Plant energetic metabolism

Introduction

Plants are highly complex autotrophic organisms with unique developmental plasticity. Plants cover their energetic needs by utilizing light in photochemical reactions of photosynthesis. Light energy is converted into energy of electrons (that come from water molecules oxidized in photosystem II in an oxygen-evolving complex, OEC) and to proton gradient that drives the production of ATP. The ability to use (permanently store) energy from electrons (carried by reduced ferredoxin or NADPH) and ATP strongly depends on the availability of CO2 (or inorganic nitrogen and sulfur) that can be reduced to organic compounds. In C3 plants, a significant amount of captured energy is converted to heat (dissipated) in CO2 (water) shortage due to oxygenic activity of Rubisco that triggers photorespiration. While photorespiration occurs, large amounts of ammonium ions are released in mitochondria of mesophyll cells and have to be reassimilated again by glutamine synthetase in a GS/GOGAT cycle. Light intensity and CO2 availability is very variable over time which forces cells to finely regulate the conversion of light energy but also other metabolic pathways depending on external and internal conditions. Plant tissues contain not only photosynthetically active cells but also high portion of heterotrophic tissues that are fully dependent on chemical energy from sugars released during respiration, therefore, it is important to coordinate autonomic processes at a level of the whole plant. That is performed by many systems sensitive to sugar and energy levels, including trimeric G-proteins.

Major questions – areas of current research:

Even though processes involved in energetic metabolism of plants and factors that coordinate their regulation have been well described there is still a big amount of questions yet waiting to be answered:

• How did PsbO (key component of OEC) isoforms undergo their evolution and what is their function? How do these isoforms participate in fine-tuning photosynthetic activity?
• What is the role of glutamine synthetase during photorespiration in Arabidopsis thaliana?
• What is the role of heterotrimeric G-proteins in response to sugar and energy availability in plants?

Carnivorous plants attract attention in the unique way they gain nutrients. In our lab, however, we focus mainly on their genetics and breeding. 

For more information contact the head of the group Lukáš Fischer or visit us in our lab Viničná 5, 2nd floor, door 210 (at the end of the corridor).