Abstract Gray mold is the main postharvest disease of pomegranate fruit worldwide caused by Botrytis cinerea. However, recent advances in phylogeny of Botrytis spp. revealed that B. cinerea is a complex species. In this study, in total 150 and 246 Botrytis spp. isolates were collected during 2015 and 2016 from Greek and Californian pomegranate packinghouses, respectively, and used to investigate the disease etiology, the fungal population structure and the fungicide resistance profile of the isolates. Identification of causal agents showed that, both in Greece and California, gray mold of pomegranate is caused by a complex of Botrytis species/groups that includes B. cinerea, B. pseudocinerea and Botrytis group S. B. cinerea sensu stricto was the predominant species associated with the disease, although B. pseudocinerea was also identified at relatively high frequencies. B. pseudocinerea is reported for first time as an agent of the disease on pomegranates. The population structure was investigated using as marker the presence of two transposable elements (TEs, Boty and Flipper). Results showed that boty and transposa isolates (both TEs present) were predominant in the B. cinerea subpopulations in Greece and California, respectively, while vacuma (both TEs absent) and boty isolates were found to be predominant in the B. pseudocinerea subpopulations. Measurements of fungicide sensitivity revealed the complete absence of fungicide resistance in the fungal population originating from Greece, while in the Californian subpopulations high frequencies of fungicide resistance were observed in B. cinerea sensu stricto isolates but not in B. pseudocinerea and B. cinerea group S. The higher frequencies of resistance were observed for QoIs, SDHIs and benzimidazoles. In summary, this study provided a description of the structure of Botrytis species complex on pomegranate fruit in 2 different geographic regions of the world and on their fungicide resistance status that will be useful for a better adaptation of the disease control strategies and a better understanding of the risk for fungicide resistance development.

中文翻译：

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Botrytis spp. 的遗传结构和杀菌剂抗性特征。导致希腊和加利福尼亚石榴果实采后灰霉病的种群

摘要 灰霉病是世界范围内由灰葡萄孢引起的主要石榴果实采后病害。然而，Botrytis spp 系统发育的最新进展。揭示 B. cinerea 是一个复杂的物种。在这项研究中，总共有 150 和 246 Botrytis 属。2015 年和 2016 年分别从希腊和加利福尼亚的石榴包装厂收集了分离株，用于研究分离株的疾病病因、真菌种群结构和杀菌剂抗性特征。病原体鉴定表明，在希腊和加利福尼亚，石榴灰霉病是由包括 B. cinerea、B.pseudocinerea 和 Botrytis group SB cinerea sensu stricto 在内的 Botrytis 种/群的复合体引起的。疾病，虽然 B. 假灰霉病也以相对较高的频率被鉴定出来。B.pseudocinerea 首次被报道为石榴疾病的病原体。使用两种转座因子（TE、Boty 和 Flipper）的存在作为标记来研究种群结构。结果表明，boty 和转座分离株（均存在 TE）分别在希腊和加利福尼亚的 B.cinerea 亚群中占主导地位，而真空（均不存在 TE）和 boty 分离株在 B.pseudocinerea 亚群中占主导地位。杀菌剂敏感性的测量表明，源自希腊的真菌种群完全不存在杀菌剂抗性，而在加利福尼亚亚群中，在严格的 B. cinerea sensu stricto 分离株中观察到了高频率的杀菌剂抗性，但在 B. 假灰霉属和 B.灰霉属 S 组。观察到 QoI、SDHI 和苯并咪唑的耐药频率较高。总之，本研究描述了世界上 2 个不同地理区域石榴果实上葡萄孢属菌群的结构及其对杀菌剂的抗性状态，这将有助于更好地适应疾病控制策略和更好地了解杀菌剂抗性发展的风险。