Xu Yongqian, Liang Jiayuan, Qin Liangyun, Niu Tianyi, Liang Zhuqing, Li Zhicong, Chen Biao, Zhou Jin, Yu Kefu
Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, Coral Reef Research Center of China, School of Marine Sciences, Guangxi University, Nanning, 530004, China.
Shenzhen Key Laboratory of Marine Archaea Geo-Omics, Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China.
Microb Ecol. 2025 Jan 9;87(1):169. doi: 10.1007/s00248-024-02470-4.
Coral thermal tolerance is intimately linked to their symbiotic relationships with photosynthetic microorganisms. However, the potential compensatory role of symbiotic photosynthetic bacteria in supporting Symbiodiniaceae photosynthesis under extreme summer temperatures remains largely unexplored. Here, we examined the seasonal variations in Symbiodiniaceae and photosynthetic bacterial community structures in Pavona decussata corals from Weizhou Island, Beibu Gulf, China, with particular emphasis on the role of photosynthetic bacteria under elevated temperature conditions. Our results revealed that Symbiodiniaceae density and Chlorophyll a concentration were lowest during the summer and highest in the winter. Notably, the summer bacterial community was predominately composed of the proteorhodopsin bacterium BD 1-7 _clade, alongside a significant increase in Cyanobacteria, particularly Synechococcus_CC9902 and Cyanobium_PCC-6307, which represented 61.85% and 31.48% of the total Cyanobacterial community, respectively. In vitro experiments demonstrated that Cyanobacteria significantly enhanced Symbiodiniaceae photosynthetic efficiency under high-temperature conditions. These findings suggest that the increased abundance of photosynthetic bacteria during summer may mitigate the adverse physiological effects of reduced Symbiodiniaceae density, thereby contributing to coral stability. Our study highlights a potential synergistic interaction between Symbiodiniaceae and photosynthetic bacteria, emphasizing the importance of understanding these dynamic interactions in sustaining coral resilience against environmental stress, although further research is necessary to establish their role in preventing coral bleaching.
珊瑚的热耐受性与其与光合微生物的共生关系密切相关。然而，在夏季极端温度下，共生光合细菌在支持虫黄藻光合作用方面的潜在补偿作用在很大程度上仍未得到探索。在此，我们研究了中国北部湾涠洲岛十字牡丹珊瑚中虫黄藻和光合细菌群落结构的季节变化，特别强调了光合细菌在高温条件下的作用。我们的结果显示，虫黄藻密度和叶绿素a浓度在夏季最低，在冬季最高。值得注意的是，夏季细菌群落主要由视紫红质细菌BD 1-7进化枝组成，同时蓝细菌显著增加，尤其是聚球藻_CC9902和蓝藻_PCC-6307，分别占蓝细菌群落总数的61.85%和31.48%。体外实验表明，蓝细菌在高温条件下显著提高了虫黄藻的光合效率。这些发现表明，夏季光合细菌丰度的增加可能减轻虫黄藻密度降低带来的不利生理影响，从而有助于珊瑚的稳定性。我们的研究突出了虫黄藻与光合细菌之间潜在的协同相互作用，强调了理解这些动态相互作用对于维持珊瑚抵御环境压力的恢复力的重要性，尽管还需要进一步研究来确定它们在防止珊瑚白化中的作用。
