Hussain Sarfraz, Wang Xiaomeng, Pan Cong, Chen Songze, Xie Jiajia, Mahtab Nazia, Hou Shengwei, Li Shuangfei
Shenzhen Key Laboratory of Marine Bioresource & Eco-environmental Sciences, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China.
College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, China.
Appl Environ Microbiol. 2025 Jul 23;91(7):e0040725. doi: 10.1128/aem.00407-25. Epub 2025 Jul 2.
Estuarine viral communities play a key role in microbial dynamics and ecosystem functioning. However, how viruses adapt to the highly dynamic estuarine environments remains largely underexplored. This study uses viromic sequencing to investigate the DNA viruses in estuarine water samples adjacent to the Shenzhen coast. Samples were divided into two major groups based on variations in quantified water parameters, corresponding to low-salinity and high-salinity waters. A total of 16,497 viral operational taxonomic units (vOTUs) were recovered, of which 85.59% were identified as novel viruses. β-diversity of viral communities supported the partition of samples based on salinity, and viral α-diversity differed significantly between low and high salinity. Taxonomically, Caudoviricetes dominated across all sites, with Myoviridae and Podoviridae more abundant in low salinity sites and Siphoviridae and Baculoviridae more abundant in high salinity sites. Gammaproteobacteria and Bacteroidota were the dominant host taxa, with distinct shifts in host abundance across the salinity gradient. Functional analysis revealed the abundant auxiliary metabolic genes involved in lipid, nucleotide, cofactor, and polysaccharide metabolisms. In particular, the alginate-degrading polysaccharide lyase family 6 was particularly abundant at high salinity sites. These results suggested that environmental factors, particularly salinity, shape the genomic diversity of estuarine viruses, which may further impact the biogeochemical processes in estuarine ecosystems.IMPORTANCEEstuaries are highly dynamic ecosystems with strong environmental fluctuations, particularly in salinity and nutrients. This study highlights how environmental factors shape viral diversity and function by examining viral populations across the salinity gradient, providing new insights into viral dynamics in these ecosystems. We identified novel viruses and viral-encoded auxiliary metabolic genes in estuarine samples, including the discovery of a previously unreported viral alginate lyase gene that was abundant at high salinity sites, which sheds light on the ecological role of viruses in nutrient cycling and ecosystem partition. In addition, the study provides valuable information on distinct viral populations and virus-host interactions across the salinity gradient, which are essential for predicting ecosystem responses to salinity changes. These findings provide important implications for a broader understanding of microbial and viral ecology in estuarine ecosystems.
河口病毒群落在微生物动态和生态系统功能中起着关键作用。然而，病毒如何适应高度动态的河口环境在很大程度上仍未得到充分探索。本研究采用病毒组测序技术，对深圳海岸附近河口水样中的DNA病毒进行了调查。根据定量水参数的变化，将样本分为两个主要组，分别对应低盐度水和高盐度水。共获得16497个病毒操作分类单元（vOTU），其中85.59%被鉴定为新型病毒。病毒群落的β多样性支持了基于盐度的样本划分，并且病毒α多样性在低盐度和高盐度之间存在显著差异。在分类学上，有尾噬菌体目在所有位点中占主导地位，其中肌尾噬菌体科和短尾噬菌体科在低盐度位点更为丰富，而长尾噬菌体科和杆状病毒科在高盐度位点更为丰富。γ-变形菌纲和拟杆菌门是主要的宿主分类群，宿主丰度在盐度梯度上有明显变化。功能分析揭示了参与脂质、核苷酸、辅因子和多糖代谢的丰富辅助代谢基因。特别是，藻酸盐降解多糖裂解酶家族6在高盐度位点特别丰富。这些结果表明，环境因素，特别是盐度，塑造了河口病毒的基因组多样性，这可能进一步影响河口生态系统中的生物地球化学过程。
河口是高度动态的生态系统，环境波动强烈，特别是在盐度和营养物质方面。本研究通过研究盐度梯度上的病毒种群，突出了环境因素如何塑造病毒多样性和功能，为这些生态系统中的病毒动态提供了新的见解。我们在河口样本中鉴定出新型病毒和病毒编码的辅助代谢基因，包括发现了一个以前未报道的病毒藻酸盐裂解酶基因，该基因在高盐度位点丰富，这揭示了病毒在营养循环和生态系统划分中的生态作用。此外，该研究提供了关于盐度梯度上不同病毒种群和病毒-宿主相互作用的有价值信息，这对于预测生态系统对盐度变化的反应至关重要。这些发现对于更广泛地理解河口生态系统中的微生物和病毒生态学具有重要意义。
