Distinct distribution patterns of rare and abundant alkaline phosphatase-harboring bacteria in plateau wetlands

Phosphorus deficiency is a prevailing environmental phenomenon in natural environments and phosphate-solubilizing bacteria, e.g., phosphatase (phoD)-harboring bacteria, can enhance phosphorus availability. Yet, it remains largely unclear about ecological roles and diversity maintenance of rare and abundant phoD-harboring bacteria (PHB) in natural environments. We collected soils and sediments from wetlands on the Tibetan Plateau, and estimated community composition and diversity maintenance of rare and abundant PHB by using Illumina MiSeq sequencing and multiple statistical analyses (e.g., environmental breadth and phylogenetic signal). We found significant decays of community similarities against geographical distance at taxonomic and phylogenetic levels. Rare PHB presented higher α- and β-diversity as well as broader environmental breadths, whereas abundant taxa displayed stronger phylogenetic signals and weaker environmental constraint. Stochastic processes governed PHB community assembly in terms of rare and abundant taxa, and pH played decisive roles in shaping assembly, diversity, and composition of rare and abundant PHB communities. Consequently, community diversity of rare rather than abundant PHB showed significantly negative effect on alkaline phosphatase (ALP) activity, and environmental pH rather than ALP affected more on phosphorus availability. According to abundance and presence-absence analyses, our results emphasized distinct differences in distribution patterns and diversity maintenance mechanisms of rare and abundant PHB. Our findings could help to predict diversity loss of PHB in response to environmental changes, and might guide the environmental protection for wetlands on the Tibetan Plateau via changing environmental pH.