S-transferase (GST) inhibitor 4-chloro7- nitrobenzoxadiazole prior to pinoxaden treatment did not affect pinoxaden resistance. Partial sequencing of the ACCase gene revealed that the resistant population had an isoleucine to valine replacement at position 2041. These results suggest that both cytochrome P450-based and target-site mechanisms are jointly associated with this instance of pinoxaden resistance in L. perenne. The pinoxaden-resistant L. perenne individuals were also resistant to quizalofop-p-ethyl (108.6-fold), but they were susceptible to clethodim, which can, therefore, be used to manage this pinoxaden-resistant L. perenne. This is the first report of a L. perenne population in which a rare target-site mutation works in concert with enhanced cytochrome P-450 activity to confer pinoxaden resistance. Evolution of resistance to ACCase-inhibiting herbicides in this L. perenne population indicates that integrated weed management practices are required to prevent widespread resistance developing in New Zealand cereal crop systems.
除草剂抑制乙酰辅酶 A 羧化酶（ACCase）的应用是新西兰小麦和大麦作物中选择性控制多年生黑麦草（Lolium perenne L.）等禾本科杂草的主要策略之一。在本研究中，我们已经证实并表征了对啶磺草胺（一种 ACCase 抑制剂）的抗性，这种抗性存在于多年生黑麦草种群中。进行了剂量反应实验以评估啶磺草胺抗性水平，基于 LD 值，研究种群对啶磺草胺的抗性比敏感种群高 41.4 倍。在施用啶磺草胺之前施用马拉硫磷（一种细胞色素 P450s 的抑制剂）可将抗性水平降低至 9.7 倍。然而，在用啶磺草胺处理之前用谷胱甘肽 S-转移酶（GST）抑制剂 4-氯-7-硝基苯并二恶唑预处理并不会影响啶磺草胺的抗性。ACCase 基因的部分测序表明，抗性种群在 2041 位的异亮氨酸被缬氨酸取代。这些结果表明，细胞色素 P450 为基础的和靶标位点机制都与 L. perenne 中的啶磺草胺抗性有关。啶磺草胺抗性的黑麦草个体也对精喹禾灵（108.6 倍）具有抗性，但对氯氟草醚敏感，因此氯氟草醚可用于管理这种对啶磺草胺具有抗性的黑麦草。这是首例报道的一种黑麦草种群，其中罕见的靶标位点突变与增强的细胞色素 P-450 活性协同作用，赋予啶磺草胺抗性。该黑麦草种群对 ACCase 抑制剂除草剂的抗性进化表明，需要采用综合杂草管理措施来防止新西兰谷类作物系统中广泛产生抗性。
