Genome-wide SNP-based association mapping of resistance to Phytophthora sojae in soybean (Glycine max (L.) Merr.)

Phytophthora root rot (PRR) is among the most important soybean ( Glycine max (L.) Merr.) diseases worldwide, and the host displays complex genetic resistance. A genome-wide association study was performed on 337 accessions from the Yangtze-Huai soybean breeding germplasm to identify resistance regions associated with PRR resistance using 60,862 high-quality single nucleotide polymorphisms markers. Twenty-six significant SNP-trait associations were detected on chromosomes 01 using a mixed linear model with the Q matrix and K matrix as covariates. In addition, twenty-six SNPs belonged to three adjacent haplotype blocks according to a linkage disequilibrium blocks analysis, and no previous studies have reported resistance loci in this 441 kb region. The real-time RT-PCR analysis of the possible candidate genes showed that two genes ( Glyma01g32800 and Glyma01g32855 ) are likely involved in PRR resistance. Markers associated with resistance can contribute to marker-assisted selection in breeding programs. Analyses of candidate genes can lay a foundation for exploring the mechanism of P. sojae resistance.