Genetic Diversity Of Aerobic Anoxygenic Phototrophic Bacteria In Huguangyan Maar Lake

Maar lake is a special type of Crater Lake. Huguangyan Maar Lake was formed abOTU140k-160k years ago, fully closed, and has not yet been affected by human activities, where abundant and novel microbial species might dwell as reported previously. Aerobic anoxygenic phototrophic bacteria (AAPB) is a functional bacterial group with long evolution history in Earth possessing unique physiological and ecological characteristics. To date, our knowledge about AAPB distribution in Maar Lake is still blank.We chosed the deepest site and gathered samples from three water layers(1m,5m,12m)in four different period. Then we ampliiedy pufM gene encoding the M subunit of anoxygenic photosynthetic reaction centers and pufL gene encoding the L submit of anoxygenic photosynthetic reaction centers. We researched the ecological distribution of AAPB and phylogenetic diversity by the way of constructing library. And combining quantitative Real-time PCR method, it can be calculated the abundance of AAPB in total planktonic bacteria in Huguangyan Maar Lake.The results showed that the diversity of AAPB in Huguangyan Maar Lake is higher. Contrast pufM gene of DNA sequences and RNA sequences, we know it diversity of pufM genes of RNA is higher than the DNA. It showed that it is important to research pufM of RNA to widen the diversity of AAPB in Huguangyan Maar Lake. Phylogenetic and statistical analysis revealed that the dominated AAPB group in Huguangyan Maar Lake which was closely related to β-Proteobacteria. There are a lot of uncultured AAPB similarly to in the Huguangyan and some AAPB that may be unique in Maar lake. Because of the community structure for AAPB was influenced by season, water temperature, pH, light intensity and ultraviolet radiation, the diversity of each layer of AAPB is different. pufL gene may be much more conservative than pufM gene,so the diversity of AAPB of pufL gene is less than pufM gene. Quantitative Real-time PCR results showed the percentage of AAPB in total bacteria in different period and different water layers is irregular and no law can follow.