Bacterial diversity in native habitats of the medicinal fungus Ophiocordyceps sinensis on Tibetan Plateau as determined using Illumina sequencing data

Abstract

Ophiocordyceps sinensis is one of the most well-known traditional Chinese medicinal fungi. In this study, bacterial diversity in the soils of native habitats of O. sinensis was investigated using Illumina sequencing data. A total of 525,000 sequences of V6-16S rRNA were analyzed. The number of OTUs from each sample ranged from 13,858 to 15,978 at 97% sequence similarity cut-off. The results demonstrated that the deep sequencing approach provides improved access to rare genotypes. Richness indices and Shannon's diversity index did not differ significantly between samples collected from locations where O. sinensis was present (Os1-3) and not present (NOs1-3). Classified bacterial sequences were grouped into 23 phyla including Proteobacteria, Actinobacteria, Acidobacteria, Verrucomicrobia, etc. The Venn diagram revealed that 7183 OTUs belonging to 14 phyla were shared by Os, NOs and MP (mycelial pellicle wrapping the sclerotium of O. sinensis) samples, possibly representing a core microbiome existing in native habitats of O. sinensis, and that 863 belonging to 12 phyla were shared by Os and MP samples, possibly related to the occurrence of O. sinensis. Overall, the results revealed a high bacterial diversity in the soil samples and the relationships between the bacterial diversity and O. sinensis merit further investigation.

Keywords: 16S rRNA; Illumina deep sequencing technology; Ophiocordyceps sinensis; bacterial diversity; soil.