Co-occurrence network and functional profiling of the bacterial community in the industrial pile fermentation of Qingzhuan tea: Understanding core functional bacteria.

The distinct quality of Qingzhuan tea is greatly influenced by the bacterial community but was poorly characterized. Therefore, this study investigated the Co-occurrence network and functional profiling of the bacterial community, with special attention paid to core functional bacteria in the industrial pile fermentation. Microbiomics analysis indicated that Klebsiella and Pantoea dominated raw tea leaves, and were rapidly replaced by Pseudomonas in pile fermentation, but substituted mainly by Burkholderia and Saccharopolyspora in final fermented tea. Bacterial taxa were grouped into 7 modules with the dominant in module I, III, and IV, which were involved in flavor formation and biocontrol production. Functional profiling revealed that "penicillin and cephalosporin biosynthesis" increased in pile fermentation. Twelve bacterial genera were identified as core functional bacteria, in which Klebsiella, Pantoea, and Pseudomonas also dominated the pile fermentation. This work would provide theoretical basis for its chemical biofortification and quality improvement by controlling bacterial communities.