Photosynthesis in far-red: from cyanobacteria to plants

Introduction

Photosynthesis, the process that sustains life on our planet by generating food and supplying oxygen, is astonishingly inefficient: less than 1% of accessible solar energy is converted into biomass by a crop. Improving photosynthesis is thus a promising approach to meet the increasing demand for food production.

Importance of Light Utilization

The capacity to optimally harness light is a crucial factor in the photosynthetic process, especially in light-limited environments. However, plants only utilize the visible part of the solar spectrum (400-700 nm), which results in more than 50% of the photons reaching the Earth’s surface being discarded.

Limitations in Crop Growth

This represents an important limitation, especially for crops, as plants in the field are close together, and the light reaching the lower leaves is almost exclusively far-red (>700 nm). Until recently, it was believed that 700 nm was the thermodynamic limit of oxygenic photosynthesis.

Discovery of Cyanobacteria

However, the discovery of several species of cyanobacteria, the prokaryotic ancestors of plant chloroplasts, that can grow in far-red light has shown that this is not the case.

Research Questions

• How can cyanobacteria use far-red light?
• Would it be possible to introduce the same mechanisms into plants to expand their spectral coverage and increase light-use efficiency?

Project Objectives

This project aims to address these questions by elucidating the mechanisms underlying far-red light acclimation in cyanobacteria and re-designing them to be compatible with the photosynthetic system of plants.

Key Areas of Focus

This requires addressing knowledge gaps related to:

1. The synthesis of novel pigments
2. Their integration into photosynthetic proteins
3. Their impact on photochemical efficiency and photosynthesis regulation

Methodology

For this, I will combine in vivo, in vitro, and in silico approaches, ranging from molecular biology to ultrafast spectroscopy and modeling, which is the trademark of my group.

Expected Outcomes

This project will determine if implementing a far-red response in plants is viable, beneficial, and a potential strategy for crop enhancement.