Analysis About The Diversity Of Culturable Bacteria In Three Lakes In Xinjiang Province And Polyphasic Taxonomic Research On Two New Species Of Bacteria

Located in the northwest of China,Xinjiang is the largest province with numerous lakes and diverse environments in China.Due to the remote location and harsh environment,there are huge microbial resources in those lakes.However,recent studies mainly focus on the non-cultured organisms or halophilic bacteria in salt lakes,there are few reports on culturable microbial diversity of those lakes.In this study,the water and soil samples from Kanasi lake(high-altitude freshwater lake),Wulungu lake(brackish lake at the end of the river)and Ayakekumu lake(high-altitude salt lake)were analyzed for the diversity of culturable bacteria through low-temperature oligotrophic cultivation methods.A total of 326 strains of bacteria were obtained.75 strains were isolated from the soil samples of Wunlungu lake,distributed in 31 genera and 43 species.251 strains were isolated from the three lake water samples,belonging to 55 genera and 93 species respectively.At the same time,20 suspected new taxa were isolated,including the 2 potential new genera from Aykekumu lake.The diversity index shows that Ayakekumu lake has the highest diversity of culturable bacteria,followed by Wulungu lake,but its bacterial richness is less than Kanas lake.Based on classification of classes and genera level,the culturable bacterial community structure of Kanas lake and Wulungu lake water samples are relatively similar.This study found that the most diverse genera are Pseudomonas,Sphingopyxis,and Brevundimonas.Alphaproteobacteria and Gammaproteobacteria are the dominant flora of the three lakes,Actinobacteria followed.Bacteroidetes and Firmicutes were the least.The two suspected new taxa were studied and identified by polyphasic taxonomy method to determine their taxonomic status.The strain M3-13~T,isolated from the coastal soil of Zhoushan,was identified as a new species within the genus Marinobacter and named Marinobacter caseinilyticus.The strain LK2115~T,isolated from the water samples of Wulungu lake,was identified as a new species within the genus Sphingopyxis and the study of polyphasic taxonomy needs to be further completed.Through the above research,we shed light on the community structure of the three lakes in Xinjiang and enrich the microbial resources.Moreover,the microorganisms in Ayakekumu lake,a high-altitude salt lake,maybe have unique environmental adaptation,which is expected to pave the way for the discovery of new microbial functions and metabolic pathways.