Genomic Analysis And Quantitative Proteomics Analysis Of The Cyanophage MinS1 And YongM

Eutrophication of water bodies is a global water pollution problem that leads to cyanobacterial blooms.The blooming growth of cyanobacteria tends to cause cyanobacterial blooms in lakes,of which Microcystis and Nostoc sp are the most prevalent bloom-forming cyanobacteria in freshwater ecosystems,and this has become a common phenomenon in fresh water bodies worldwide.Cyanobacteria bloom waters are characterized by their high chemical diversity of non-ribosomal peptides(NRPs),including the hepatotoxin nodularin(NOD)and cyanotoxins,which not only cause toxic effects on aquatic organisms,but also negatively affect human health and ecosystem function.Cyanophage,a virus that infects cyanobacteria,can play a major role in the dynamics,structure,and genetic diversity of cyanobacterial communities and is a harmless biological control agent for cyanobacterial blooms,offering new possibilities for the biological prevention and management of cyanobacteria outbreaks.Compared to the marine phages that have been extensively studied,there is still very limited research related to freshwater cyanophages.Moreover,most of the reported cyanophages have host specificity,narrow algaecide spectrum and long lysis cycle,while water blooms are usually formed by mixed outbreaks of multiple cyanobacteria,so their application against water blooms is limited.Therefore,screening for efficient cyanophages with a wide range of hosts and studying their characteristics and infestation mechanisms are particularly important for the management of water blooms,as well as for the future protection and prevention of the water environment.In this study,a novel broad-spectrum lytic Microcystis aeruginosa cyanophage,Min S1,was isolated using Microcystis aeruginosa cyanobacteria FACHB-905 as the host cyanobacteria.The cyanophage Min S1 genome consists of a double-stranded 49966 bp DNA molecule containing an icosahedral head approximately 54 nm in diameter and a 260 nm long non-contractile tail.The Min S1 genome was analyzed with Megablast and revealed it had very low homology with known phages in the NCBI database(only 1% of the genome showed weak homology with known phages).The Min S1 contained 75 ORFs,of which23 ORFs were predicted to proteins of known function,39 ORFs of unknown function,and 13 ORFs showed no similarity to any protein sequences.Phylogenetic analysis and transmission electron microscopy morphological observations indicated that Min S1 belongs to the Siphoviridae family.Various experiments had confirmed that the cyanophage can infect several different orders of cyanobacteria,including Chroococcales,Nostocales,Oscillatoriale,Hormogonales,and Synechococcales,indicating it has a very broad host range.In addition,Min S1 has no antibiotic tolerance genes,t RNAs virulence genes,and is tolerant to p H,temperature,salinity,UV,and metal ions,suggesting that Min S1 has good potential for application as a biocontrol agent against cyanobacterial blooms.Nostoc cyanophage Yong M(Yong M)is a novel cyanophage isolated from Dianchi water samples with Nostoc sp FACHB-596 strain as the host,which has high killing efficiency against its host.However,the protein changes of the cyanophage during the process of infestation and killing the host remain unknown.In order to characterize the proteins and their regulatory networks of host cyanobacteria lysed by Yong M and to assess whether this strain of cyanophage Yong M can be used as a potent sump virus for further treatment of cyanobacterial blooms,a label-free high-throughput quantitative proteomics and bioinformatics approach was applied for the first time to analyze the differentially expressed proteins(DEPs)of the strongly lysed novel cyanophage Yong M infested host FACHB-596 strain after 1 h and 8 h of infestation.Metabolic pathways such as photosynthesis,photosynthesis-antennal proteins,oxidative phosphorylation,ribosomes,carbon fixation,and glycolysis/gluconeogenesis were found to be significantly altered in infected hosts,while differentially expressed proteins were associated with metabolic processes such as photosynthesis,precursor metabolites,energy production,and organic nitrogen compounds.In further,the key proteins involved in Yong M-host interactions in these DEPs are Photosystem I P700 chlorophyll a apoprotein,Carbon dioxide concentrating mechanism protein,Cytochrome b and some Yong M-infestation lysis-related enzymes,which may serve as hotspots for the study of Yong M-host interactions.This study expands the knowledge related to the diversity and biological characteristics of cyanophages and provides new information on the interaction between cyanophage and host cyanobacteria at the proteomic level,which may shed light on the future design and manipulation of artificial super cyanophages against cyanobacterial blooms.