The Exploitation Of Bacilli Resources From Chinese Traditional Medicines And The Screening Of Antifungal Bacillus

Bacilli strains isolated from different Chinese traditional medicines were studied by numerical taxonomy and 16S rRNA gene sequences analysis, and three of them were found as antifungal strains, which strongly inhibited the spread of cotton Verticillium wilt disease and Fusarium oxysporum f. sp. vasinfectum.Chinese traditional medicine samples were collected from different drugstores. 307 strains of bacilli were isolated and purified from them. The results of the cluster analysis were run by the numerical taxonomy software developed by a graduate student of our laboratory. The analysis was based on 84 phenotypic characteristics after 19 same characteristics were taken out. The strains were clustered together at the similarity level of 55%. They were clustered into 2 groups at the similarity level of 66% and 7 subgroups at 75%. The chosen strains of these subgroups were as follows: B292, B178, V255, B24, B84, V382 and V362.16S rRNA sequences of four chosen strains of subgroup 1, 2, 4 and 5 were analyzed for the study of phylogenetics. The result showed that the four strains had high similarity with other strains of Bacillus and low similarity with strains of other genuses of Bacilli. B178 was most closely related to Bacillus cereus(99% 16S rRNA similarity) and B292 was most closely related to Bacillus subtilis (100% 16S rRNA similarity). B84 was clustered with other type strains of Bacills genus at the similarity level of 91%. B24 was most closely related to Bacillus clarkii and Bacillus alcaophilus (89% 16S rRNA similarity).Three antifungal stains of Bacilli, B110, B184 and B216, were screened. They could strongly inhibit the spread of cotton Verticillium wilt disease and Fusarium oxysporum f. sp. vasinfectum. Based on the morphological and physiological properties, numerical taxonomy and 16S rRNA sequences analysis, the three strains were identified as Bacillus subtilis.