Molecular mechanisms underlying population-specific thermal stress responses in the rice-paddy frog (Fejervarya...

Understanding how species adapt to environmental stress is essential for predicting their resilience to climate change. As ectotherms, amphibians are particularly susceptible to temperature fluctuations. Here, we analyzed liver transcriptomes from 18 individual frogs of Fejervarya multistriata (3 biological replicates × 3 treatments × 2 populations: Guilin, Guangxi, with relatively stable warm temperatures throughout the year, and Jinhua, Zhejiang, with more variable seasonal temperatures) exposed to low (4 °C), high (40 °C), or control (25 °C) conditions. Comparative analyses revealed divergent molecular responses between populations. Guilin frogs exhibited extensive transcriptional shifts (1469 up/1627 down under heat; 804 up/1553 down under cold) enriched for energy metabolism, particularly oxidative phosphorylation (OXPHOS). By contrast, Jinhua frogs showed far fewer DEGs (234 up/267 down under heat; 54 up/13 down under cold), indicating reduced transcriptional plasticity. Taken together, these results demonstrate pronounced population-level differences in transcriptomic responses to thermal stress that are consistent with local climatic regimes. The stronger OXPHOS-associated signature in Guilin suggests enhanced expression-level metabolic flexibility during both heat and cold, whereas the muted response in Jinhua indicates a more conservative strategy. We highlight OXPHOS transcription as a candidate indicator of thermal resilience pending physiological validation, underscoring the value of integrating intraspecific transcriptomic variability into conservation planning under rapid warming.