Bacterial Diversity Of Western Pacific Seamount And Taxonomic Analysis Of Novel Bacteria

The diversity of microbial species and functional genes has always been a research hotspot for scientists.Deep sea is a ideal source of special microorganisms and new functional genes due to its special and extreme ecological environment.Because of active plate tectonics and undersea volcanism in western Pacific,so speculate there contains a large number of special marine microbial groups.In this study,sea water was collected from 21 stations around the Mariana seamounts.By the method of 16S rDNA sequencing,the diversity and dominant genus of bacteria were preliminarily studied.In addition,two novel species of marine bacteria isolated from the western Pacific seamounts were classified by the method of polyphasic taxonomy.The results showed:369 bacterial strains isolated from Mariana seamounts belonged to 4 phyla,58 genera and 94 species.Among its,?-proteobacteria was the dominant bacterial community with a total of 136 strains(37%).110 strains(30%)distributed in Bacteroidetes,96 strains(26%)distributed in?-proteobacteria,1 strain(0.2%)distributed in?-proteobacteria,14 strains(3.8%)belonged to Firmicute,and 12strains(3%)belonged to Actinobacteria.In 11 dominant generas,Alteromonas was the largest with 11%of strains.5 dominant species belonged to Pelagibaca bermudensis(4.9%),Alteromonas macleodii(4.3%),Halomonas meridian(3.8%),Mesonia mobilis(4.9%),and Muricauda aquimarina(4.3%).In addition,we also found that 11 strains would be the potential novel species and 1 strain would be potential novel genera.By the method of polyphasic taxonomy,two novel bacterial strains of YM319 and YM155 isolated from the western Pacific seamount were identified.The results showed that strain YM319 was a new species of Oceanisphaera,which was isolated from the surface of a black stone with brittle stars.The cells of YM319 were rod-shaped and motile with a single polar flagellum.In addition,strain YM319 could hydrolyse urea,but not casein,DNA,aesculin and starch.Strain YM319 shared highest similarity of 16S rRNA gene sequence with the type strains of O.profunda SM1222~T(97.4%).So,this strain was named Oceanisphaera marina.The strain YM155 isolated from the skin of a aponge was a new species of Thalassotalea.It could hydrolyse DNA,starch,casein,aesculin,gelatin,but not agar and urea.Strain YM155 had the highest similarity of 16S rRNA gene sequence with the type strains of T.piscium T202~T(97.2%)and T.agariperforans M-M1~T(97.2%).So,it was named Thalassotalea profundi.