Seminar Title: Transcriptomic and Proteomic Study on Host–Phage Interactions of Marine Cyanobacterium Prochlorococcus

Speaker: Miss FANG Xiaoting

Date: 12 December 2018, Wednesday
Time: 9:30 am
Venue: Room 4475 (Lift no. 25-26), 4/F Academic Building, HKUST

Abstract:
Marine picocyanobacterium Prochlorococcus contributes to a vital proportion of the global primary production, especially in the nutrient-limited oligotrophic oceans. Cyanophages that infect Prochlorococcus redirect the intracellular metabolism of their cyanobacterial host, releasing a variety of dissolved organic matter (DOM) from the lysed cells, eventually affecting the global biogeochemical cycling substantially. Here we have studied the host–phage interactions of the marine cyanobacterium Prochlorococcus, combining approaches from omics-techniques, as well as physiological and biochemical assays. Analysis of the within-host proteome during phage infection is essential to revealing the molecular dynamics of host–phage interactions. As a consequence, we have conducted quantitative proteomics in two sets of relatively well-defined host–phage systems—the cyanopodovirus P-SSP7 and cyanomyovirus P-HM2 both infecting Prochlorococcus MED4. This work has been first time characterised the quantitative proteomics during infection of Prochlorococcus by marine cyanophages, which provide further insight into the infection dynamics and mechanism on both translational and post-translational level. Meanwhile, the lysis-induced phytoplankton-released DOM is important for the marine food web because it supports the growth of heterotrophic microorganisms. However, the impact of viral DOM on the uninfected phytoplankton remains largely unknown. We therefore examined the cyanobacterial responses towards viral lysis products. First, we have determined the elemental concentrations and amino acid compositions of the phytoplankton-derived DOM. Employing transcriptomic sequencing and biochemical assays, DOM-responsive genes and metabolism of the host Prochlorococcus have been revealed and further validated. Collectively, the combined work presented here has advanced the understanding of host–phage interactions of marine cyanobacterium Prochlorococcus, linking the infection dynamics with molecular basis on various levels.

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