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

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 PI 567139B. 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 6.5 cM region between SSR markers Satt159 and BARCSOYSSR_03_0250 that spans the Rps1 locus on chromosome 3, while the latter was mapped to a 3.0 cM region between BARCSOYSSR_16_1275 and Sat_144, approximately 3.0-3.4 cM 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 of these genes with 16 isolates of P. sojae, in combination with the mapping results, suggested that RpsUN1 was likely to be a novel allele at the Rps1 locus, while RpsUN2 was more likely to be a novel Rps gene.

Fine Mapping of a Resistance Gene RpsHN that Controls Phytophthora sojae Using Recombinant Inbred Lines and Secondary Populations

“…The green line refers to the physical distance between bin249 and bin283, and the red line refers to the fine mapping region. (C) Physical position of the mapped region of RpsHN on chromosome 3 (Lin et al, 2013). …”

Evolutionary Patterns and Coevolutionary Consequences of MIRNA Genes and MicroRNA Targets Triggered by Multiple Mechanisms of Genomic Duplications in Soybean

“…Detection of Mature miRNA, MIRNA Gene, and PEG Expression Small RNAs generated from the susceptible cultivar Williams and its nine NILs (Lin et al, 2013;Zhao et al, 2015) were used to estimate relative abundance (or levels of accumulation) of mature miRNAs. To detect the transcripts of MIRNAs embedded in the host PEGs and splicing sites of the host PEGs, RNA-seq data from 28 samples of soybean (Glycine max) tissues at different developmental stages previously generated (Shen et al, 2014) were retrieved and reanalyzed.…”

QTLomics in Soybean: A Way Forward for Translational Genomics and Breeding

“…Tolerance to Phytophthora root rot is multi-genic due to the presence of several races of pathogen and so far 20 Rps (resistance to P. sojae ) loci including 26 alleles have been detected on four different chromosomes i.e., Gm03, Gm13, Gm16, and Gm18 (Li et al, 2016a). Lin et al (2013) have identified two Rps genes, RpsUN1 on chromosome 3 and RpsUN2 on chromosome 16 from a soybean landrace PI 567139B, which together confer complete resistance to 16 P. sojae races/isolates. Li et al (2016a), further narrowed RpsUN1 and RpsUN2 , to a 151 kb region that harbors five genes including three disease resistance (R)-like genes, and a 36 kb region that contains four genes, all of which are of the typical R-like genes, respectively.…”