Lu Longfei, Huang Xingyu, Zheng Pengfei, Wei Shuzhen, Jiao Nianzhi, Zhang Rui, Li Xuejing, Yang Yunlan
Key Laboratory of Tropical Marine Ecosystem and Bioresource, Fourth Institute of Oceanography, Ministry of Natural Resources, Beihai, China.
Carbon Neutral Innovation Research Center, State Key Laboratory of Marine Environmental Science, Fujian Key Laboratory of Marine Carbon Sequestration, College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.
Front Microbiol. 2025 Jun 10;16:1592355. doi: 10.3389/fmicb.2025.1592355. eCollection 2025.
, an aerobic anoxygenic photoheterotrophic bacterial genus, plays a vital role in carbon and energy cycling in marine environments. However, their phage predators remain poorly understood, with only two strains previously reported. This study isolated and characterized a novel phage, vB_EauS-R34L1 (R34L1), and its sub-strain vB_EauS-R34L2 (R34L2), from coastal seawater. Both phages exhibit long-tailed, icosahedral morphologies and relatively narrow but slightly different host ranges. One-step growth curve analysis revealed a 160-min latent period and burst sizes of 81 and 91 PFU/cell for R34L1 and R34L2, respectively. Genomic analysis showed that the phages possess dsDNA genomes of 56,415 bp (R34L1) and 54,924 bp (R34L2), with G + C contents of 61.60 and 61.19%, respectively. Both phages harbor a suite of unique genes, including GapR and GH19, which are crucial for host interaction and ecological functionality. Blastn analysis indicated a 99.73% genome similarity between them. Taxonomic and phylogenetic analyses positioned them in a novel viral genus cluster, , under the family , indicating a distant evolutionary relationship with known phages. Metagenomic queries suggested that R34L1- and R34L2-like phages are exclusively abundant in temperate and tropical epipelagic zones. This study expands our understanding of phages and provides insights into their ecological roles in marine ecosystems.
[该属为需氧不产氧光合异养细菌属]，在海洋环境的碳和能量循环中起着至关重要的作用。然而，它们的噬菌体捕食者仍知之甚少，此前仅报道了两个菌株。本研究从沿海海水中分离并鉴定了一种新型噬菌体vB_EauS-R34L1（R34L1）及其亚菌株vB_EauS-R34L2（R34L2）。两种噬菌体均呈现长尾二十面体形态，宿主范围相对较窄但略有不同。一步生长曲线分析显示，R34L1和R34L2的潜伏期均为160分钟，爆发量分别为81和91 PFU/细胞。基因组分析表明，这两种噬菌体拥有双链DNA基因组，大小分别为56,415 bp（R34L1）和54,924 bp（R34L2），G+C含量分别为61.60%和61.19%。两种噬菌体都含有一系列独特的基因，包括对宿主相互作用和生态功能至关重要的GapR和GH19。Blastn分析表明它们之间的基因组相似度为99.73%。分类学和系统发育分析将它们定位在[某科下的一个新型病毒属簇]中，表明与已知噬菌体的进化关系较远。宏基因组查询表明，类似R34L1和R34L2的噬菌体仅在温带和热带上层带大量存在。本研究扩展了我们对[该属噬菌体]的理解，并为它们在海洋生态系统中的生态作用提供了见解。
