Analysis on bacterioplankton community structure in two oligotrophic lakes,Huashen Lake and Zixia Lake

In order to explore the composition of bacterioplankton community in oligotrophic lakes, clone libraries were constructed and analyzed for Huashen Lake and Zixia Lake located in the urban area of Nanjing City, respectively. Results showed that positive clones of Huashen Lake and Zixia Lake were mainly affiliated with Actinobacteria, Cyanobacteria, Alphaproteobacteria, Betaproteobacteria, Bacteroidetes, Planctomycetes, Verrucomicrobia and Gemmatimonadetes. About 75% of total bacterial clones obtained from Huashen Lake and Zixia Lake were higher than 97% of homology with uncultured bacteria in GenBank. Meanwhile, six new freshwater bacterial clusters were found simultaneously in Huashen Lake clone library and Zixia Lake clone library. The present study has broadened our knowledge on bacterioplankton diversity and suggested that the diversity of bacterioplankton in freshwater lakes still needs further study.