[Soil bacterial community characteristics under different microhabitat types on Maolan karst forest, Guizhou,...

We analyzed the diversity, community composition and relative abundance of soil bacteria communities in five different types of microhabitats (included stone caverns, stone crevices, stone gullies, stone grooves, top-soils) in Maolan karst forest, Guizhou Province, China. Bacterial 16S rRNA V3-V4 variable regions were analyzed by high-throughput sequencing technique. We examined the effects of soil physicochemical factors on bacterial community structure. The results showed that 27 phyla, 64 classes, 128 orders, 242 families, 367 genera, and 704 species were detected in the soils from five types of microhabitats. Proteobacteria, Actinomycetes, Acidobacteria, Chlorofleixi and Nitrospirae were the dominant bacterial phyla. Actinomycetes was the dominant phyla in the microhabitats of top-stone cavern (0-10 cm), sub-stone cavern (10-20 cm), stone crevice, and stone groove. Acidobacteria was the dominant phyla in the top-soil (0-10 cm) and the sub-soil (10-20 cm). Proteobacteria was the dominant phyla in the top-stone gully (0-10 cm) and the sub-stone gully (10-20 cm). The highest soil bacterial Simpson index was found in stone crevice microhabitat, while the lowest was found in sub-soil (10-20 cm) microhabitat. Results from the LEfSe analysis showed that the number of distinct indicator species at the different levels of taxo-nomy was higher in the top-soil (0-10 cm), sub-soil (10-20 cm), sub-stone cavern (10-20 cm), and the stone groove than in the stone crevice, the top-stone gully (0-10 cm) and sub-stone gully (10-20 cm). The indicator phyla were Actinobacteria and Chlorofleixi in the sub-stone cavern (10-20 cm). The top-stone gully (0-10 cm) were characterized by the phyla of Proteobacteria and Tectomicrobia. The top-soil (0-10 cm) was featured by Acidobacteria, Verrucomicrobia and Latescibacteria. The sub-soil (10-20 cm) was dominated by Nitrospirae. There were no indicator species in stone groove, stone crevice, and sub-stone gully (10-20 cm). There was no indicator species in phylum to genus in top-stone cavern (0-10 cm). RDA and ABT analysis showed that soil organic matter, pH, and available phosphorus explained a large part of the variation regarding the responses of bacterial community to the changes in basic physicochemical factors in the soil.