Bailey Shaun, Clokie Martha R J, Millard Andrew, Mann Nicholas H
Department of Biological Science, University of Warwick, Coventry CV4 7AL, UK.
Res Microbiol. 2004 Nov;155(9):720-5. doi: 10.1016/j.resmic.2004.06.002.
Members of two cyanobacterial genera, Synechococcus and Prochlorococcus, are dominant within the prokaryotic component of the picophytoplankton and contribute significantly to global photosynthetic productivity. These organisms are known to be susceptible to infection by bacteriophages (viruses that infect bacteria) and it is believed that phage infection in the oceans has exerted selective pressures on the evolution of both phage and host and continues to influence community structure. Understanding of the processes of host-phage interaction within the marine environment is limited; however, new insights have arisen from sequence analysis of the genome of the bacteriophage S-PM2, which infects Synechococcus strains. The phage was found to encode homologs of the key photosystem II reaction center core polypeptides, D1 and D2. These reaction center polypeptides are known to be rapidly turned over in uninfected cells in a repair cycle that helps to protect oxygenic phototrophs against photoinhibition. This finding suggests that bacteriophages infecting marine cyanobacteria may play an active role in protecting their hosts against photoinhibition, thereby ensuring an energy supply for replication by preventing the deleterious effects on host cell integrity seen during acute photoinhibition.
蓝藻细菌的两个属，即聚球藻属和原绿球藻属，在微微型浮游植物的原核生物组成部分中占主导地位，并对全球光合生产力有显著贡献。已知这些生物易受噬菌体（感染细菌的病毒）感染，并且人们认为海洋中的噬菌体感染对噬菌体和宿主的进化都施加了选择压力，并继续影响群落结构。对海洋环境中宿主 - 噬菌体相互作用过程的了解有限；然而，通过对感染聚球藻菌株的噬菌体S - PM2基因组的序列分析有了新的见解。发现该噬菌体编码关键光系统II反应中心核心多肽D1和D2的同源物。已知这些反应中心多肽在未感染的细胞中通过一个有助于保护产氧光合生物免受光抑制的修复循环而快速周转。这一发现表明，感染海洋蓝藻细菌的噬菌体可能在保护其宿主免受光抑制方面发挥积极作用，从而通过防止急性光抑制期间对宿主细胞完整性的有害影响来确保复制的能量供应。
