The effect of a temperature‐sensitive prophage on the evolution of virulence in an opportunistic bacterial pathogen

Viruses are key actors of ecosystems and have major impacts on global biogeochemical cycles. Prophages deserve particular attention as they are ubiquitous in bacterial genomes and can enter a lytic cycle when triggered by environmental conditions. We explored how temperature affects the interactions between prophages and other biological levels by using an opportunistic pathogen, the bacterium Serratia marcescens, that harbours several prophages and that had undergone an evolution experiment under several temperature regimes. We found that the release of one of the prophages was temperature-sensitive and malleable to evolutionary changes. We further discovered that the virulence of the bacterium in an insect model also evolved and was positively correlated with phage release rates. We determined through analysis of genetic and epigenetic data that changes in the bacterial outer cell wall structure possibly explain this phenomenon. We hypothezise that the temperature-dependent phage rele...病毒是生态系统中的关键参与者，对全球生物地球化学循环具有重大影响。前噬菌体（prophage）尤其值得关注：它们广泛存在于细菌基因组中，且可在环境条件触发下进入裂解周期。本研究以携带多种前噬菌体、且曾在多种温度条件下开展过进化实验的机会致病菌——粘质沙雷氏菌（Serratia marcescens）为研究对象，探究温度如何影响前噬菌体与其他生物层级间的相互作用。研究发现，其中一种前噬菌体的释放具有温度敏感性，且可随进化过程发生改变。本研究进一步发现，该细菌在昆虫模型中的毒力也发生了进化，且与噬菌体释放速率呈正相关。通过对遗传与表观遗传数据的分析，我们确定细菌外细胞壁结构的改变或许可以解释这一现象。我们提出假说：温度依赖的噬菌体释放……