A Seasonal variations in cyanophage communities in the coastal waters of Kuwait
Considerable scientific research has shown that cyanobacteria and the viruses that infect them (cyanophages) are exposed to seasonal variations in the marine environment. In this study, we explored the seasonal diversity of cyanophages, specifically cyanomyophages, in the coastal waters of Kuwait. Surface- and deep-water samples were collected from three coastal sites once every two months, over a period of 14 months. The cyanophage structural gene g20 was used to investigate cyanophage richness and diversity. Amplicons of the g20 gene were analyzed using denaturing gradient gel electrophoresis (DGGE), and subsequently g20 gene clone libraries were constructed and sequenced. The DGGE bands for both the Surface- and deep-water samples revealed a dramatic seasonal variation in cyanophages at all sites, 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, as compared to those collected in winter-spring (January to April). Furthermore, g20 clone libraries prepared from one-month samples provided evidence of depth-related differences in cyanophage communities. Phylogenetic analysis indicated that the most abundant g20 operational taxonomic units (OTUs) clustered with the ubiquitous marine cluster II. In addition, the majority of the OTUs obtained were similar to those of cyanophages isolated from 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. It also suggests the need for further studies to determine whether these temporal changes in cyanophage community abundance and diversity reflect recurring annual patterns.