Hong Jian, Gao Yangchun, Li Jiaxuan, Ge Yan, Wei Yufeng, Yin Youqiang, Liang Qianru, Gong Shiping
College of Life Science and Technology, Jinan University, Guangzhou, China.
Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Institute of Zoology, Guangdong Academy of Sciences, Guangzhou, China.
Integr Zool. 2025 Jul 17. doi: 10.1111/1749-4877.13011.
Global climate change has heightened heat stress, threatening amphibian and reptile survival, including turtles. Although turtle species vary in heat tolerance, the molecular mechanisms behind these differences are not well understood. This study aimed to identify differentially expressed genes (DEGs) in response to heat stress (32°C) versus normal temperature (25°C) in eight tissues (brain, heart, intestine, liver, lung, muscle, spleen, and stomach) of two turtle species: Platysternon megacephalum (low heat tolerance) and Trachemys scripta elegans (high heat tolerance) using RNA-seq. The results revealed significant down-regulation of genes involved in energy and lipid metabolism in P. megacephalum, suggesting metabolic suppression under heat stress. Furthermore, the jumonji and AT-rich interaction domain containing 2 (JARID2) gene, which regulates cell proliferation and differentiation, was up-regulated in all tissues of P. megacephalum but down-regulated in all tissues of T. scripta elegans under heat stress. Pathway analysis revealed that protein processing in the endoplasmic reticulum was significantly enriched in brain, heart, lung, and muscle tissues of P. megacephalum, with BiP, CHOP, NEF, and HSPs significantly up-regulated in brain tissue, highlighting this pathway's impact on heat stress response. Seven hub genes were identified in the protein processing in the endoplasmic reticulum pathway in P. megacephalum. In contrast, T. scripta elegans showed a moderate response, with up-regulation of ribosomal genes in the brain to enhance protein synthesis and folding, while down-regulation of cell cycle genes in the intestine helped conserve energy for cellular repair. No significant pathways were found in other tissues of T. scripta elegans. These molecular responses in T. scripta elegans likely contribute to its better adaptation to heat stress. This study provides new insights into the molecular mechanisms of heat stress adaptation in turtles, offering valuable knowledge for understanding their ability to cope with future climate change.
全球气候变化加剧了热应激，威胁着两栖动物和爬行动物的生存，包括龟类。尽管龟类物种的耐热性各不相同，但这些差异背后的分子机制尚未得到充分了解。本研究旨在通过RNA测序，鉴定两种龟类：大头平胸龟（耐热性低）和红耳龟（耐热性高）在热应激（32°C）与正常温度（25°C）下八个组织（脑、心脏、肠道、肝脏、肺、肌肉、脾脏和胃）中的差异表达基因（DEG）。结果显示，大头平胸龟中参与能量和脂质代谢的基因显著下调，表明热应激下代谢受到抑制。此外，在热应激下，调节细胞增殖和分化的含jumonji和富含AT的相互作用域2（JARID2）基因在大头平胸龟的所有组织中上调，但在红耳龟的所有组织中下调。通路分析显示，内质网中的蛋白质加工在大头平胸龟的脑、心脏、肺和肌肉组织中显著富集，其中BiP、CHOP、NEF和HSPs在脑组织中显著上调，突出了该通路对热应激反应的影响。在大头平胸龟的内质网蛋白质加工通路中鉴定出七个枢纽基因。相比之下，红耳龟表现出适度的反应，其脑中核糖体基因上调以增强蛋白质合成和折叠，而肠道中细胞周期基因下调有助于为细胞修复保存能量。在红耳龟的其他组织中未发现显著通路。红耳龟的这些分子反应可能有助于其更好地适应热应激。本研究为龟类热应激适应的分子机制提供了新的见解，为理解它们应对未来气候变化的能力提供了有价值的知识。
