Physiological Specialization of Ralstonia solanacearum Strains Isolated from Enshi, Hubei Province

To provide theoretical information for breeding and utilizing bacterial wilt-resistant tobacco cultivars race, biovar and phylotype of Ralstonia solanacearum of tobacco in Hubei province were identified. Diseased plant samples of tobacco bacterial wilt were collected from eight counties of Enshi area in Hubei province, and 54 strains of the pathogen, Ralstonia solanacearum, were isolated from these samples by using the dilution plate isolation method and identified by specific-PCR assay. Based on reactions on six physiological-race hosts, all 54 strains were proved to belong to race 1. On the basis of ability for oxidizing three hexose (lactose,maltose and cellobiose) and three disaccharides (mannitol, sorbitol and dulcite), all strains were identified as biovar III. Phylotype specific multiplex PCR revealved that all 54 isolates, producing both 144 bp and 280 bp amplicons, belonged to R. solanacearum phylotype I.