Genome-Wide Association Study of Bacterial Blight (Pseudomonas syringae) in Soybean (Glycin max)

Bacterial blight, caused by Pseudomonas syringae, is a common foliar disease of soybean (Glycine max) throughout the northern central regions of USA. Bacterial blight leads to significant yield losses. The objectives of this study were to identify new sources of bacterial blight resistant genes in a diverse panel of 464 soybeans comprised of maturity groups I, II and III and collected from 27 countries including China, Japan, Korea and USA. A genome wide association study (GWAS) was performed using high-density SNP markers, to explore significant markers and identify candidate genes associated with bacterial blight. Variation in the symptom or phenotype expression of bacterial blight was observed among 464 genotypes. Candidate genes known to be associated with bacterial blight resistance were identified on four chromosomes. In the QTL region of Gm06, candidate gene RPS2 encodes a plasma membrane protein that confers resistance to Pseudomonas syringaeinfection by interacting with the avirulence gene avrRpt2. The TXR1 and PETC genes are involved in down-regulation of defense response to bacteria. Disease and abiotic stress resistant genes were also identified.