Genome sequence of the novel freshwater Microcystis cyanophage Mwe-Yong1112-1.

The freshwater cyanophage Mwe-Yong1112-1 was isolated using Microcystis wesenbergii as a host and found to have an icosahedral head, about 45 nm in diameter, and a flexible tail, approximately 133 nm in length and 4.5 nm in width. The complete genome of the cyanophage is 39,679 bp in length with a G+C content of 66.6%. Mwe-Yong1112-1 shared the highest pairwise average nucleotide identity (ANI) value of 67.7% (below the ≥95% boundary to define a species) and the highest nucleotide sequence similarity of 17.48% (below the >70% boundary to define a genus) with the most closely related phage. In a proteomic tree, Mwe-Yong1112-1 and three unclassified phages formed a monophyletic clade between the families Saparoviridae and Pyrstoviridae, but Mwe-Yong1112-1 occupied a separate branch from the other three phages, suggesting that it represents a new evolutionary lineage. This study enriches the available information about freshwater cyanophages.