ARS | Publication request: Genetic analysis and identification of DNA markers linked to a novel Phytophthora sojae resistance gene in the Japanese soybean cultivar Waseshiroge

Submitted to: Euphytica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 24, 2011
Publication Date: September 17, 2011
Citation: Sugimoto, T., Yoshida, S., Kaga, A., Hajika, M., Watanabe, K., Aino, M., Tatsuda, K., Yamamoto, R., Matoh, T., Walker, D.R., Biggs, A.R., Ishimoto, M. 2011. Genetic analysis and identification of DNA markers linked to a novel Phytophthora sojae resistance gene in the Japanese soybean cultivar Waseshiroge. Euphytica. 182:133–145. DOI: 10.1007/s10681-011-0525-8p.

Interpretive Summary: Pythophthora sojae is one of the most destructive soybean pathogens in Japan and the United States. The Japanese cultivar Waseshiroge is highly resistant to several P. sojae races in Japan, but little is known about the genetics of its resistance. The objective of this research was to determine how many genes are involved in its resistance and to map the location(s) of the gene(s). Segretation ratios for resistant:succeptible plants indicated that a single gene at or near the Rps1 locus is responsible for resistance. Reaction patterns observed when Waseshiroge and a set of dfifferential cultivars were challenged with Japanese and U.S. Phythophthora isolates showed that Washeshiroge was resistant to four out of five U.S. isolates, and indicated that the Waseshiroge gene at the Rps1 locus is unique. DNA markers flanking this locus can be used for marker-assisted selection to facilitate transfer of the gene to other genetic backgrounds.

Technical Abstract: Glycine max (L.) Merr. cv. Waseshiroge is considered to be strongly resistant to several races of Phytophthora sojae in Japan. In order to characterize the inheritance of Waseshiroge resistance to P. sojae isolates, 42 F2 progeny plants and 94 F7:8 families were produced from crosses between the susceptible cultivar Tanbakuro and Waseshiroge to use as the experimental populations. Chi-square tests fit a 3:1 ratio for resistance and susceptibility among the 42 F2 seedlings. This and the 43:2:43 ratio for resistance, segregation, and susceptibility in the 94 F7:8 families suggested that resistance was controlled by a single dominant gene. Fifteen differential cultivars were challenged with 11 P. sojae isolates to determine whether any of them reacted similarly to Waseshiroge. None of the differentials had an identical reaction pattern to the 11 isolates, indicating that Waseshiroge may contain a novel Rps gene. DNA analysis was carried out on Tanbakuro, Waseshiroge and the 94 F7:8 families. A linkage map was constructed with 17 SSR markers and nine new primer pairs for marker loci linked to Rps1 on soybean chromosome 3 (linkage group N). The closest markers, Satt009 and T000304487l, map 0.9 and 1.6 cM, respectively, on each side of the Rps gene. The results showed that the Rps gene in Waseshiroge is either allelic to Rps1, or resides at a tightly linked locus in a gene cluster. A three-way-contingency table analysis indicated that marker-assisted selection with the two flanking markers could be used in the development of new resistant cultivars.