Transcriptome and Metabolome Analyses Reveal High-Altitude Adaptation in the Qinghai Toad-Headed Lizard Phrynocephalus vlangalii

The plateau environments are always harsh, with low pressure, low oxygen, and low temperature, which are detrimental to the survival of organisms. The Qinghai toad-headed lizard <i>Phrynocephalus vlangalii</i> has a wide range of altitude adaptation from 2000 to 4600 m. But it is still unclear how organisms maintain tissue function by balancing energy supply and demand changes in high-altitude environments of <i>P. vlangalii</i>. We investigated the plateau metabolic adaptation through transcriptome and metabolome analyses of <i>P. vlangalii</i> from three populations at different altitudes of the Qinghai-Tibet Plateau. The genes related to carbohydrate metabolism were significantly down-regulated at the high altitude. The metabolites alpha-D-glucose 1-phosphate, beta-D-fructose 6-phosphate, D-glycerate 1,3-diphosphate, 3-phosphoglycerate, and phosphoenolpyruvate in glycolysis/gluconeogenesis were down-regulated, too. The lipid metabolic and fatty acid synthase-related genes were up-regulated at a high altitude. In conclusion, the glycogen utilization-related genes and metabolites experienced broad down-regulation, while lipid-related genes and metabolites had a clear trend of up-regulation. Thus, we suggest that <i>P. vlangalii</i> tends to increase lipid utilization and reduce the dependence on glycogen consumption to acclimatize to the high-altitude environment.