Botrytis cinerea isolates with multi-fungicide resistance have frequently been isolated from small fruit fields such as strawberries and blackberries. Individual B. cinerea isolates have been found resistant to up to seven chemical classes of fungicides. Fitness costs and less competitiveness have been observed in multi-fungicide resistant isolates, but this has not been examined under field conditions. In the spring of 2016, flowers of field-grown blackberries were either not inoculated or inoculated with B. cinerea isolates sensitive (0CCR), resistant to five or six chemical classes excluding phenylpyrroles (5CCR), or resistant to six or seven chemical classes including phenylpyrroles (6CCR/MDR1h). The experimental field was left unsprayed for the duration of this study and isolates of B. cinerea were collected from flowers and/or fruit in each of the three experimental years. Isolates collected in summer of 2016 revealed resistance phenotypes in each plot closely matching those of the respective inoculum, with 95% 0CCR, 55% 5CCR, and 91% 6CCR/MDR1h isolates recovered from 0CCR, 5CCR, and 6CCR/MDR1h inoculation plots, respectively. In the 2017 and 2018 isolate collections, 6CCR/MDR1h resistance phenotypes were found in plots inoculated and non-inoculated with this phenotype, indicating their persistence and movement between plots. Resistance phenotypes different from the inoculum were also recovered each year, indicating that the inoculum was successfully competing with a native Botrytis population. Despite the competition, 6CCR/MDR1h isolates were recovered in high frequency from all inoculated plots in 2018. G3pdh and mrr1 sequences of 6CCR/MDR1h isolates collected in 2018 were identical to the sequences of the inoculum, indicating that these isolates likely descended from the inoculum. This study demonstrates that isolates carrying multi-fungicide resistant phenotypes, specifically 6CCR/MDR1h, are competitive in the absence of fungicide selection pressure.

中文翻译：

---

三年多抗多杀菌剂灰葡萄孢菌在黑莓种植中的竞争能力

具有多种杀菌剂抗性的灰葡萄孢分离株经常从草莓和黑莓等小果园中分离出来。已发现单个 B. cinerea 分离株对多达七种化学类别的杀菌剂具有抗性。在耐多杀菌剂分离株中观察到适应性成本和竞争力较低，但这尚未在田间条件下进行检查。2016 年春天，田间种植的黑莓的花朵要么没有接种，要么接种了 B. cinerea 分离株敏感 (0CCR)，对除苯吡咯 (5CCR) 以外的五六种化学类别有抗性，或对六七种化学类别（包括苯基吡咯 (6CCR/MDR1h)。在本研究和 B. 在三个实验年中的每一年，从花和/或果实中收集灰霉病。2016 年夏季收集的分离株显示每个地块中的抗性表型与相应接种物的表型密切匹配，分别从 0CCR、5CCR 和 6CCR/MDR1h 接种地块中回收的 95% 0CCR、55% 5CCR 和 91% 6CCR/MDR1h 分离株， . 在 2017 年和 2018 年的分离物集合中，在接种和未接种该表型的地块中发现了 6CCR/MDR1h 抗性表型，表明它们在地块之间的持久性和移动性。与接种物不同的抗性表型每年也恢复，表明接种物成功地与本地灰霉病种群竞争。尽管存在竞争，但 6CCR/MDR1h 分离株在 2018 年从所有接种地块中高频率回收。2018 年收集的 6CCR/MDR1h 分离株的 G3pdh 和 mrr1 序列与接种物的序列相同，表明这些分离物可能是接种物的后裔。该研究表明，在没有杀菌剂选择压力的情况下，携带多杀菌剂抗性表型（特别是 6CCR/MDR1h）的分离株具有竞争力。