Molecular Mechanisms of Auxiliary Metabolic Genes in Marine Viruses

Marine viruses possess auxiliary metabolic genes (AMGs) acquired through horizontal gene transfer from their hosts, enabling them to reprogram host metabolic pathways during infection. These genes significantly influence processes such as photosynthesis, nitrogen, sulfur, and carbon metabolism, lipid biosynthesis, and transport systems, thereby impacting host physiology and global biogeochemical cycles. Recent large-scale metagenomic surveys, like the Tara Oceans project, have identified thousands of AMGs across various metabolic pathways. Functional studies are beginning to reveal how AMGs modulate enzyme activity, host energy flux, and nutrient cycling in illuminated and dark oceans, sediments, oxygen minimum zones (OMZs), and under nutrient-limited conditions. However, key gaps remain in linking AMG expression to protein function and ecological impact. Future research integrating single-cell and single-virion omics, structural biology, synthetic biology, and ecological modeling is likely to illuminate both the molecular mechanisms involved and their broader ecological consequences. This understanding is crucial for comprehending the role of marine viruses in ecosystem dynamics and global nutrient cycles.