Gut microbiota of desert-dwelling amphibian and reptile (PRJCA025824)

The variation patterns in gut microbial diversity among host species and populations offer valuable insights into the mechanisms underlying environment-host-microbiome interactions. However, some prevalent patterns, such as phylosymbiosis, have not been examined in amphibians and reptiles. Whether geographical gradients shape the gut microbiota of animals remains an open question. Using 194 gut microbial samples of three amphibians and four reptiles inhabiting the Tarim Desert, we revealed the presence of phylosymbiosis in these animals, which was associated with heterogeneous selection and dispersal limitation. Further examination of gut microbial variations between geographical populations of Bufotes pewzowi and Teratoscincus przewalskii unveiled clear geographical patterns, particularly associations with longitude and annual precipitation, which were linked to heterogeneous selection. Interestingly, these species exhibited consistent microbial variations with longitude, suggesting common selective pressures from longitude-related factors on amphibian and reptile microbiota. Finally, we found population divergences in host genetic background, which was also associated with geographical factors. However, this did not account for the geographical pattern in their gut microbiota, suggesting environment-microbe interaction as a potential and independent ecological pathway mediating the impact of environment on animals. Overall, these findings extend our understanding of variation patterns in gut microbiota and shed light on the underlying mechanisms.