College of Plant Protection, Southwest University, Chongqing City, 400715, People's Republic of China.
Plant Dis. 2020 Apr;104(4):1201-1206. doi: 10.1094/PDIS-07-19-1401-RE. Epub 2020 Feb 17.
is one of the most devastating fungal plant pathogens of oilseed and is distributed worldwide. In particular, stem rot has always been a serious threat to rapeseed production in Chongqing City, China. In this study, simple sequence repeat (SSR) markers and mycelial compatibility groups (MCGs) were used to characterize the population structure of 90 geographic isolates of collected from rapeseed in nine counties of Chongqing. A total of 52 microsatellite haplotypes were identified, and a few haplotypes were found with high frequency. Gene diversity ranged from 0.1570 to 0.4700 in nine populations. A constructed unweighted pair group with arithmetic mean dendrogram based on Nei genetic distance and a STRUCTURE analysis revealed that the genetic composition of the isolates collected in the five counties located in western Chongqing are different from those collected in the two eastern counties, suggesting that breed lines should be cultivated in both the western and eastern regions to effectively evaluate resistance levels. A total of 47 MCGs were identified, and 72% of the MCGs was represented by single isolates. Seven of 13 MCGs that included at least two isolates contained isolates from only one county. SSR haplotypes were not correlated with MCGs. A subset of 34 isolates were inoculated on rapeseed stems, and the aggressiveness showed variation. This research revealed the population genetic structure and aggressiveness of this pathogen in Chongqing, and the results will help to develop disease management and resistance screening strategies.
是一种最具破坏性的真菌植物病原体，分布于世界各地。特别是，茎腐病一直是中国重庆市油菜生产的严重威胁。在这项研究中，使用简单序列重复（SSR）标记和菌丝体相容性群（MCG）来表征从重庆市九个县的油菜中收集的 90 个地理分离物的种群结构。共鉴定出 52 个微卫星单倍型，其中一些单倍型出现频率较高。九个种群的基因多样性范围从 0.1570 到 0.4700。基于 Nei 遗传距离构建的未加权对组算术平均值聚类图和 STRUCTURE 分析表明，位于重庆市西部的五个县采集的分离物的遗传组成与位于东部两个县的分离物不同，这表明应该在西部和东部地区都种植品种，以有效评估抗性水平。共鉴定出 47 个 MCG，其中 72%的 MCG 由单个分离物代表。至少包含两个分离物的 13 个 MCG 中的 7 个仅包含一个县的分离物。SSR 单倍型与 MCG 无关。从 34 个分离物中选择了一部分接种在油菜茎上，其侵袭性表现出差异。这项研究揭示了该病原体在重庆的种群遗传结构和侵袭性，研究结果将有助于制定疾病管理和抗性筛选策略。
