裂解或溶源-细菌遭遇噬菌体后的命运抉择

Lysis or lysogen: the fate decision when bacteria encounter phages

摘要:

噬菌体是地球上数量最丰富的有机体，其在自然生态系统的塑造和细菌进化驱动中发挥着至关重要的作用。在与宿主的相互斗争中，噬菌体可以选择以下2种方式决定其与宿主的命运：（1）裂解：通过裂解宿主细胞最终大量释放噬菌体颗粒；（2）溶源：将其染色体整合到宿主细胞基因组中，与宿主建立一种潜在的互存关系。对于一些温和的噬菌体，这种倾向进一步受到感染多样性的调节，其中单一感染主要是裂解性的，而多重感染则多是溶源性的。溶源性的噬菌体不仅可以根据外界环境的理化因子，还可以通过细菌自身的群体感应系统来启动裂解-溶源开关，进而决定其宿主菌的命运。与此同时，宿主细菌在与噬菌体长时间的斗争中也进化出了针对噬菌体的手段。总而言之，噬菌体深刻影响着细菌的群落动态、基因组进化和生态系统等，而这一切都取决于噬菌体与宿主间的斗争模式（裂解/溶源性感染）。本文探讨了导致温和噬菌体对宿主菌进行裂解-溶源命运抉择的影响因素并系统性总结了细菌在面对噬菌体侵染时的应对策略的最新研究进展，以期能为噬菌体与宿主的研究提供建议和帮助。

关键词:噬菌体;裂解-溶源;细菌宿主;群体感应;进化

Abstract:

Phage, the most abundant organisms on the earth, play a vital role in the shaping of natural ecosystems and the driving of bacterial evolution. In the struggle with the host, phage can choose the following two ways to determine fate of itself and the host:(1) Lysis:lysing the host cell, and finally releasing a large amount of phage particles; (2) Lysogen:integrating its chromosome into the host cell, then establishing a potential coexistence relationship with the host. For some temperate phages, this tendency is further regulated by the diversity of infections, where single infections are mainly lytic, while multiple infections are mostly lysogenic. Lysogenic phage can not only activate the lysis-lysogen switch based on the physical and chemical factors of the external environment, but also use the bacteria's own quorum sensing system to initiate the lysis-lysogen switch, and then determine the fate of its host bacteria. Meanwhile, the host bacteria have evolved means to target phage during the long-term struggle. In general, phage profoundly affects bacterial community dynamics, genome evolution, and ecosystems, etc., and all of this depends on the mode of struggle between phages and host (lysis/lysogenic infection). This paper discusses the influencing factors that cause temperate phage to lyse the host bacteria-lysogenic fate, and systematically summarizes the latest research on coping strategies of bacteria facing phage infection, hoping to provide help and suggestions for the follow-up study on the interaction between phage and host.

Key words:phage;lysis-lysogen;bacterial host;quorum sensing;evolution