Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.
Department of Biology, San Diego State University, San Diego, California, USA.
mSystems. 2024 May 16;9(5):e0008324. doi: 10.1128/msystems.00083-24. Epub 2024 Apr 22.
Algal blooms can give snowmelt a red color, reducing snow albedo and creating a runaway effect that accelerates snow melting. The occurrence of red snow is predicted to grow in polar and subpolar regions with increasing global temperatures. We hypothesize that these algal blooms affect virus-bacteria interactions in snow, with potential effects on snowmelt dynamics. A genomic analysis of double-stranded DNA virus communities in red and white snow from the Whistler region of British Columbia, Canada, identified 792 putative viruses infecting bacteria. The most abundant putative snow viruses displayed low genomic similarity with known viruses. We recovered the complete circular genomes of nine putative viruses, two of which were classified as temperate. Putative snow viruses encoded genes involved in energy metabolisms, such as NAD synthesis and salvage pathways. In model phages, these genes facilitate increased viral particle production and lysis rates. The frequency of temperate phages was positively correlated with microbial abundance in the snow samples. These results suggest the increased frequency of temperate virus-bacteria interactions as microbial densities increase during snowmelt. We propose that this virus-bacteria dynamic may facilitate the red snow algae growth stimulated by bacteria.IMPORTANCEMicrobial communities in red snow algal blooms contribute to intensifying snowmelt rates. The role of viruses in snow during this environmental shift, however, has yet to be elucidated. Here, we characterize novel viruses extracted from snow viral metagenomes and define the functional capacities of snow viruses in both white and red snow. These results are contextualized using the composition and functions observed in the bacterial communities from the same snow samples. Together, these data demonstrate the energy metabolism performed by viruses and bacteria in a snow algal bloom, as well as expand the overall knowledge of viral genomes in extreme environments.
藻华会使融雪呈现红色，降低雪的反照率，并产生一种加速融雪的失控效应。随着全球气温的升高，预测极地和亚极地地区的红雪现象将会增加。我们假设这些藻华会影响雪中的病毒-细菌相互作用，从而对融雪动态产生潜在影响。对来自加拿大不列颠哥伦比亚省惠斯勒地区的红白雪中双链 DNA 病毒群落进行的基因组分析，鉴定出 792 种感染细菌的假定病毒。最丰富的假定雪病毒与已知病毒的基因组相似度较低。我们回收了 9 种假定病毒的完整圆形基因组，其中两种被归类为温和型。假定的雪病毒编码与能量代谢相关的基因，如 NAD 合成和回收途径。在模型噬菌体中，这些基因促进了病毒粒子的大量产生和裂解率的提高。温和噬菌体的频率与雪样本中微生物丰度呈正相关。这些结果表明，随着融雪过程中微生物密度的增加，温和型病毒-细菌相互作用的频率增加。我们提出，这种病毒-细菌动态可能促进了受细菌刺激的红雪藻生长。
红雪藻中的微生物群落加剧了融雪速率。然而，在这种环境变化中，病毒在雪中的作用尚未阐明。在这里，我们从雪病毒宏基因组中提取了新的病毒，并定义了在白雪和红雪中雪病毒的功能能力。这些结果使用来自相同雪样本的细菌群落的组成和功能进行了上下文分析。这些数据共同证明了在雪藻中病毒和细菌进行的能量代谢，以及扩展了在极端环境中病毒基因组的整体知识。
