Marine picocyanobacteria (Synechococcus and Prochlorococcus) are major contributors to global primary productivity. Their main viruses are myoviruses and podoviruses, but their quantification and interaction with cyanobacteria have rarely been studied. Based on the 16S-23S rRNA gene of marine picocyanobacteria, the nrdA gene of marine myoviruses, and the RNAP gene of podoviruses, we conducted quantitative PCR and genetic diversity analysis of cyanobacteria and their viruses within 200m of the South China Sea, identifying the composition and abundance of picocyanobacteria and their viral communities. It was found that cyanomyoviruses and cyanomyoviruses in the South China Sea have different adaptation strategies to deep water environments: deep myoviruses may increase latent periods and viral attachment rates; whereas podoviruses may increase the number of offspring or shorten latent periods to enhance population abundance. Additionally, we found significant differences between intracellular and extracellular viral communities of cyanobacteria, with podoviruses showing greater differences than myoviruses. Correlation clustering analysis revealed that myoviruses and podoviruses mainly fall into three categories: (1) high-light types primarily infecting Prochlorococcus HLII (2) intermediate-transitional types mainly infecting Prochlorococcus HLII and HLVI (3) types primarily infecting low-light Prochlorococcus, indicating a synergistic distribution characteristic between cyanophages and cyanobacteria. Phages with cross-module capabilities do not interact with cyanobacteria as strongly as those within specific modules, but the cost may involve reduced interactions with cyanobacteria within their own module. The results of VPA analysis emphasized the importance of cyanobacteria to the viral community, with a significantly higher explanation for the myovirus community than the podovirus community. Our work reveals the abundance and community distribution structure of cyanobacteria and viruses in the South China Sea region and provides important information for future assessments of the ecological role of virus-host interactions.

 

Picocyanobacteria,Relationship,Cyanopages