[Correlation of bacterial diversity in rot Chinese cabbage with the habitat].

OBJECTIVE:To investigate the diversity of bacteria in soft rot Chinese cabbage and analyze their correlation with rhizosphere bacteria, we analyzed the bacterial population structures of soft rot Chinese cabbage and the rhizosphere in different habitat. METHODS:Based on the initial medium and artificial Chinese cabbage medium, we isolated the bacteria from soft rot tissues and rhizospheric soils from two typical habitats. According to the analysis of 16S rRNA gene sequence homology, we identified the isolated strains and analyzed the strains population structure. RESULTS:The total bacteria in soft rot tissues were 4.0 x 10(8) cell g(-1) and 1.2 x 10(11) cell g(-1), the number of pure strains were 56 and 85, the dominant strains were Curtobacterium flaccumfaciens pv. flaccumfaciens and Pseudomonas spp. (P. hibiscicola, P. taiwanensis, P. tuomuerensis, P. mosselii). The total bacteria in rhizospheric soils were 2.7 x 10(5) cell g(-1) and 6.2 x 10(7) cell g(-1), the number of pure strains were 36 and 70, the dominant strains were Bacillus megatherium and Pseudomonas spp. (P. plecoglossicida, P. hibiscicola, P. parafulva, P. monteilii, P. geniculata). CONCLUSION:The methods used in this study were effective in analyzing bacterial diversity in soft rot Chinese cabbage and the results correlated well with the soil bacteria analysis, suggesting that soft rot Chinese cabbage may be induced by various environmental bacteria. Our results infer that soft rot of Chinese cabbage might be pathogen-complex, and provide the clues for the mechanism study and protection.