A Novel Wide-Range Freshwater Cyanophage MinS1 Infecting the Harmful Cyanobacterium Microcystis aeruginosa

Abstract

Microcystis aeruginosa, as one of the major players in algal bloom, produces microcystins, which are strongly hepatotoxic, endangering human health and damaging the ecological environment. Biological control of the overgrowth of Microcystis with cyanophage has been proposed to be a promising solution for algal bloom. In this study, a novel strain of Microcystis cyanophage, MinS1, was isolated. MinS1 contains an icosahedral head approximately 54 nm in diameter and a 260 nm-long non-contractile tail. The phage genome consists of a linear, double-stranded 49,966 bp DNA molecule, which shares very low homology with known phages in the NCBI database (only 1% of the genome showed weak homology with known phages when analyzed by megablast). The phage contains 75 ORFs, of which 23 ORFs were predicted to code for proteins of known function, 39 ORFs were predicted to code for proteins of unknown function, and 13 ORFs showed no similarity to any protein sequences. Transmission electron microscopy and phylogenetic analysis showed that MinS1 belongs to the family Siphoviridae. Various experiments confirmed that the phage could infect several different orders of cyanobacteria, including Chroococcales, Nostocales, Oscillatoriales, Hormogonales, and Synechococcales, indicating that it has a very broad host range. In addition, MinS1 has no known antibiotic tolerance genes, virulence genes, and tRNAs, and it is tolerant to temperature, pH, UV, and salinity, suggesting that MinS1 has good potential for application as a biological control agent against cyanobacterial blooms. This study expands the diversity and knowledge of cyanophages, and it provides useful information for the development of novel prevention and control measures against cyanobacterial blooms.

Biological and Genomic Characteristics of MaMV-DH01, a Novel Freshwater Myoviridae Cyanophage Strain

“…This finding agrees with previous reports that four other Microcystis cyanophage strains (Ma-LMM01, MaMV-DC, PhiMa05, and Mic1) also have high host specificity ( 17 , 20 , 21 , 24 ). Conversely, other Microcystis cyanophage strains showed a wide host range, including the myoviruses Mae-Yong924-1 and MinS1 and the siphovirus Me-ZS1 ( 3 , 22 , 23 ) ( Table 2 ). These reports collectively reinforced the understanding of the specificity and complexity of cyanophage-host interactions and the diversity of the host range of Microcystis phages.…”

“…Compared to marine cyanophages, which have been widely studied, there are few reports on freshwater cyanophages and, specifically, Microcystis phages ( 15 ). To date, only 13 Microcystis cyanophages have been reported, for which only 8 genomes (those of MaMV-DC, Ma-LMM01, Ma-LBP, Mic1, Me-ZS1, PhiMa05, Mae-Yong924-1, and MinS1) have been sequenced, with genome sizes under 200 kb ( 16 – 23 ). Only six of these reported cyanophages have been isolated from M. aeruginosa : Ma-LBP, Ma-LMM01, MaMV-DC, Mic1, Mae-Yong924-1, and MinS1.…”

Novel lytic and lysogenic cyanophages predicted to infectMicrocoleusassociated with anatoxin-producing benthic mats

“…The copyright holder for this preprint this version posted April 13, 2023. ; https://doi.org/10.1101/2023.04.12.536658 doi: bioRxiv preprint Zhang et al, 2022). For example, the activity of cyanophages infecting microcystinproducing Microcystis species (Yoshida et al, 2008) can lead to a significant reduction in microcystin production (Naknaen et al, 2021).…”

Novel virulent and temperate cyanophages predicted to infect Microcoleus associated with anatoxin‐producing benthic mats

“…Through their intimate association with their hosts, phages play important roles in shaping both cell abundance and diversity in microbial communities (Bouvier & del Giorgio, 2007; Brown et al, 2019). In particular, it is well‐documented that phages infecting cyanobacteria (cyanophages) can impact the population dynamics of toxic blooms (Grasso et al, 2022; Zhang et al, 2022). For example, the activity of cyanophages infecting microcystin‐producing Microcystis species (Yoshida et al, 2008) can lead to a significant reduction in microcystin production (Naknaen et al, 2021).…”