Effect And Mechanism Of NaCl On The Interaction Of Halovirus QHHSV-1 And Its Host

Viruses are the most abundant biological entities on earth,and the number of virus particles can be as high as 10¹⁰in high saltwater environment.Phage is the most important group of viruses in the environment,which plays an important role in regulating the number and community structure of hosts,the biogeochemical cycle of chemical elements,and the flow of food and energy.Viruses that infect bacteria,archaea and eukaryotes living in a high-salt environment are called halovirus.The interaction between halovirus and host affects the evolution,adaptation and ecological characteristics of virus and host.Salinity is the most important abiotic factor affecting the interaction between halovirus and host.However,at present,there is a lack of research on the effect of salinity on virus-host interaction and its mechanism.The exploration of this problem will help to understand the infection mechanism and ecological function of halovirus.In this paper,we made a preliminary study on the response and mechanism of halovirus QHHSV-1 to Na Cl concentration in the interaction between halovirus and host.In this paper,firstly,the effect of Na Cl concentration on the relationship between virus QHHSV-1 and its host Halomonas ventosae QH52-2 was studied,and then the effects of ion types(K⁺,Mg²⁺,Na⁺),ion concentration and osmotic pressure on the interaction between QHHSV-1 and QH52-2 were discussed.Finally,RNA-Seq was used to analyze the changes of virus and host gene transcription after halovirus infected host.The main conclusions are showed as follows:(1)Latent period,lytic period and burst size of virus QHHSV-1 were influenced by Na Cl concentration.The burst size of QHHSV-1 was highest at 5%Na Cl concentration,followed by 2%,8%and 15%,but the virus wasn't proliferated at 20%Na Cl concentration.(2)The adsorption efficiency of QHHSV-1 was affected by the physiological status of the host cells and the Na Cl concentration of adsorption,but the adsorption rate of viruses at different concentrations of Na Cl was higher than 80%,indicating that the decrease of adsorption rate was not the main reason why QHHSV-1 did not proliferate at 20%of Na Cl concentration.(3)Part of the reason QHHSV-1 did not proliferate at 20%Na Cl concentration is that DNA is not successfully injected into the host cell.(4)The lysogenicity of QHHSV-1 was also influenced by Na Cl concentration.When the Na Cl concentration is 20%,the virus lysis rate was the lowest and the lysogenic rate was the highest,which was 4.37±0.49%.Thus,the inhibition of QHHSV-1 proliferation at 20%Na Cl concentration is due in part to viral lysogen production.(5)Na⁺was a necessary factor for the adsorption and proliferation of QHHSV-1.The osmotic pressure formed by PEG8000 cannot support the infection and proliferation of QHHSV-1 on QH52-2.(6)Transcriptome analysis showed that viral QHHSV-1 infection resulted in significantly different expression of QH52-2 gene in the host at different Na Cl concentrations.The QHHSV-1 gene was also temporal expression.In conclusion,the interaction between halovirus QHHSV-1 and its host and its mechanism at different salinity levels are reported in this paper.These results will provide important information on the virus-host relationship in extremely high-salinity environments,and will play a positive role in further understanding the ecological function of salt virus and host in high-salinity environments.