Seasonal variations in cyanophage communities in the coastal waters of Kuwait

Cyanobacteria and the viruses that infect them (cyanophages) are crucial to the marine ecosystem, but little is known regarding the genetic diversity of natural cyanophages and their variation over space and time in Kuwait waters. In this study, we explored the seasonal diversity of cyanophages specifically the cyanomyophages in the coastal waters of Kuwait using denaturing gradient gel electrophoresis (DGGE) and cloning sequencing by tar-geting the portal protein-encoding gene g20. Surface-and deep-water samples were collected bimonthly from three coastal sites over a period of 14 months.The DGGE bands for both the surface-and deep-water samples revealed a dramatic seasonal variation in cyanomyophages across all sites but with no spatial variations. The bands exhibited a similar pattern in the warmer season (June to October), with very intense bands observed specifically for the samples collected in August and October compared to those collected in winter-spring (January to April). Furthermore, g20 clone li-braries prepared from single-month samples provided evidence of depth-related differences in cyanomyophage communities. Phylogenetic analysis indicated that the most abundant g20 operational taxonomic units (OTUs) clustered with the ubiquitous culture-containing cyanomyophage marine cluster II. In addition, the obtained OTUs were closely related to cyanophages infecting Synechococcus and Prochlorococcus hosts. This study demonstrated the seasonal diversity of cyanophages in the coastal waters of Kuwait, and the diversity appeared to be greater in deep water. This highlights the need for further studies to determine whether these temporal changes in cyanophage community abundance and diversity reflect recurring annual patterns.