We study plant species across a broad range of evolutionary diversity; including angiosperms and conifers, lycophytes and mosses, green algae and cyanobacteria. Our primary aim is to understand the organization and dynamics of electron transport in thylakoid membranes of oxygen-evolving photosynthetic organisms, with a focus on an array of different regulation mechanisms that are vital for plants and cyanobacteria to thrive in the fluctuating conditions of their natural growth environments.
Photosynthesis stores solar energy in the form of chemical energy. Light reactions take place in thylakoid membranes of plant chloroplasts and cyanobacteria, where sunlight is collected by light-harvesting complexes and used to drive electron transport through large pigment protein complexes (PSII and PSI). Photosynthesis is tightly regulated to avoid excess light energy and to control the rate of intersystem electron transport as well as the delivery of reducing power to various electron acceptors. Photosynthetic regulation is especially important in the fluctuating growth environment in order to avoid dangerous side-reactions that can damage the cell. Most of the protein components of the photosystems have been well conserved across photosynthetic organisms, from cyanobacteria to higher plants. However, a remarkable diversity of photosynthetic regulation strategies has evolved alongside photosynthesis.
We study higher plants including angiosperms and conifers, as well as lycophytes and mosses, green algae and cyanobacteria, to disclose the composition, function and regulation of core photosynthetic complexes and light-harvesting pigment-protein complexes. We are especially interested in the evolutionary and mechanistic details of photosynthetic regulation, including ROS production, damage and turnover of PSI and PSII, thylakoid protein phosphorylation, excitation quenching and photorespiration. We use biophysics, proteomics, transcriptomics and spectroscopic techniques to study the impacts of the ever-fluctuating environment on photosynthetic electron transport, light-harvesting, oxidative stress and retrograde signaling.
Photosynthetic regulation maintains energy balance and coordinates the utilization of solar energy with changing metabolic needs. Our research has detailed the protective effects of photosynthetic regulation under various environmental conditions, and has traced the evolution of different light-harvesting and regulation mechanisms to the niche environmental challenges facing different photosynthetic species. Furthermore, changes in photosynthetic energy balance have been found to instigate specific signaling pathways that communicate with the wider cell. Our work is used to identify and assess potential targets for improving the productivity and tolerance of photosynthetic organisms for food, feed and fuel production in the emerging bioeconomy.