A Disease Resistance Gene in Arabidopsis with Specificity for the avrPph3 Gene of Pseudomonas syringae pv. phaseolicola. Michael T. Simonich and Roger W. lnnes Department of Biology, Indiana University, Bloomington 47405, U.S.A. MPMI 8:637-640. Accepted 13 March 1995. Copyright 1995 The American Phytopathological Society.

The avirulence gene avrPph3 from Pseudomonas syringae pv. phaseolicola was tested for its ability to convert virulent P. syringae pv. tomato strain DC3000 to avirulence on Arabidopsis. In F₂ plants from a cross between resistant and susceptible ecotypes, the ratio of resistant to susceptible plants was approximately 3:1, indicating that resistance to DC3000(avrPph3) is determined by a single dominant locus, which we have designated RPSS. RPSS was mapped to chromosome 1, between restriction fragment length polymorphism markers m241 and g3786.