title: Genome-wide association mapping of partial resistance to Phytophthora sojae in soybean plant introductions from the Republic of Korea.
abstract: Phytophthora root and stem rot is one of the most yield-limiting diseases of soybean [Glycine max (L.) Merr], caused by the oomycete Phytophthora sojae. Partial resistance is controlled by several genes and, compared to single gene (Rps gene) resistance to P. sojae, places less selection pressure on P. sojae populations. Thus, partial resistance provides a more durable resistance against the pathogen. In previous work, plant introductions (PIs) originating from the Republic of Korea (S. Korea) have shown to be excellent sources for high levels of partial resistance against P. sojae.
  
  
  
  Resistance to two highly virulent P. sojae isolates was assessed in 1395 PIs from S. Korea via a greenhouse layer test. Lines exhibiting possible Rps gene immunity or rot due to other pathogens were removed and the remaining 800 lines were used to identify regions of quantitative resistance using genome-wide association mapping. Sixteen SNP markers on chromosomes 3, 13 and 19 were significantly associated with partial resistance to P. sojae and were grouped into seven quantitative trait loci (QTL) by linkage disequilibrium blocks. Two QTL on chromosome 3 and three QTL on chromosome 19 represent possible novel loci for partial resistance to P. sojae. While candidate genes at QTL varied in their predicted functions, the coincidence of QTLs 3-2 and 13-1 on chromosomes 3 and 13, respectively, with Rps genes and resistance gene analogs provided support for the hypothesized mechanism of partial resistance involving weak R-genes.
  
  
  
  QTL contributing to partial resistance towards P. sojae in soybean germplasm originating from S. Korea were identified. The QTL identified in this study coincide with previously reported QTL, Rps genes, as well as novel loci for partial resistance. Molecular markers associated with these QTL can be used in the marker-assisted introgression of these alleles into elite cultivars. Annotations of genes within QTL allow hypotheses on the possible mechanisms of partial resistance to P. sojae.
authors: Department of Horticulture and Crop Science, The Ohio State University, Columbus, OH, 43210, USA.|Present Address: Pioneer Hi-Bred International Inc., Napoleon, OH, 43545, USA.
authors: Rhiannon
authors: R
authors: Schneider
authors: Center for Applied Plant Sciences, The Ohio State University, Columbus, OH, 43210, USA.
authors: William
authors: W
authors: Rolling
authors: US Department of Agriculture, Soybean Genomics and Improvement Laboratory, Agricultural Research Service, Beltsville, MD, 20705, USA.
authors: Qijian
authors: Q
authors: Song
authors: US Department of Agriculture, Soybean Genomics and Improvement Laboratory, Agricultural Research Service, Beltsville, MD, 20705, USA.
authors: Perry
authors: P
authors: Cregan
authors: Center for Applied Plant Sciences, The Ohio State University, Columbus, OH, 43210, USA.|Department of Plant Pathology, The Ohio State University, Wooster, OH, 44691, USA.
authors: Anne E
authors: AE
authors: Dorrance
authors: Department of Horticulture and Crop Science, The Ohio State University, Columbus, OH, 43210, USA. mchale.21@osu.edu.|Center for Applied Plant Sciences, The Ohio State University, Columbus, OH, 43210, USA. mchale.21@osu.edu.
authors: Leah K
authors: LK
authors: McHale
mesh_terms: D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000737:chemistry*; D060467:Disease Resistance / Q000235:genetics*; D017343:Genes, Plant / Q000276:immunology*; D018745:Genome, Plant; D055106:Genome-Wide Association Study; D058865:Introduced Species; D015810:Linkage Disequilibrium; D010838:Phytophthora / Q000472:pathogenicity* / Q000502:physiology; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D057865:Plant Immunity / Q000235:genetics; D018517:Plant Roots / Q000235:genetics / Q000276:immunology / Q000382:microbiology; D018547:Plant Stems / Q000235:genetics / Q000276:immunology / Q000382:microbiology; D040641:Quantitative Trait Loci; D056910:Republic of Korea; D013025:Glycine max / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D014481:United States
keywords: GWAS; Glycine max; Haplotype; Linkage disequilibrium; Partial resistance; Phytophthora sojae; Single nucleotide polymorphism