CHARACTERIZATION OF CYANOPHAGES ISOLATED FROM FRESHWATER BODIES IN KYIV REGION, UKRAINE

Background. Cyanophages, which specifically infect cyanobacteria, are among the most ecologically significant bacteriophages in aquatic ecosystems. These viruses typically possess icosahedral capsids containing double-stranded DNA and have tails that vary in length and morphology depending on the cyanophage species. This study aims to characterize cyanophages and describe their morphological and molecular features based on virus isolates obtained from freshwater bodies in the Kyiv region between July and September 2024. Methods. Cyanophage isolation and concentration, transmission electron microscopy (TEM), polymerase chain reaction (PCR), gel electrophoresis and sequencing. Results. The primary isolation and identification of cyanophages from freshwater bodies in the Kyiv region were carried out. Electron microscopy revealed podo- and myovirus-like phage particles of varying sizes and morphological characteristics, suggesting their affiliation with the class Caudoviricetes. A PCR product of the expected size was successfully obtained using CPS1-CPS4 primers, which target the portal protein gene, amplifying a fragment of the gp20 gene from three isolates. Molecular analysis using PCR targeting the gp20 gene provided genetic evidence supporting the cyanophage identity of the isolates. A BLASTn search against the NCBI GenBank database revealed that the sequenced amplicon has the highest similarity (80.48 % and 80.14% identity) with fragments of the gp20 gene from uncultivated cyanophages (accession numbers KY082133.1 and MT596572.1). Conclusions. These findings represent the first molecular investigation of cyanophages in Ukraine, expanding current knowledge of the morphological diversity and genetic characteristics of freshwater cyanophages. TEM analysis confirmed the presence of tailed virions with podo and myovirus-like morphology, consistent with representatives of the class Caudoviricetes. The amplicons obtained from the gp 20 gene fragment isolates in this study are related to previously reported T4-like cyanophages, while also representing distinct lineages within this group. Furthermore, the results provide a foundation for future studies aimed at characterizing the ecological roles of these viruses and exploring their potential practical use in the biocontrol of harmful cyanobacterial blooms.