Pathotype complexity and genetic characterization of Phytophthora sojae populations in Illinois, Indiana, Kentucky, and Ohio

Phytophthora sojae, the causal agent of Phytophthora root and stem rot of soybean, has been managed with single Rps genes since the 1960’s, but has subsequently adapted to many of these resistance genes, rendering them ineffective. The objective of this study was to examine the pathotype and genetic diversity of P. sojae from soil samples across Illinois, Indiana, Kentucky, and Ohio by assessing which Rps gene(s) were still effective and identifying possible population clusters. There were 218 pathotypes identified from 473 P. sojae isolates with an average of 6.7 out of 15 differential soybean lines exhibiting a susceptible response for each isolate. Genetic characterization of 103 P. sojae isolates from across Illinois, Indiana, Kentucky, and Ohio with 19 simple sequence repeat markers identified 92 multilocus genotypes. There was a moderate level of population differentiation among these four states, with pairwise FST values ranging from 0.026 to 0.246. There was also moderate to hi...

大豆疫霉（Phytophthora sojae）是引发大豆疫霉根腐病的病原菌，自20世纪60年代起，人们便通过单个Rps基因（Rps gene）对该病害进行防控，但该病原菌后续逐渐克服了多数这类抗病基因，致使其丧失防病效果。本研究旨在分析采自伊利诺伊州、印第安纳州、肯塔基州及俄亥俄州土壤样本中的大豆疫霉的致病型与遗传多样性，通过评估哪些Rps基因仍具备防病有效性，以明确其可能的种群聚类特征。研究从473株大豆疫霉分离物中鉴定出218种致病型，每株分离物在15个鉴别大豆品系中平均有6.7个表现出感病反应。本研究利用19个简单序列重复（simple sequence repeat, SSR）标记，对采自上述四个州的103株大豆疫霉分离物开展遗传特征分析，共鉴定得到92种多位点基因型。四个州间的种群分化程度处于中等水平，两两FST值介于0.026至0.246之间。此外，种群分化程度处于中等至较高（原文此处存在截断）。