Abstract: In this study, the bacterial diversity and its differences in yak yoghurt collected from agricultural and pastoral areas in Tibet were analyzed by high throughput sequencing technology. The influence of environmental factors on the differences was explored. The results of hierarchical clustering and principal coordinate analysis (PCoA) showed that the microbiota structure of yak yogurt was significantly different between agricultural and pastoral areas. Linear discriminant analysis effect size (LEfSe) analysis showed that the dominant bacterial genera in yak yogurt from both agricultural and pastoral areas were Lactobacillus, Lactococcus and Streptococcus under Firmicutes. The three genera and seven other genera with relatively low abundance were significantly different between yak yogurt samples from the different regions (P < 0.05). Regression analysis and distance-based redundancy analysis (db-RDA) of environmental factors showed that elevation explained the difference between samples more than did average annual temperature. This study provides a reference for further studies on the relationship between the natural environment and the microbial diversity in fermented food in the Qinghai-Tibet plateau and for screening for excellent strains.

Key words: Qinghai-Tibet plateau; yak yogurt; microbial diversity; high-throughput sequencing; 16S rRNA gene