| description |
The gut microbiota of animals may play a critical role in host adaptation and diversification. The plateau pika (Ochotona curzoniae), a keystone species of the Qinghai-Tibet Plateau, is adapted to cold, hypoxic high-altitude habitats 3000-6000 m above sea level (masl). The plateau pika therefore provides an excellent model for studying how hosts adapt to high altitude environments, how the gut microbiota evolves, and the interplay between the two. In this study, we investigated the gut microbiota of pikas and related species (Glires) distributed throughout the Qinghai-Tibet Plateau and Inner Mongolia grassland. We calculated host phylogeny and divergence times, and used a phylogenetic approach to reconstruct how the plateau pika microbiota has diverged from that of sister species. The pika microbiota has undergone an accelerated rate of differentiation compared to that of other Leporidae species. Relative to the microbiota of low-altitude Daurian pikas (Ochotona daurica, living at altitudes from 1000 to 1400 masl), plateau pika microbiota have acquired higher microbial diversity and evenness, as well as higher abundance of bacteria associated with plant polysaccharide degradation and fermentation. Specifically, PICRUSt predictions of metagenome function demonstrated that microbial genes involved in carbohydrate metabolism and energy metabolism were overrepresented in the pika gut microbiota, and that the relative abundances of these genes were higher in plateau pikas than in Daurian pikas. Network analysis further confirmed that these bacteria are tightly linked with high altitude in plateau pikas. This gut microbiota divergence is most likely a response to the increased energy requirements of pika in harsh environments. This study provides strong evidence supporting that the plateau pika has adapted to high altitude partly via coevolution with its gut microbiota. |