Australian Herbicide Resistance Initiative, School of Agriculture and Environment, University of Western Australia, Crawley, WA, Australia.
Planfarm, Geraldton, WA, Australia.
Pest Manag Sci. 2024 Mar;80(3):1523-1532. doi: 10.1002/ps.7886. Epub 2023 Nov 25.
Brome grass (Bromus diandrus Roth) is prevalent in the southern and western cropping regions of Australia, where it causes significant economic damage. A targeted herbicide resistance survey was conducted in 2020 by collecting brome grass populations from 40 farms in Western Australia and subjecting these samples to comprehensive herbicide screening. One sample (population 172-20), from a field that had received 12 applications of clethodim over 20 years of continuous cropping, was found to be highly resistant to the acetyl-CoA carboxylase (ACCase)-inhibiting herbicides clethodim and quizalofop, and so the molecular basis of resistance was investigated.
All 31 individuals examined from population 172-20 carried the same resistance-endowing point mutation causing an aspartate-to-glycine substitution at position 2078 in the translated ACCase protein sequence. A wild-type susceptible population and the resistant population had similar expression levels of plastidic ACCase genes. The level of resistance to quizalofop, either standalone or in mixture with clethodim, in population 172-20 was lower under cooler growing conditions.
Target-site resistance to ACCase-inhibiting herbicides, conferred by one ACCase mutation, was selected in all tested brome plants infesting a field with a history of repeated clethodim use. This mutation appears to have been fixed in the infesting population. Notably, clethodim resistance in this population was not detected by the farmer, and a high future incidence of quizalofop resistance is anticipated. Herbicide resistance testing is essential for the detection of evolving weed resistance issues and to inform effective management strategies. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
雀麦（Bromus diandrus Roth）广泛分布于澳大利亚南部和西部地区的作物种植区，对当地的经济造成了严重的破坏。2020 年，我们对来自西澳大利亚 40 个农场的雀麦种群进行了靶向除草剂抗性调查，并对这些样本进行了全面的除草剂筛选。从一个连续种植 20 年、使用了 12 次氯氟草醚的田块中采集的一个样本（种群 172-20）对乙酰辅酶 A 羧化酶（ACCase）抑制剂除草剂氯氟草醚和精喹禾灵表现出高度抗性，因此我们对其抗性的分子基础进行了研究。
种群 172-20 中检测到的 31 个个体都携带相同的抗性赋予突变，导致翻译后的 ACCase 蛋白序列中第 2078 位的天冬氨酸突变为甘氨酸。一个野生型敏感种群和抗性种群的质体 ACCase 基因表达水平相似。在较凉爽的生长条件下，种群 172-20 对精喹禾灵（单独使用或与氯氟草醚混合使用）的抗性水平较低。
在一个有重复使用氯氟草醚历史的田地中，所有被测试的雀麦植株都对 ACCase 抑制剂除草剂表现出靶标抗性，这种抗性是由一个 ACCase 突变赋予的。该突变似乎已经在侵染种群中固定下来。值得注意的是，农民没有检测到该种群对氯氟草醚的抗性，预计未来精喹禾灵的抗性发生率会很高。除草剂抗性测试对于发现不断演变的杂草抗性问题以及制定有效的管理策略至关重要。
