Harvesting Light for Life: Green Proteins as the Interface between Sun Energy and Biosphere

Introduction

Life on earth feeds on photons. Photosynthesis in green algae and land plants has been the world's most successful biological process and has conquered the most diverse environments. Photosynthetic reaction centres are extremely well conserved, an unlikely basis for the ability to adapt.

Antenna Systems

Antenna systems are widely diversified, and yet only the Light-Harvesting Complexes (LHCs) have been selected for growth in the land environment. The distinctive property of GreenCut organisms lies in their light-harvesting mechanisms, which ensure efficient photon harvesting and photoprotection.

Challenges in Research

Despite being the most abundant membrane proteins on earth, binding most of the chlorophyll that makes the planet green, the secrets of LHCs are still concealed because we lack experimental systems that make possible the reverse and forward genetic analysis of LHCII proteins. Indeed, the clustered genes encoding LHCII have resisted targeting by classic genetics.

Proposed Analysis

I propose an in-depth analysis of LHCII proteins in algae and plants by deploying a new technology that we have developed with our experience in studying LHCs.

Reverse Genetics

1. Firstly, we deleted all genes encoding LHCII in model species of both land plants and green algae by genome editing.
2. We complemented plant LHCII lines with site-directed, mutated sequences, demonstrating that reverse genetics can reveal the domains involved in the regulation of photon harvesting, photoprotection, and growth.

Forward Genetics

3. Secondly, forward genetics will enable the identification of protein determinants by selecting specific phenotypes on complementing mixotrophic algal LHCII lines with randomly mutagenized sequences.

Expected Outcomes

This will lead to a map of structures and functions that identifies the specific biological role of each component of the antenna system in vivo and in vitro. The project's outcome will be the ability to design in a rational way the light-harvesting systems of plants and algae in the context of sustainable agriculture and bio-industry.