Effects of an indigenous Lactiplantibacillus plantarum ST starter on microbial function and metabolic profiling of De’ang pickled tea

This study used metagenomics, untargeted metabolomics, and flavoromics to investigate the effects of the indigenous strain Lactiplantibacillus plantarum ST as a starter on the microbial community and metabolite profiles during the fermentation of De’ang pickled tea. The results showed that after ST inoculation, the microbial interaction network and the relative abundance of rare taxa in the pickled tea changed, accompanied by enrichment of genes related to amino acid metabolism pathways. Metabolomics showed that after ST inoculation, amino acids and their derivatives increased, while the volatile metabolite profile changed, with increases in compounds with pleasant fruity and floral notes and decreases in compounds related to musty and waxy odors. Metabolic pathway prediction further suggested that these metabolic changes may be related to the increased relative abundance of rare taxa such as Sphingomonas sp. and Chryseobacterium camelliae . Overall, L. plantarum ST may shape the metabolic and flavor characteristics during De’ang pickled tea fermentation by affecting the microbial community structure and functional potential. These findings provide a theoretical basis for using indigenous L. plantarum as a starter to regulate quality formation in De’ang pickled tea.