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United States Department of Agriculture

Agricultural Research Service

Research Project: POPULATION DYNAMICS AND DISEASE MANAGEMENT OF SOYBEAN ROOT PATHOGENS

Location: Crop Production and Pest Control Research

Title: Molecular mapping and characterization of two genes conferring resistance to Phytophthora sojae in a soybean landrace PI 567139B

Authors
item Lin, Feng -
item Zhao, Meixia -
item Ping, Jieqing -
item Johnson, Austin -
item Zhang, Biao -
item Abney, T -
item Vacant,
item Ma, Jianxin -

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 14, 2013
Publication Date: August 1, 2013
Citation: Lin, F., Zhao, M., Ping, J., Johnson, A., Zhang, B., Abney, T.S., Hughes, T.J., Ma, J. 2013. Molecular mapping and characterization of two genes conferring resistance to Phytophthora sojae in a soybean landrace PI 567139B. Theoretical and Applied Genetics. 126:2177-2185.

Interpretive Summary: Phytophthora root and stem rot (PRR), caused by the soil-borne oomycete pathogen Phytophthora sojae, is one of the most destructive diseases of soybean. PRR can be effectively controlled by race-specific genes conferring resistance to P. sojae, which are designated as Rps. However, Rps genes are usually non-durable, as populations of P. sojae are highly diverse and quick to adapt. Thus, it is important to identify new Rps genes for development of resistant soybean cultivars. PI 567139B is a soybean landrace carrying excellent resistance to nearly all predominant P. sojae races in Indiana. A mapping population consisting of 245 F2 individuals and 403 F2:3 families was developed from a cross between PI 567139B and the susceptible cultivar ‘Williams’, and used to identify the resistance carried by PI567139B. We found that the resistance in PI 567139B was conferred by two independent Rps genes, designated RpsUN1 and RpsUN2. The former was mapped to a region on chromosome 3 that spans the previously identified Rps 1 locus, while the latter was mapped to a region on chromosome 16 upstream of Rps 2. Marker assisted resistance spectrum (MARS) analyses of these genes with 16 isolates of P. sojae, along with the mapping results, suggested that RpsUN1 is a new allele at the Rps1 locus and was renamed Rps1-f, while RpsUN2 is a new Rps gene and was renamed Rps10.

Technical Abstract: Phytophthora root and stem rot (PRR), caused by the soil-borne oomycete pathogen Phytophthora sojae, is one of the most destructive diseases of soybean. PRR can be effectively controlled by race-specific genes conferring resistance to P. sojae (Rps). However, the Rps genes are usually non-durable, as populations of P. sojae are highly diverse and quick to adapt, and can be overcome 8-15 years after deployment. Thus, it is important to identify novel Rps genes for development of resistant soybean cultivars. PI 567139B is a soybean landrace carrying excellent resistance to nearly all predominant P. sojae races in Indiana. A mapping population consisting of 245 F2 individuals and 403 F2:3 families was developed from a cross between PI 567139B and the susceptible cultivar ‘Williams’, and used to dissect the resistance carried by PI567139B. We found that the resistance in PI 567139B was conferred by two independent Rps genes, designated RpsUN1 and RpsUN2. The former was mapped to a 6.5cM region between SSR markers Satt159 and BARCSOYSSR_03_0250 that spans the Rps1 locus on chromosome 3, while the latter was mapped to a 3.0cM region between BARCSOYSSR_16_1275 and Sat_144, 4.4cM upstream of Rps2 on chromosome 16. According to the ‘Williams 82’ reference genome sequence, both regions are highly enriched with NBS-LRR genes. Marker assisted resistance spectrum analyses (MARS) of these genes with 16 isolates of P. sojae, in combination with the mapping results, suggested that RpsUN1 was a novel allele at the Rps1 locus (renamed Rps1-f), while RpsUN2 was a new Rps gene (renamed Rps10).

Last Modified: 8/30/2014