马里亚纳海沟挑战者深渊沉积物异养细菌的分离培养及分类鉴定OA

To investigate the diversity of culturable heterotrophic bacteria in deep-sea sediments from the Mariana Trench,this study focused on a sediment core collected from the Challenger Deep at a depth of 10 816 meters on July,2020.Samples from the surface and various depths within the sediment core were selected,and multiple enrichment and isolation techniques were employed to enhance the cultur-ability of marine bacteria from extreme environments.Cultivation was performed at three temperatures(4,16,and 28 ℃)using two solid media(MA and R2A)for direct plating,and three enrichment media(IMB,IMB-DMSP,and IMB-Rpf)for selective cultivation.A total of 517 strains of heterotrophic bac-teria were obtained,and preliminary identification of potentially novel bacterial taxa was conducted based on 16S rRNA gene sequence comparisons.The results revealed that the isolated 517 strains be-longed to 4 phyla(Proteobacteria,Firmicutes,Actinobacteria,and Bacteroidetes),8 classes,30 or-ders,42 families,74 genera,and 144 species.Different enrichment strategies yielded distinct bacterial isolates,with the IMB-Rpf medium enabling the recovery of a broader diversity of microbial species.The addition of revival factors such as DMSP and supernatants from Mcrococcus luteus had selective en-richment effects on various culturable microbial populations in the sediments.Additionally,composi-tional differences in the cultured bacterial species were observed among different sediments depths.51 strains from the 4 phyla represented potential new taxonomic units,including 3 potential new genera and 41 potential new species.Notably,2 strains of them belonged to the class Sphingobacteriia,which have not previously been isolated from Mariana Trench sediments.The research results will provide a substantial resource of deep-sea bacterial strains for future scientific studies and offer new insights into the isolation and cultivation of microorganisms from extreme deep-sea environments.