[Objective]Tibetan kefir grains（TKGs）,as a traditional fermented product with a long history in Tibet,China,hold a unique position in folk dietary culture.The aim of this study was to utilize metagenomic sequencing technology to analyze the microbial composition and probiotic functions of TKGs,providing a basis for their development and utilization.[Method]TKGs samples were collected from Linzhi,Tibet. After cultivation and DNA extraction,a metagenomic library was constructed by high-throughput sequencing,and bioinformatics analyses were performed using multiple databases.[Result]The sequencing data had high quality and the assembly was successful. Bacteria were the dominant microorganisms in TKGs,with the Lactobacillus group being predominant. Lactobacillus kefiranofaciens accounted for 54% of the total microorganisms,and there were also a small amounts of viruses,eukaryotes and archaea. Lactobacillus phage Llun1 accounted for 5% of the viruses,and Kazachstania exigua accounted for 68% of the fungi. Functional gene annotation revealed that the microbial strains exhibited vigorous metabolic activity,with 1477 genes related to carbohydrate metabolism pathways.The strains also demonstrated strong capabilities in environmental information processing,with 934 genes associated with membrane transport and 503 genes related to signal transduction pathways. While the proportion of genes related to bacterial infectious diseases was relatively low at 12,there were 265 genes associated with antimicrobial drug resistance.Annotations from the CAZy and eggNOG databases revealed that the strain had outstanding carbohydrate metabolism capabilities and overall high metabolic activity.[Conclusion]Metagenomic sequencing had revealed the microbial composition and probiotic functions of TKGs.This study not only emphasized the potential value of TKGs as a natural source of probiotics but also provided a scientific basis for the development and utilization of their probiotic functions.

Tibetan kefir grains（TKGs）  /  metagenomic sequencing  /  microbial composition  /  probiotic function