Data from: Variable competitive effects of fungicide resistance in field experiments with a plant pathogenic fungus

Classic evolutionary theory suggests that mutations associated with antimicrobial and pesticide resistance result in a fitness cost in the absence of the selective antimicrobial agent or pesticide. There is experimental evidence to support fitness costs associated with resistance to anti-microbial compounds and pesticides across many biological disciplines, including human pathology, entomology, plant sciences, and plant pathology. However, researchers have also found examples of neutral and increased fitness associated with resistance, where the effect of a given resistance mutation depends on environmental and biological factors. We used Zymoseptoria tritici, a model evolutionary plant pathogenic fungus, to compare the competitive ability of fungicide-resistant isolates to fungicide-sensitive isolates. We conducted four large-scale inoculated winter wheat experiments at Oregon State University agriculture experiment stations. We found a significant change in the frequency of fungicide resistance over time in all four experiments. The direction and magnitude of these changes, however, differed by experimental location, year of experiment, and inoculum resistance treatment (fungicide-resistant, resistant/sensitive mixture, and fungicide-sensitive). These results suggest that the competitive ability of resistant isolates relative to sensitive isolates varied depending upon environmental conditions, including the initial frequency of resistant individuals in the population.

经典演化理论表明，与抗菌剂及农药抗性相关的突变，在缺乏选择性抗菌剂或农药的环境下会产生适合度代价（fitness cost）。现有实验证据证实，在人类病理学、昆虫学、植物科学与植物病理学等多个生物学科领域中，抗菌化合物与农药抗性均存在与之关联的适合度代价。不过，研究人员也发现了与抗性相关的中性适合度与适合度提升的案例，即特定抗性突变的效应取决于环境与生物因素。本研究以模式演化植物病原真菌小麦颖枯病菌（Zymoseptoria tritici）为研究对象，对比抗杀菌剂菌株与敏感杀菌剂菌株的竞争能力。我们在俄勒冈州立大学农业试验站开展了四项大型接种冬小麦试验。结果显示，四项试验中杀菌剂抗性频率均随时间发生显著变化。然而，这些变化的方向与幅度因试验地点、试验年份以及接种体抗性处理（抗杀菌剂菌株、抗-敏感混合接种体、敏感杀菌剂菌株）的不同而存在差异。上述结果表明，抗性菌株相较于敏感菌株的竞争能力会随环境条件而异，其中包括种群中抗性个体的初始频率。