Fungal biogeographical patterns are key drivers shaping the regional flavor profiles of Chinese strong-flavor Baijiu

Despite the observation of regionally distinct flavor characteristics of Chinese Strong-flavor Baijiu (CSFB) in recent decades, we still lack a comprehensive understanding of how such geography-dependent flavors establish. Here, 168 samples from 8 distilleries were collected across the main production regions of CSFB, and the factors driving the establishment of regional characteristics were investigated by amplicon and metatranscriptome sequencing combined with measurements of climate environments. We demonstrated that microbial communities in both fermented grains and surrounding environments (air and ground) exhibit regional patterns. More importantly, we found the regional patterns of microbial communities at the functional level by contributional diversity analysis. Such microbial and functional patterns correlated with the volatile metabolites profiles of finished fermented grains and predicted the abundance of metabolites in finished fermented grains. Furthermore, we found that climate factors, particularly mean relative humidity, affected fungal rather than bacterial diversity in fermented grains and environments (air and ground), thereby contributing to CSFB regional distinctiveness. Our study provided a basic landscape of the regional patterns of microbiota and metabolites across the main CSFB-producing regions and the dominating shaping factors.