title: Genetic diversity of picocyanobacteria in tibetan lakes: assessing the endemic and universal distributions.
abstract: The phylogenetic diversity of picocyanobacteria in seven alkaline lakes on the Tibetan Plateau was analyzed using the molecular marker 16S-23S rRNA internal transcribed spacer sequence. A total of 1,077 environmental sequences retrieved from the seven lakes were grouped into seven picocyanobacterial clusters, with two clusters newly described here. Each of the lakes was dominated by only one or two clusters, while different lakes could have disparate communities, suggesting low alpha diversity but high beta diversity of picocyanobacteria in these high-altitude freshwater and saline lakes. Several globally distributed clusters were found in these Tibetan lakes, such as subalpine cluster I and the Cyanobium gracile cluster. Although other clusters likely exhibit geographic restriction to the plateau temporally, reflecting endemicity, they can indeed be distributed widely on the plateau. Lakes with similar salinities may have similar genetic populations despite a large geographic distance. Canonical correspondence analysis identified salinity as the only environmental factor that may in part explain the diversity variations among lakes. Mantel tests suggested that the community similarities among lakes are independent of geographic distance. A portion of the picocyanobacterial clusters appear to be restricted to a narrow salinity range, while others are likely adapted to a broad range. A seasonal survey of Lake Namucuo across 3 years did not show season-related variations in diversity, and depth-related population partitioning was observed along a vertical profile of the lake. Our study emphasizes the high dispersive potential of picocyanobacteria and suggests that the regional distribution may result from adaptation to specified environments.
authors.affiliation: CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China yqliu@itpcas.ac.cn huangsijun@scsio.ac.cn.
authors.forename: Sijun
authors.initials: S
authors.lastname: Huang
authors.affiliation: Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China yqliu@itpcas.ac.cn huangsijun@scsio.ac.cn.
authors.forename: Yongqin
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.
authors.forename: Anyi
authors.initials: A
authors.lastname: Hu
authors.affiliation: Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China.
authors.forename: Xiaobo
authors.initials: X
authors.lastname: Liu
authors.affiliation: Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science, Baltimore, Maryland, USA.
authors.forename: Feng
authors.initials: F
authors.lastname: Chen
authors.affiliation: Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China.
authors.forename: Tandong
authors.initials: T
authors.lastname: Yao
authors.affiliation: State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China.
authors.forename: Nianzhi
authors.initials: N
authors.lastname: Jiao
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D044822:Biodiversity; D004269:DNA, Bacterial / Q000235:genetics; D017753:Ecosystem; D014644:Genetic Variation; D060106:Lakes / Q000032:analysis / Q000382:microbiology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D018609:Tibet
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S