Project Details
Projekt
Photosynthesis genes in phage genomes-elucidation of their role in cyanobacteria-phage interaction
Subject Area
Metabolism, Biochemistry and Genetics of Microorganisms
Term
since 2021
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 464877090
Marine cyanobacteria of the genera Synechococcales and Prochlorococcales are the most abundant prokaryotic phototrophs in the world’s ocean. These cyanobacteria are highly challenged by viral infection, with up to 40 % of the bacterial population being infected by phages. In the marine environment, cyanophages have a significant impact on ecology, evolution, and biogeochemical processes. They are involved in nutrient recycling, host population control, niche adaptation and serve as vehicles for gene transfer. Infection of a bacterium by a phage transforms the host cell into a so-called virocell which shifts its normal cellular activities towards producing viral components. In this state, significant changes are induced in various host metabolic pathways. Cyanophages furthermore expand the virocell metabolism by introducing auxiliary metabolic genes (AMGs) often related to photosynthesis and light-harvesting to supplement the required metabolic demand. Within the second funding period of this priority program, the role of AMGs in phage-host interaction will be investigated exemplified by ФcpeT from cyanophage Syn9 infection Synechococcus sp. WH8109. ФcpeT has similarity a cyanobacterial phycobiliprotein lyase, involved in the maturation of the light harvesting phycobilisome. ФCpeT ‘s function in the virocell, its interaction with host proteins, and its dispensability will be investigated. Specifically, the virocell of Synechococcus sp. WH8109 challenged by the cyanophages Syn9 and a recently generated recombinant ФcpeT deletion phage will be explored. Using proximity labelling followed affinity enrichment mass spectrometry, protein interaction partners of ФCpeT will be identified. Mass spectrometry-based proteomics of the wild type and recombinant virocells will provide a glimpse of the proteomic content with emphasis on those proteins related to light harvesting and pigment biosynthesis. Furthermore, metabolomics will help to elucidate how virocell metabolism is rewired during infection. All strategies aim to gain insight into the role of ФCpeT during infection and how it shapes the virocell metabolism. Additionally, physiological parameters related to photosynthesis (light saturation points, O2 release, pH), as well as ecological parameters such as nutrient release (protein, glycogen, phosphates), will be evaluated in host and virocells. Finally, given our strong expertise in protein biochemistry, ФCpeT’s function will be investigated on the molecular level and its biochemical function compared to that of the host counterpart. Overall, this project will add to the global knowledge base on the role of cyanophages in regulating oceanic photosynthesis and nutrient cycling.
DFG Programme
Priority Programmes
