Abstract:[Background] Temperature plays an important role in shaping soil microbial communities at large scales, but there is a paucity of research on large-scale soil microbial diversity in different temperature zones around the globe. [Objective] To clarify the difference in composition and function of large-scale soil microbes among different temperature zones.[Methods] We used metagenomic technology to analyze the composition and function of soil microbial communities in different temperature zones. [Results] The species diversity of bacteria rose with the increase of latitude of temperature zones, and that of fungi was the highest in temperate zone and lowest in cold zone with absolute dominance of Candida. The abundance of species in the microbial communities also varied greatly among the three temperature zones, with different dominant and special genera. Particularly, the abundance of Pseudomonas and Bacillus was significantly different among the three temperature zones and it increased with the rise of the latitude. However, the abundance of Streptomyces, Geodermatophilus, Rubrobacter, and Micromonospora decreased with increase of latitude of temperature zones. In terms of function, it was found that gene functions related to posttranslational modification, protein turnover, chaperones, intracellular trafficking, secretion, vesicular transport, and cell motility may play an important role in cold tolerance of microorganisms. [Conclusion] This study found that soil microorganisms differed significantly in species diversity, community composition, and function among temperature zones and identified bacteria, fungi, and functions significantly affected by changes in temperature zones, contributing to a large-scale study of the geographic patterns of soil microbial diversity and their formation mechanisms.
