BackgroundIn spite of the ecological importance of soil microbial communities, very little data is available on different soil microorganism types along altitudinal gradients on a mountain system with a forest ecosystem to identify the distribution patterns of soil microbial diversity and function. This study aimed to determine the diversity patterns of different soil microorganism types (archaea, bacteria, fungi, viruses) along an altitudinal gradient on Mt. Leigong, a typical mid-subtropical mountain forest ecosystem.ResultsThe richness of bacterial, fungal, and virus community changed in a unimodal pattern, while archaeal community changed in a bimodal pattern with increasing altitude. Euryarchaeota and Thaumarchaeota, Proteobacteria and Acidobacteria, Ascomycota and Basidiomycota, Myoviridae and Podoviridae were abundant taxa in archaeal, bacterial, fungal, and virus community, respectively. Amino acid transport and metabolism, and energy production and conversion were the predominant categories as per Nonsupervised Orthologous Groups (NOG) function gene-annotation. Carbohydrate metabolism, global and overview map, and amino acid metabolism, were predominant categories in the Kyoto encyclopedia of genes and genomes-based (KEGG) pathways. Glycosyl transferase and glycoside hydrolase were predominant categories among carbohydrate enzyme-functional genes. Cluster analysis, redundancy analysis, and Network analysis showed obvious differences in composition, structure, and function of different soil microorganism types in the P. massoniana forest on Mt. Leigong.ConclusionsThese results indicate that different soil microorganism types (archaea, bacteria, fungi, viruses) along the altitudinal gradient have an obvious different distribution patterns in the typical mid-subtropical mountain coniferous forest soil.