ARS | Publication request: Genetic characterization and molecular mapping pse-2 gene for resistance to halo blight in common bean

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 15, 2011
Publication Date: November 1, 2011
Citation: Miklas, P.N., Fourie, D., Wagner, J.J., Larsen, R.C., Chavarro, C., Blair, M., Gepts, P. 2011. Genetic characterization and molecular mapping pse-2 gene for resistance to halo blight in common bean. Crop Science. 51:2439-2448.

Interpretive Summary: Halo bacterial blight is a serious disease limiting bean production worldwide. Genetic resistance in the host is effective for controlling the disease but is not fully understood. We identified a robust gene Pse-2 with broad effect against 7 races of the pathogen. Pse-2 appears to be the most useful gene identified to date for global deployment by breeders to combat this pathogen. This gene was tagged with a molecular marker to simplify breeding for halo blight resistance via marker-assisted selection. It is expected that breeders worldwide will use the marker and gene to breed resistant culitvars for control of this problematic disease.

Technical Abstract: Pseudomonas syringae pv. phaseolicola (Psp) causes ‘Halo Blight’, which is a serious bacterial disease of common bean (Phaseolus vulgaris L.). Several 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 purported to have broad effect against multiple Psp races. – A recombinant inbred population, ZAA 12/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 F2 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 F2 generation. Perhaps other genes are segregating which modify the effect of Pse-2 against Race 8. A SCAR marker tightly linked with Pse-2 was