珊瑚共生细菌稳定性调节机制研究进展

Rresearch progress on the homeostasis adjustment mechanisms of coral symbiotic bacteria

珊瑚礁卓越的生态价值得益于共生系统的稳定与健康,而"珊瑚-微生物"共生体的平衡是维护珊瑚礁生态系统健康的重要基石.过去10年里针对共生体的稳定性调节机制进行了大量研究,取得了一些重要成果,并建立了"微生物-宿主-环境"三者之间的关系;但基于共生系统的复杂性,涉及的稳态调节机制复杂而多变,一些基础理论仍然有待达成共识.本文以珊瑚共生菌为重点,尝试梳理最新的研究进展,包括共生菌的组成,环境因子对共生菌群的影响,以及多重压力下(水温、光照、营养盐以及人类活动)的稳态调节类型,重点包括光合作用下的碳浓缩机制,时空异质性的微生物选择偏好、共生体的营养分配,以及群体感应信号介导下的调节过程等.最后从组学角度总结了稳态调节过程涉及的分子机制,如pH稳态钙化、能量代谢差异、氧化应激以及细胞色素P450家族基因的应答等.对今后的研究重点和可能方向也进行了提炼,包括研究维度的扩充(关注古菌)、新技术-新方法("拉曼光谱-组学-Nano时间飞行质谱"耦合)的应用以及生态模型的构建等.本综述旨在提升对珊瑚、细菌和环境之间互作关系的认识,增进对共生体微生态学机制的理解,可为珊瑚礁的生态健康和资源保护提供理论借鉴.(图2参117)

The excellent ecological value of coral reefs results from the stability and health of the symbiotic system,and the balance and stability of the"coral-bacteria"holobiont is an important cornerstone of healthy coral reefs.The regulation mechanisms of holobiont have been thoroughly investigated over the past decade,and important insights into the relationships among the"microorganism-host-environment"have been reported.However,the symbiotic system is complex,so the steady-state adjustment mechanisms of holobiont are not one-dimensional.Under multiple environmental pressures,the ecological behavior of holobiont is complex and variable,some basic theories lack a general consensus.In this review,we summarize the latest research progress,including the composition of the symbiotic microorganisms,the influence of the environmental factors on the coral-associated bacteria,and the steady-state regulation types under multiple pressures(e.g.,increased pollution,rising water temperature,and increased human activity).The main contents include the carbonconcentrated mechanisms,host preference for their associated bacteria,nutrition regulation,and homeostasis adjustment mechanisms of the coral symbiotic bacteria under quorum sensing.Also,the molecular mechanisms of coral holobiont homeostasis,such as pH steady-state calcification,energy metabolism,oxidative stress,and the response of the cytochrome P450 family genes,are summarized.Finally,we define the research issues and possible future directions,including additional archaeal research in coral holobiont using new methods(e.g.,Raman spectroscopy coupled with"omics"or nano time-of-flight mass spectrometry)and the construction of ecological models.This review sought to improve our understanding of the interactions among corals,microorganisms,and the environment.The information presented here allows a better understanding of the microecological mechanisms of symbiosis and provides a theoretical reference for coral reef protection.