Concept
The green proteins: key players in photosynthesis
GrInSun (Green Proteins at the Interface between Sun Energy and Biosphere) is an European Research Commission (ERC) Advanced Grant multidisciplinary project pursuing new discoveries and translational research in photosynthesis.
Green proteins bind chlorophyll and form the antenna system of plants and microalgae which absorb photons and kickstart the earliest steps of photosynthetic reactions.
Also, green proteins can act as molecular switches protecting the photosynthetic apparatus from the detrimental effects of light itself.
Therefore, the green proteins truly sit at the interface between sunlight and the biosphere, enabling light energy conversion, supporting natural ecosystems and agricultural production.
Bioengineering the green proteins: how and why?
Crops domestication has traditionally selected observable characters.
Only recently, photosynthesis has emerged as a target for improvement.
This is because the complex molecular machinery which drives its functioning can be investigated and understood using sophisticated analytical tools. Moreover, the genetic diversity of photosynthesis-related traits is still largely unexplored.
In the laboratory, it is possible to accelerate evolutionary processes, creating new genetic variability within green proteins.
Microalgae are excellent platforms to generate large collections of protein variants and rapidly assess newly acquired properties.
The gathered information can be transferred to plants to assemble rationally designed enhanced light-harvesting systems.
Enhancing light-use efficiency of the photosynthetic apparatus
One strategy pursued in the GrInSun project is to alter the absorption properties of green proteins to enhance the efficiency of energy conversion and photoprotective roles.
This can be achieved by altering the organization of chlorophyll molecules attached to green proteins to broaden and by introducing “exotic” chlorophyll types already found in nature.
In this way, it should be possible to expand the spectrum of light that can be used in photosynthesis, particularly of far-red light, which are poorly absorbed wavelengths enriched in high-density crop cultivations.
The working plan of the GrInSun project
The project aims at gaining a detailed understanding of the molecular architecture of light-harvesting systems and of the energy transfer pathways between chlorophyll molecules.
To this end, a multidisciplinary approach involving state-of-the-art analytical and genetic engineering tools will be employed.
The high throughput screening of large collections of randomly generated green protein variants (forward genetics) will be instrumental to identify structural determinants responsible for their absorption properties.
In parallel, inactivation and replacement of genes of interest encoding green proteins will be conducted in plants. This will be followed by in-depth analysis of the growth performance of the newly created phenotypes under different light regimes.
Expected project deliverables
Establishment of genetically engineered plants of the model species Arabidopsis thaliana with altered light absorption properties. Eventually, the same modifications are expected to be implemented in crop species tailored for high-density cultivation.
Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or European Research Council Executive Agency. Neither the European Union nor the granting authority can be held responsible for them.