Genetic Characterization and Molecular Mapping Pse‐2 Gene for Resistance to Halo Blight in Common Bean

Abstract

Pseudomonas syringae pv. phaseoticola (Burkholder) Young et al. {Psp) causes halo blight, which is a serious bacterial disease of common bean {Phaseolus vulgaris L.). Several resistance (R) genes have been discovered in host differential cultivar ZAA 12. Our objectives were to further characterize and enable marker-assisted selection (MAS) of the Pse-2 gene in ZAA 12 purJDorted to have broad effect against multiple Psp races. A recombinant inbred population, ZAA 12 X 'Canadian Wonder', was challenged by the halo blight pathogen differential set consisting of nine Psp races. The resistance conferred by Pse-2 to races 2, 3, 4, 5, 7, 8, and 9 expanded the effect known for this gene from three to seven races. Segregation in Fg populations confirmed dominant inheritance for Pse-2 against all races except Race 8. Resistance to Race 8 was recessively inherited and most closely fit a 7 resistant to 9 susceptible segregation ratio in the Fg generation. Perhaps other genes are segregating that modify the effect of Pse-2 against Race 8. A sequence characterized amplified region (SCAR) marker tightly linked with Pse-2 was generated. The marker was used to integrate Pse-2 to chromosome 10. A survey of lines and cultivars revealed the SCAR will have broad utility for MAS of Pse-2.

Genome-Wide Linkage and Association Mapping of Halo Blight Resistance in Common Bean to Race 6 of the Globally Important Bacterial Pathogen

“…The severe hypersensitive reaction to Race 3 (conferred by Pse-3 ) co-segregated with the I gene locus on Pv02 (48.398–48.534 Mb) (Figure 2C, right graph; Table S1), which is consistent with previous observations (Teverson, 1991; Miklas et al, 2011, 2014). Linked markers show a pattern of segregation distortion in favor of the parent possessing the resistance allele similar to that observed in the RC population (described below).…”

“…Instead, these races mapped the same QTL on Pv10 (3.411–3.457 Mb) that was detected with Races 2, 7, 8, and 9, while an additional QTL was detected with Race 3 on Pv02 (47.368–48.296 Mb). These QTL correspond to race-specific loci Pse-2 (conferring resistance to Races 2, 3, 4, 5, 7, 8, and 9) and Pse-3 (conferring resistance to Races 3 and 4) that were previously mapped in other bean lines (Miklas et al, 2011). This may indicate that CAL 143 contains an alternative race-specific resistance allele in the HB4.2 mapping interval that is tightly linked but functionally distinct from the race-nonspecific allele in PI 150414.…”

“…From the combined data, they proposed a gene-for-gene model involving five major-effect, race-specific plant resistance ( R ) genes and corresponding pathogen avirulence ( avr ) genes (Taylor et al, 1996b). Subsequent genetic research based on linkage mapping identified the locations of major-effect R genes ( Pse-1 to Pse-6 ) on three chromosomes of P. vulgaris (Pv02, Pv04, and Pv10), which are effective against one or more Psph races (Miklas et al, 2009, 2011, 2014). …”

New Loci Including Pse‐6 Conferring Resistance to Halo Bacterial Blight on Chromosome Pv04 in Common Bean

“…For the recombinant inbred population studied by Miklas et al (2011), complete cosegregation was observed for Pse-3 and the I gene, which conditions an immune response or temperature-dependent HR to Bean common mosaic virus (BCMV) and a temperature-independent HR to Bean common mosaic necrosis virus (BCMNV). For the recombinant inbred population studied by Miklas et al (2011), complete cosegregation was observed for Pse-3 and the I gene, which conditions an immune response or temperature-dependent HR to Bean common mosaic virus (BCMV) and a temperature-independent HR to Bean common mosaic necrosis virus (BCMNV).…”

“…For the recombinant inbred population studied by Miklas et al (2011), complete cosegregation was observed for Pse-3 and the I gene, which conditions an immune response or temperature-dependent HR to Bean common mosaic virus (BCMV) and a temperature-independent HR to Bean common mosaic necrosis virus (BCMNV). Miklas et al (2011) identified Pse-2 as the second gene reported by Teverson (1991) in ZAA 12, in addition to Pse-3, which governed HR to Races 3 and 4. Miklas et al (2011) identified Pse-2 as the second gene reported by Teverson (1991) in ZAA 12, in addition to Pse-3, which governed HR to Races 3 and 4.…”