|QIN, JUN - Virginia Tech|
|SHI, AINONG - University Of Arkansas|
|LI, SONG - Virginia Tech|
|ZHANG, MENGCHEN - Hebei Academy Of Agriculture & Forestry|
|ZHANG, BO - Virginia Tech|
Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2017
Publication Date: 9/14/2017
Citation: Qin, J., Song, Q., Shi, A., Li, S., Zhang, M., Zhang, B. 2017. Genome-wide association mapping of resistance to Phytophthora sojae in a soybean [Glycine max (L.) Merr.] germplasm panel from Maturity Groups IV and V. PLoS One. 12(9):e0814613. https://doi.org/10.1371/journal.pone.0184613.
Interpretive Summary: Phytophthora root rot, caused by a fungus Phytophthora sojaeis, is a major disease of soybean, especially in the areas where soybeans have been cultivated for many years. Yield loss can be substantial, and even entire fields may be destroyed. Utilization of resistant cultivars is the most economical and environmental friendly method to control this disease. At least 13 resistance genes have been reported in soybean, however, most of these genes were identified from soybean germplasm adapted to the North not the South of U.S. Our study established a P. sojae resistance gene panel with high genetic diversity for Southern U.S. soybean breeding programs, and identified a genomic region and candidate genes underlying the host resistance to the disease races 1, 3, 7, 17 and 25 using this panel. The findings in this study will greatly help the Southern soybean breeders to develop commercial varieties with broad genetic diversity and improved P. sojae resistance.
Technical Abstract: Phytophthora sojae, an oomycete pathogen of soybean, causes stem and root rot, resulting in annual economic loss up to $2 billion worldwide. Varieties with P. sojae resistance are environmentally friendly to reduce the disease damages. In order to improve the resistance of P. sojae and broaden the genetic diversity in Southern soybean cultivars and germplasm in U.S., we established a P. sojae resistance gene pool that has high genetic diversity for the exploration of genomic regions underlying host resistance to P. sojae races 1, 3, 7, 17 and 25. A soybean germplasm panel from maturity groups (MGs) IV and V including 189 accessions originated from 10 countries were used in this study. The panel had a high genetic diversity compared to the 6,749 accessions from MGs IV and V in USDA Soybean Germplasm Collection. Based on disease evaluation dataset of these accessions inoculated with P. sojae races 1, 3, 7, 17 and 25, five accessions in this panel were resistant to all races. Genome-wide association analysis identified a total of 32 significant SNPs which were clustered in resistance-associated genomic regions, among these, ss715619920 was only 3kb away from the gene Glyma.14g087500, a subtilisin protease well-known for regulating plant-pathogen responses. Gene expression analysis showed that the gene was down-regulated more than 4 folds in response to P. sojae infection. The identified molecular markers and genomic regions that are associated with the disease resistance in this gene pool will greatly assist the U.S. Southern soybean breeders in developing elite varieties with broad genetic background and P. sojae resistance.