About the Project
Cyanophages carry auxiliary metabolic genes that hijack and rewire host photosynthesis during infection, redirecting electron flow and carbon fixation to serve viral replication. These genes represent millions of years of natural bioengineering, honed by selection to manipulate photosynthetic output. Yet the vast majority remain functionally uncharacterised and as such whether these genes can be used to engineer new photosynthetic phenotypes is unknown.
We have identified two genes from cyanophage genomes with striking, opposing effects when expressed heterologously in cyanobacteria: one dramatically rewires electron transport and boosts carbon fixation rates; the other, by contrast, suppresses it. Together they represent a natural toolkit of opposing dials for photosynthetic output — and a route to rationally engineering carbon fixation using phage-derived parts. Such engineering could ultimately be used to boost crop production or natural products derived from phototrophs.
Aims
- Screen clone libraries of cyanophage genomes in a forward genetic screen to identify further genes capable of modulating host photosynthetic activity.
- Characterise the molecular mechanism of the electron-transport-rewiring gene that enhances carbon fixation.
- Characterise the molecular mechanism of the gene that suppresses carbon fixation, and determine whether the two genes act antagonistically or independently
Methodology
Aim 1 uses clone libraries of cyanophage genome fragments expressed heterologously in cyanobacteria, screened using chlorophyll fluorescence and carbon fixation as proxies for photosynthetic activity, to identify novel candidate genes. Aims 2 and 3 combine targeted expression, electron transport chain assays, and carbon fixation measurements (¹⁴C) to dissect how each gene rewires photosynthetic electron flow, with comparative transcriptomics and protein interaction studies to pinpoint molecular targets.
