Study On The Polymorphism Of Bacillus And Classification Of The Silicate Bacterium

128 bacillus strains, kept in Agricultural Center of Culture Collection Chinese Academy of Agriculture (ACCC), were analyzed polymorphism by ISR-PCR and ARDRA with 16S rDNA sequence.The results showed that, there was high genetic diversity among these strains. On the basis of ISR-PCR analysis, 128 strains were divided into 11 groups at the similarity of 77%, the same reference strains were in the same groups, but most of the test strains belong to other groups without reference strains, the result showed that the bacillus strains'ISR sequences had rich differences. The 16S rDNA ARDRA method showed the differences of 16S rDNA sequence among the bacillus, it's result showed that these bacillus strains had obvious differences in 16S rDNA sequences. On the basis of the ARDRA analysis, all the strains were divided into 9 unattached branches at the similarity of 50% The reference strain, Bacillus thuringiensis and Bacillus cereus, belong to 3 different branches, only 12 test strains in others branches without reference strains.On this test in bacillus polymorphism, the Bacillus mucilaginosus have obviously distinguish with typical bacillus, such as Bacillus subtilis and Bacillus cereus.The genetic diversity of 16 salicate bacterium strains from ACCC, together with two reference strains(VKPMB-7519T and VKPMB-7517T ), were analyzed by physiology and biochemistry characteristics, the whole-cell fatty acid analysis, Rep-PCR fingerprinting, ISR sequence, 16S rDNA ARDRA, 16S rDNA phylogenic studies, DNA D+C mol% and DNA-DNA hybridization. The phylogeny of the silicate bacterium were determined by 16S rDNA sequences.The physiology and biochemistry characteristics showed that these silicate bactericums had a richer multiplicity; the whole cell fatty acids method indicated that the C16:00 is the typical fatty acid of the silicate bacterium, andC15:0 anteiso was also important fatty acid, other compositions were differently; The ISR sequence and 16S rDNA ARDRA analysis showed that all the 16 strains were similar to the reference strains expect the 11005 strain; Rep-PCR fingerprinting and 16S rDNA sequencing demonstrated that all the 16 silicate bacteriums were grouped with B. mucilaginosus and the differences was more obvious with B. edaphicus. According to these results, 16 silicate bacteriums were divided into 3 groups.Choose several test strains in different groups to measuring the DNA G+C mol% and the DNA-DNA hybridization with B. mucilaginosus VKMPB-7519T. DNA hybridization analysis demonstrated that the 8 strains in group1 belonged to B. mucilaginosus, the DNA hybridization of group2 and group3 were less than 70% with the reference strains B.mucilaginosus, which indicated the 8 strains maybe a new species of bacillus.