Multi-Tissue Transcriptomic Analysis Reveals Tissue-Specific Thermal Responses and Sex-Biased Functional Differentiation in Reproductive Tissues of the Brown Frog (Rana dybowskii).

The brown frog (Rana dybowskii) is an important cold-temperate amphibian species in northeastern China, with considerable ecological and resource value. Because its survival, metabolism, and reproduction are highly sensitive to environmental temperature, elucidating the molecular mechanism's underlying temperature response is of great significance for understanding environmental adaptation and reproductive regulation in amphibians. In this study, R. dybowskii was used as the experimental model, and a multi-tissue transcriptomic analysis was conducted on the brain, liver, spleen, ovary, oviduct, and testis from both females and males under 2 °C and 12 °C conditions to characterize tissue- and sex-specific responses to temperature variation. The results showed that the global transcriptomic landscape of R. dybowskii was primarily driven by tissue type, whereas temperature effects were mainly manifested within individual tissues. The liver, brain, and spleen exhibited pronounced temperature responsiveness in both sexes, with the liver mainly showing metabolic reprogramming-related functional changes. Intersection analysis further revealed that temperature-responsive genes included not only conserved modules shared across tissues but also a large number of tissue-specific genes. Reproductive tissues displayed more pronounced functional divergence: the ovary showed relatively limited transcriptional changes and remained comparatively stable; the oviduct underwent marked transcriptional remodeling, with upregulated genes mainly involved in glycosylation and macromolecule processing, whereas downregulated genes were primarily associated with ribosomes, translation, and RNA splicing; the testis was likewise highly sensitive to temperature changes, with upregulated genes mainly enriched in amino acid metabolism, mitochondrial function, and DNA repair, while downregulated genes were mainly related to cellular structure and intercellular junctions. Collectively, these findings indicate that the molecular adaptation of R. dybowskii to temperature variation is characterized by strong tissue specificity and sex-biased responses in reproductive tissues. This study provides a transcriptomic basis for elucidating the molecular responses to short-term temperature variation is important for understanding environmental sensitivity and reproductive regulation in amphibians.