Abstract: To elucidate the expression patterns of antibiotic resistance genes (ARGs) in the gut of plateau pikas (Ochotona curzoniae), this study employed high-throughput metatranscriptomics to analyze gut samples collected along an altitudinal gradient \[low (3694 m), medium (3856 m), and high (4331 m)\] on the Qinghai-Tibet Plateau. A total of 160 highly expressed ARGs were identified. To adapt to energy-limited environments, the gut microbiota primarily adopted low-energy resistance strategies, specifically antibiotic efflux pumps (42.8%) and target alterations (45.9%), whereas energy-intensive antibiotic inactivation mechanisms accounted for only 2%. Six types of high-risk ARGs (e.g.,bacA,ermB, andtetW) were found to be enriched at medium altitude and exhibited significant positive correlations with opportunistic pathogens (e.g.,ComamonasandBacillus), suggesting a potential risk of cross-species transmission. This study revealed the characteristics of the expression of ARGs in the gut of plateau pikas across different altitudinal gradients, providing a scientific basis for assessing the dissemination risk of ARGs among wild mammals in high-altitude ecosystems.

Key words: Ochotona curzoniae, metatranscriptomics, antibiotic resistance genes (ARGs), altitudinal gradient, opportunistic pathogen