Population Structure Among and Within Iowa, Missouri, Ohio, and South Dakota Populations of Phytophthora sojae

• DOI: 10.1094/pdis-04-15-0437-re
• Publication Date: 2015-07-13T19:38:58Z
• Authors: S. Stewart; A. E. Robertson; D. Wickramasinghe; M. A. Draper; A. Michel; A. E. Dorrance
• Keywords: Phytophthora sojae; Population Genetics

Phytophthora root and stem rot, caused by sojae, is an economically important disease of soybean throughout the Midwestern United States. This has been successfully managed with resistance (Rps) genes; however, pathogen populations Midwest have developed virulence to many Rps genes, including those that not deployed. To gain a better understanding processes influence P. sojae evolution, population genetic structure was compared among using one isolate collected from 17, 33, 20 fields in Iowa, Ohio, South Dakota, respectively, as well multiple isolates individual Missouri. Genotypic diversity measured 21 polymorphic microsatellite (simple-sequence repeat) markers. pathotype 15 differentials. For all but three low sample size, there high level moderate genotypic for both comparisons between states within-field variation. None Rps-gene differentials were resistant isolates. There 103 unique multilocus genotypes identified this study only 2 same field. Although no clones more than field, pairwise FST indicated some gene flow within neighboring does occur across region, states. These results suggest strong probability each state may their own or several regional populations, provide further evidence homothallic which be due, part, limited flow, mutation, outcrossing, likely affects success deployment resistance.