Internal transcribed spacer sequencing and metatranscriptomics analysis reveal the fungal community composition, diversity related environment variables and roles during serofluid dish fermentation

Abstract

Serofluid dish is a popular fermented food in northwest China that contains abundant microorganisms. Advances of next-generation sequencing facilitate the elucidation of bacterial community composition, yet roles of fungi in serofluid dish need further exploration. Here, internal transcribed spacer (ITS) sequencing and metatranscriptomics were conducted and results showed that the dominant fungal communities belong to Candida and Saccharomyces. Additionally, fungal diversity, including phylogenetic diversity and species richness, was largely correlated with pH, the total organic carbon (TOC) and spatial distance. Multivariate regression tree and all-subsets regression analysis also identified them as strong predictors. Further gene annotations revealed that fungi exhibited higher participation in the carbohydrate metabolism, amino acid metabolism, translation and energy metabolism pathways, including sucrose and maltose metabolism and the production of acetate, fumarate and ethanol. Collectively, fungi in serofluid dish possess rich species diversity, and are affected by both environmental variation and geographical distance. In the fermentation process, fungi predominantly participated in the carbohydrate metabolism and genetic information processing.