Seasonal variations of the gut microbiota in the plateau zokor (Eospalax baileyi)

Abstract:

Objective The gut microbiota plays crucial roles in host energy metabolism, immune regulation, and environmental adaptation. However, seasonal variations in the structure, function, and assembly mechanisms of the gut microbiota in the plateau zokor (Eospalax baileyi) remain poorly understood.Methods This study employed Illumina high-throughput sequencing technology to perform 16S rRNA (V3-V4 region) sequencing on 17 gastrointestinal content samples of plateau zokors, thus investigating the effects of season (spring vs. winter) on the diversity, function, and assembly processes of the gut microbiota.Results The alpha diversity and richness of the gut microbiota in plateau zokors were higher in spring than in winter (P<0.05), and the gut microbiota structure in winter exhibited extremely significant differences (P<0.001). At the phylum and genus levels, the relative abundance of certain dominant microbial taxa differed between seasons (P<0.05). PICRUSt functional prediction revealed that at Level 1, metabolism was the dominant pathway, with the genetic information processing, environmental information processing, human diseases, and organismal systems pathways being enriched in the spring group compared with the winter group (P<0.05). Further analysis of metabolic pathways at Level 2 indicated that pathways related to carbohydrate metabolism, amino acid metabolism, nucleotide metabolism, lipid metabolism, metabolism of other amino acids, and metabolism of terpenoids and polyketides were higher in spring than in winter (P<0.05). The neutral community model (NCM) showed more extensive dispersal of the gut microbiota among individuals in winter (Nm=228.75) than in spring (Nm=216.68). The normalized stochasticity ratio (NST) was less than 0.5 in the spring group, indicating dominance by deterministic processes, while it was greater than 0.5 in the winter group, suggesting dominance by stochastic processes, with significant differences between groups (P<0.001). Further iCAMP analysis revealed that drift and dispersal limitation were the primary ecological processes governing microbial community assembly in both seasons, and the relative contributions of these ecological processes differed between spring and winter (P<0.001).Conclusion Season significantly affects the structure, composition, function, and assembly mechanisms of the gut microbiota in plateau zokors. During winter, plateau zokors may save energy by reducing the metabolic activity and information-processing functions of the gut microbiota. In addition, plateau zokors may adjust taxa abundance of the gut microbiota to cope with environmental changes and maintain intestinal homeostasis. These findings provide important insights into the mechanisms by which wild plateau rodents adapt to high-altitude and cold environments from the gut microbiota.