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.

经典进化理论指出，与抗菌剂和农药抗药性相关的突变，在缺乏选择性抗菌剂或农药的环境中会产生适合度代价（fitness cost）。目前已有实验证据支持，在人类病理学、昆虫学、植物科学及植物病理学等众多生物学科领域中，抗菌化合物与农药的抗药性均存在相关的适合度代价。然而，研究者也发现了与抗药性相关的适合度中性与适合度提升的案例，即特定抗药性突变的效应取决于环境与生物学因素。本研究以Zymoseptoria tritici（小麦叶枯病菌）——一种进化生物学研究中的模式植物病原真菌——为对象，对比了抗杀菌剂菌株与敏感菌株的竞争能力。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，所有四项试验均观察到，随着时间推移，杀菌剂抗药性的频率发生了显著变化。但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药性处理（抗杀菌剂菌株、抗/敏感菌株混合物、敏感杀菌剂菌株）而异。上述结果表明，相较于敏感菌株，抗性菌株的竞争能力会随环境条件发生变化，其中包括种群中抗性个体的初始频率。