Genetic Characterization of RRS1, a Recessive Locus in Arabidopsis thaliana that Confers Resistance to the Bacterial Soilborne Pathogen Ralstonia solanacearum

Abstract

The soilborne, vascular pathogen Ralstonia solanacearum, the causative agent of bacterial wilt, was shown to infect a range of Arabidopsis thaliana accessions. The pathogen was capable of infecting the Col-5 accession in an hrp-dependent manner, following root inoculation. Elevated bacterial population levels were found in leaves of Col-5, 4 to 5 days after root inoculation by the GMI1000 strain. Bacteria were found predominantly in the xylem vessels and spread systemically throughout the plant. The Nd-1 accession of A. thaliana was resistant to the GMI1000 strain of R. solanacearum. Bacterial concentrations detected in leaves of Nd-1, inoculated with an hrp+ strain of R. solanacearum, were only slightly higher than those detected in the susceptible accession, Col-5, following inoculation with a strain whose hrp gene cluster was deleted. Leaf inoculation of the GMI1000 strain on the resistant accession Nd-1 induced the formation of lesions in the older leaves of the rosette whereas the same strain of R. s...