Project description:Whole-genome expression dynamics of cyanopodovirus P-SSP7 and its host Prochlorococcus strain MED4 have been reported. To investigate whether cyanopodoviruses infecting Prochlorococcus and Synechococcus have similar transcription strategy and host response to phage infection, genomic and transcriptomic analyses were conducted on cyanopodovirus S-SBP1 that infects Synechococcus strain WH7803. S-SBP1 has a latent period of 8 h and a burst size of 30 progeny phages per cell. S-SBP1 was most similar to cyanopodovirus S-RIP2 that also infects Synechococcus WH7803, in terms of whole genome phylogenetic relationship and average nucleotide identity (ANI). Three hypervariable genomic islands were found when comparing the genomes of S-SBP1 and S-RIP2, and single nucleotide variants (SNV) were observed on three genes of S-SBP1, which are located within the island regions. Based on RNA-seq analysis, genes of S-SBP1 were clustered into three temporal express classes, with gene content within each class similar to that of P-SSP7. Thirty-two host genes were upregulated during phage infection, including those involved in carbon metabolism, ribosome component and stress response. These upregulated genes were also similar to those of Prochlorococcus MED4 in response to infection by P-SSP7. Our study demonstrates a programmed temporal expression pattern of cyanopodoviruses and hosts during infection.