Response of Aerobic Anoxygenic Phototrophic Bacterial Diversity to Environment Conditions in Saline Lakes and Daotang River on the Tibetan Plateau,NW China

Variations of the pufM gene encoding the M subunit of the photosynthetic reaction center in aerobic anoxygenic phototrophic (AAnP) bacteria] diversity in response to environmental changes were investigated in waters of six aqueous regimes (including Daotang River and five saline/hypersaline lakes on the Tibetan Plateau) representing a full salinity gradient from freshwater to NaCl-saturation. AAnP bacterial community structures responded to salinity change: Gamma-like AAnP community was predominant in freshwater Daotang River (0.01% salinity). AAnP community structure shifted from Loktanella-like sequences of the Alphaproteobacteria in saline Qinghai Lake to Roseobacter-like sequences in hypersaline lakes (Gahai, Xiaochaidan and Charhan). In addition to salinity, other environmental variables (e.g. N and P availability, TOC and/or DOC, and HCO^? ₃/CO^2? ₃ ions) were also important in affecting the pufM gene diversity in hypersaline lakes. These data have important implications for our understanding of the response of AAnP bacterial community to environmental variables in high-altitude aquatic ecosystems.