Comparative genome analysis of pathogenic Clavibacter michiganensis strain PF008 causing bacterial canker in pepper with its closely related pathogenic strains of the same species
C. OH (1), I. Hwang (1) (1) Department of Horticultural Biotechnology, Kyung Hee University, Korea; (2) Department of Horticultural Biotechnology, Kyung Hee University, Korea

Clavibacter michiganensis strain PF008 is a Gram-positive plant-pathogenic actinomycete that is the causative agent of bacterial canker in pepper. Although strain PF008 was isolated from a leaf showing bacterial canker symptom in a pepper plant in Korea, it also could cause similar symptom in tomato if artificially inoculated. Recently the whole genome of PF008 was sequenced. In this study, we performed comparative genome analysis with genome information of PF008 and its related C. michiganensis subspecies, mainly subsp. michiganensis strain NCPPB382, to examine virulence factors of strain PF008. Its genome consists of one chromosome (3.056 Mb) and two circular plasmids (39-kb pCM1 and 145-kb pCM2). Strain NCPPB382 has a 130-kb chromosomal pathogenicity island (PAI), consisting of two subregions, chp and tomA subregions, which contain several important virulence genes. However, our study revealed that PF008 lacks this PAI, but most of genes in the chp subregion was found in either pCM1 or pCM2, and the genes of the tomA subregion were missing. More interestingly, PF008 has one cellulase gene (celB) in its chromosome, while NCPPB382 has two cellulase genes, celA and celB, on its chromosome and plasmid. Based on these results, we hypothesize that the presence or absence of PAI region and/or virulence genes on PAI region in either PF008 or NCPPB382 make difference in level of virulence in tomato, and also altered positioning of genes on PAI region between two strains might be occurred by several recombination events during separate evolution in different environment or host plants.

Abstract Number: P12-396
Session Type: Poster