【摘要】 虫黄藻是珊瑚共生体系中不可或缺的伙伴，不同种类的虫黄藻对环境胁迫的敏感性不同，从而影响珊瑚宿主的环境适应能力。本研究从脂质代谢角度，探讨了广泛分布的两种珊瑚共生虫黄藻—环境敏感型Cladocopium goreaui和环境耐受型Durusdinium trenchii在热胁迫下的应激模式。研究发现，热胁迫显著影响两者的生长密度、光合色素含量、称为光系统Ⅱ（PSⅡ）的光化学效率（F_v/F_m）及抗氧化活性，且差异均具有统计学意义（P<0.05）。脂质组学显示，C. goreaui和D.trenchii在应对热胁迫时，磷脂酰胆碱、甘油三酯、磷脂酰乙醇胺和溶血磷脂酰胆碱等脂质差异代谢物显著富集于甘油磷脂代谢、甘油酯代谢及多不饱和脂肪酸相关代谢通路。值得注意的是，两者在鞘脂代谢方面存在显著差异：D. trenchii通过下调神经酰胺水平减少细胞氧化应激损伤，调控自噬过程，并适应膜流动性的变化；而C. goreaui主要通过上调富含多不饱和脂肪酸的脂质分子，以维持膜稳定性和调控信号传导。深入解析不同环境敏感性虫黄藻在热胁迫下的脂质代谢应激机制，有助于从共生伙伴的角度，为提升珊瑚对环境变化的适应能力提供新的见解。更多还原

【Abstract】 Symbiodiniaceae are indispensable partners in the coral symbiotic system, and different species exhibit varying sensitivities to environmental stress, thereby influencing the environmental adaptability of their coral hosts.This study investigates the stress response patterns of two widely distributed coral symbiotic Symbiodiniaceae species—environmentally sensitive Cladocopium goreaui and environmentally tolerant Durusdinium trenchii—under heat stress from the perspective of lipid metabolism. The results showed that heat stress significantly affected their cell density, photosynthetic pigment content, photochemical efficiency of photosystem Ⅱ(F_v/F_m), and antioxidant activity, with statistically significant differences(P < 0.05). Lipidomics revealed that lipid-differentiated metabolites such as phosphatidylcholine, triglycerides, phosphatidylethanolamine and lysophosphatidylcholine were significantly enriched in glycerophospholipid metabolism, triglyceride metabolism, and polyunsaturated fatty acid-related metabolic pathways in response to heat stress in C. goreaui and D. trenchii. Notably, the two species exhibited significant differences in sphingolipid metabolism: D. trenchii downregulated ceramide levels to reduce oxidative stress damage, regulate autophagy, and adapt to changes in membrane fluidity, whereas C. goreaui primarily upregulated lipid molecules rich in polyunsaturated fatty acids to maintain membrane stability and regulate signal transduction. A deeper understanding of the lipid metabolic stress response mechanisms of Symbiodiniaceae with different environmental sensitivities under heat stress provides new insights into enhancing coral adaptability to environmental changes from a symbiotic partner perspective.更多还原