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

Abstract

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/CO²⁻ 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.

Keywords:

• aerobic anoxygenic phototrophic (AAnP)
• diversity
• pufM
• salinity
• Tibetan lakes

This research was supported by National Science Foundation of China (40672079) to HD and BY, the 111 projects of China (Nos. B07011 and B08030), 973 Project of China (2006CB701406), China Postdoctoral Science Foundation (20090450457), the Scientific Research Foundation for the Returned Overseas Chinese Scholars, and the Research Funds of the State Key Laboratory of Geological Processes and Mineral Resources of China University of Geosciences – Beijing (GPMR2008K08B and GPMR200844). The authors are grateful to two anonymous reviewers for their constructive reviews which improved the quality of the manuscript.