代谢物质在深海噬菌体与宿主菌相互作用过程中的作用机理研究

In deep-sea environments, bacteriophages interact with their hosts extensively. They have a significant impact on the food chain and biological matter cycle of deep-sea ecosystems by interacting with bacterial hosts. So far, considerable advances have been made in revealing the proteinic interactions between deep-sea bacteriophages and hosts, however, to our best knowledge, little is known about the role of metabolites in bacteriophage-host interactions. Thus, in our study the role of metabolites in bacteriophage-host interactions will be investigated in depth. In our previous studies, GVE2, a thermophilic bacteriophages isolated from the deep-sea hydrothermal vent in the east Pacific Ocean, had been extensively investigated on its interaction with Geobacillus sp. E263. A total of 24 metabolites were found to be significantly up-regulated or down-regulated during GVE2-host interaction. In this project, the role of phage-associated metabolites in the phage-host interactions as well as its action mechanism will be studied, which will help to elucidate the comprehensive effect of bacteriophages on the biosphere in deep-sea ecosystem.

深海环境中噬菌体与宿主菌的相互作用十分活跃，噬菌体通过这种相互作用对海洋生态系统的食物链和物质循环发挥重要影响。虽然有越来越多的研究关注于深海噬菌体与宿主菌之间的蛋白互作，但是到目前为止国内外对噬菌体与宿主在代谢水平的相互作用却知之甚少，因此本项目拟在代谢水平上对代谢物质在深海噬菌体与宿主菌互作过程中的作用展开研究。在前期的工作中, 我们对一株分离自东太平洋深海热液口的嗜热噬菌体GVE2与其宿主菌Geobacillus sp. E263的相互作用开展了大量研究, 并筛选到了24种在噬菌体感染后显著上调或下调的宿主代谢物。在本项目中，我们重点研究这些噬菌体感染相关代谢物质对噬菌体侵染、裂解宿主的影响，并选择活性代谢物质进一步研究其发挥作用的具体通路，由此来揭示深海噬菌体与宿主在代谢水平的相互作用，为全面探索噬菌体在深海生态系统中的生态功能提供重要依据。

深海环境中噬菌体与宿主菌的相互作用十分活跃，噬菌体通过这种相互作用对海洋生态系统的食物链和物质循环发挥重要影响。虽然有越来越多的研究关注于深海噬菌体与宿主菌之间的蛋白互作，但是到目前为止国内外对噬菌体与宿主在代谢水平的相互作用却了解较少。本项目以一株分离自东太平洋深海热液口的嗜热噬菌体GVE2与其宿主菌Geobacillus sp. E263为实验对象，通过LC-MS方法对感染和未感染GVE2的宿主代谢物进行代谢组学分析，共获得了118种GVE2感染相关代谢物质，并对其中15种代谢物进行了二级质谱精确鉴定。KEGG通路分析表明GVE2感染相关代谢物主要参与磷酸戊糖通路、精氨酸和脯氨酸代谢、维生素B6代谢、嘧啶和嘌呤代谢，表明GVE2感染会引起宿主代谢通路的显著变化。选取二级质谱精确鉴定的GVE2感染后上调的代谢物腺嘌呤和尿苷二磷酸进一步研究其对噬菌体DNA复制的影响。荧光定量PCR结果发现高浓度的尿苷二磷酸和腺嘌呤都可以显著提高GVE2的基因组拷贝数，且腺嘌呤促进噬菌体DNA复制的效果更为明显。我们推测这两种代谢物可能是作为GVE2 DNA复制的原料或能量来源从而促进GVE2的增殖。本项目有助于揭示深海噬菌体与宿主在代谢水平的相互作用，为全面探索噬菌体在深海生态系统中的生态功能提供重要依据。