Gene mutations endowing herbicide resistance may have negative pleiotropic effects on plant fitness. Quantifying these effects is critical for predicting the evolution of herbicide resistance and developing management strategies for herbicide-resistant weeds. This study reports the effects of the acetohydroxyacid synthase (AHAS) Trp574Leu mutation throughout the life cycle of feral radish (Raphanus sativus L.). Resistant and susceptible phenotypes responded differently to light and water treatments in relation to germination and emergence. Under light exposure, the resistant phenotype showed higher germination and emergence, but no differences were found in seed dormancy, germination in darkness and emergence from buried seeds or pods. The resistant phenotype showed delayed and reduced seedling emergence relative to the susceptible phenotype under rainfed conditions, but these differences between the phenotypes were not detected in irrigated soil. The phenotypes showed similar relative growth rates and vegetative biomass. However, under wheat competition, resistant plants had 36%–46% less total above-ground biomass, 26%–47% less seeds per plant and 36%–53% less plant yield than susceptible ones, and these differences were more evident at higher plant density. This study provides a better understanding of the ecological fitness cost associated with the AHAS Trp574Leu mutation in feral R. sativus. The fitness costs could reduce the frequency of the resistant allele in areas untreated with AHAS-inhibiting herbicides. Our results suggest that incorporating non-AHAS herbicidal approaches into integrated weed-management programmes and maintaining fence lines and fields margin as refuges of susceptible plants provides an opportunity to minimize or reverse herbicide resistance evolution.

中文翻译：

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东北野生萝卜的AHAS Trp574Leu突变相关的生态适应度成本

赋予除草剂抗性的基因突变可能对植物适应性产生不利的多效性作用。量化这些影响对于预测除草剂抗性的演变以及制定除草剂抗性杂草的管理策略至关重要。这项研究报告了乙酰羟酸合酶（AHAS）Trp574Leu突变在野生萝卜（Raphanus sativusL.）。抗性和易感表型在萌发和出苗方面对光和水处理的反应不同。在光照下，抗性表型表现出较高的发芽和出苗率，但种子休眠，黑暗中发芽和从埋藏的种子或豆荚中出苗均未发现差异。与雨育条件下的敏感表型相比，抗性表型显示出幼苗出苗延迟和减少，但是在灌溉土壤中未检测到这些表型之间的差异。该表型显示相似的相对生长速率和营养生物量。但是，在小麦竞争下，抗病植物的地上总生物量比易感植物少36％–46％，每株种子减少26％–47％，单株产量减少36％–53％，这些差异在较高的植物密度下更加明显。这项研究可以更好地了解与野生型AHAS Trp574Leu突变相关的生态适应度成本R. sativus。在未经AHAS抑制性除草剂处理的地区，健身成本可以降低抗性等位基因的频率。我们的结果表明，将非AHAS除草方法纳入综合杂草管理计划中，并在易感植物的庇护所中保持围栏和田地边缘，为减少或逆转除草剂抗性的发展提供了机会。