Microbiota assembly patterns and diversity of nine plateau lakes in Yunnan, southwestern China.

Microbes serve as important components of ecosystem services and biogeochemical processes in plateau lakes. However, the features of microbiota assembly, abundance and diversity in plateau lakes remain unclear. The microbial communities in surface water from nine plateau lakes in Yunnan Plateau, southwestern China, in the dry and rainy seasons were explored using 16S rRNA gene and 18S rRNA gene sequencing. The results showed that the bacterial community compositions were homogeneous while those of micro-eukaryotes were heterogeneous in plateau lakes. In both seasons, the bacterial phyla of Proteobacteria and Actinobacteriota predominated in oligotrophic lakes. The mesotrophic lakes were dominated by Proteobacteria, Actinobacteriota, Bacteroidota and Cyanobacteria. The eutrophic lakes were mainly dominated by Proteobacteria, Actinobacteriota and Cyanobacteria. The phylum SAR_k_norank had the major micro-eukaryotes in these plateau lakes. The alpha-diversity of bacteria declined in the rainy season, while that of micro-eukaryotes varied from lake to lake. The drivers of microbiotic community assembly in the dry season were identified as nutrient level-related factors. In the rainy season, however, the microbiota in oligotrophic lakes were related to nutrient levels. Microbial communities were driven by precipitation in mesotrophic and eutrophic lakes with large water volumes, while those in lakes with small water volumes were regulated by nutrient level-related factors. Our findings pose first and unique insights into the microbiota of the nine plateau lakes in Yunnan Plateau, providing important ecological knowledge for these lakes with different characteristics.