Resources Isolation And Diversity Analysis Of Bacillus-like Species Cultured From Three Tropical Habitat Soils

Hainan Island is located at the northern margin of tropics. Its climate is different from that of typical tropics, which is in the dry and wet tropical climate intermediate belt. The complexity and diversity of geographical environment and eco-environment created rich biodiversity types. Bacillus-like species are common groups of bacteria in soil. They are a kind of endospore-forming aerobic or facultative anaerobic, gram-positive heterotrophic bacteria, widely distributed in various eco-systems. The property of microbial adaptation to environment is mainly relation with enzymes and other bio-active substance. Much interest in Bacillus-like group adaptation has been supported by the search for the applications in biotechnology. So it is very significant not only in theory but also in practice to study.In this study, Bacillus-like bacteria isolated from five soil sampling in three tropical habitats were researched. The results were as follows:In order to isolate the unique resources of Bacillus-like bacteria in Hainan, The dilution soil suspensions with heat bath treatment were spread onto Petri dish for the selective isolation of Bacillus-like species. After preliminary validation through spore staining and removing of the redundant isolates,957strains of spore-forming bacterias were ascertained, there were155isolates from Bamen Bay mangrove,276isolates were collected from Dongzhaigang mangrove, and215strains isolated from tropical high-salt condition (Yinggehai saltern).147strains were isolated from Jiaxi tropical rainforest, and164strains isolated from Jianfengling tropical rainforests.Their genetic diversity, phylogeny and population composition were characterized by16S rDNA PCR-RFLP and16S rDNA sequence analysis. In the level of100%similarity,155isolates in soil from the Bamen Bay mangrove pertained to21clusters, they were distributed in four genera, namely Bacillus, Halobacillus, Virgibacillus and Paenibacillus, of which Bacillus was the dominant one; It was276Bacillus-like bacteria isolated Dongzhaigang mangrove soil that divided into15groups, these isolates mainly concentrates in Bacillus, Halobacillus, Virgibacillus, Gracilibacillus, Oceanobacillus and Lysinibacillus, Bacillus was the dominant group.215isolates in sediment from the tropical high-salt condition (Yinggehai saltern) pertained to30clusters.The culturable Bacillus-like isolates from Yinggehai saltern sediment were mainly distributed in four genera, namely Pontibacillus, Halobacillus, Oceanobacillus and Bacillus, Pontibacillus was the dominant group.147isolates in soil from Jiaxi tropical rainforest habitats pertained to13clusters, which were consist of Bacillus, Paenibacillus, Lysinibacillus, Paucisalibacillus and Bhargavaea, Bacillus was the dominant one. And164isolates in soil from Jianfengling tropical rainforest habitats were belonging to22genotypes that mainly distributed in five genera, namely Bacillus, Lysinibacillus, Paenibacillus, Psychrobacillus and Brevibacillus, Bacillus was the dominant one.Given the above research, there were abundance resources of culturable Bacillus-like species in5soil samples collected from three tropical environments which might exist some new species.16S rDNA sequence analysis of genotype representative strains proved that, the highest similarities of11Bamen Bay and Dongzhaigang mangrove habitats isolates with the corresponding type strain ranged from95.1%to99.0%. The highest similarities of7strains from Yinggehai saltern sediment with the corresponding type strain ranged from97.4%to99.0%, the highest similarities of9potential new species isolated from Jiaxi and jianfengling tropical rainforest habitats with the corresponding type strain were between98.3%and99.0%.