Cyanophage thioredoxin and virulence enhancer genes differentially contribute to phage fitness and infection of marine Synechococcus

Cyanophage-encoded thioredoxin and virulence enhancer genes significantly boost phage fitness and infection success in marine Synechococcus, with thioredoxin increasing replication and cve enhancing virulence.

• Why it matters: Understanding the functional roles of viral auxiliary genes is crucial for revealing how viruses influence marine microbial populations and biogeochemical cycles, yet their significance remains largely unclear.
• What they did: The study analyzed the distribution of thioredoxin and cve genes across diverse cyanophages, then used gene deletion experiments in a marine cyanophage to assess their effects on infection dynamics and host physiology.
• The result: Thioredoxin enhances phage replication and negatively impacts host growth, while cve increases virulence and overall fitness despite reducing progeny, highlighting their roles in viral adaptation and oceanic microbial mortality.