Research Of Microbial Diversity In Polymetallic Nodule Fields And Cobalt-Rich Crust Region,Polyphasic Taxonomy Study On Genus Brevirhabdus

Marine contains the complex topography and special environment for life, which abundant and diverse marine microbes thrive in. The research on marine microorganisms help us learning the evolutionary and adaptive mechanism of microorganisms, the theory evidence of biomineralization and bioactive compound. Our research has focused on microbial community composition and diversity inside nodules and the surrounding sediments, located in Pacific Ocean, via culture-independent and -dependent methods. And polyphasic taxonomy method were applied to identify strain 22DY15T which was isolated from deep-sea sediment sample collected from hydrothermal vent field in the East Pacific Rise.Culture-dependent method was used to enrich bacteria.136 strains were isolated from Polymetallic Nodule Fields, which belong to 51 groups.54 strains were isolated from Cobalt-rich crust area, which belong to 19 groups. The main groups of Polymetallic Nodule Fields and Cobalt-rich crust area were α- and γ-Proteobacteria. The Species richness index (ACE and Chao 1) of Polymetallic Nodule Fields was were higher than Cobalt-rich crust, diversity index (Shannon) as well. Some strains may participate the process of Manganese-Oxidizing. Some strains share low sequence similarity, and following polymorphic taxonomy research indicate it represent new genus.Through culture independent method, total 1013 near full-length bacterial 16S rRNA gene sequences and 640 archaeal 16S rRNA gene sequences from nodules and surrounding sediments. The 1013 bacterial sequences represented 414 unique bacterial OTUs that were classified to 15 phyla,8 uncultured phylogenetic groups and an unclassified group. Proteobacteria is the main phylum in each library. The 640 archaeal 16S rRNA gene sequences were grouped into 31 OTUs which belong to Thaumarchaeota and Euryarchaeota. Thaumarchaeota were dominant in the archaeal communities, containing 627 sequences grouped into 21 OTUs. Euryarchaeota included 13 sequences grouped into 10 OTUs, which shared low similarity between others.The identification of strains isolated from a deep-sea sediment sample which collected from a hydrothermal vent field located in the East Pacific Rise was based on the polyphasic taxonomy. The phylogenetic analysis indicates strain 22DY15T is the number of Rhodobacteraceae, initially. On the basis of analysing phenotype, chemical characteristics, physiological and biochemical characteristics, phylogenesis, we recommend 22DY15T represent a novel species in new genus of Brevirhabdus (Brevirhabdus pacifica 22DY15T). The results enriched the microbial resources of East Pacific Ocean.