Tweaking Photosynthesis: FNR-TROL Interaction As Potential Target for Crop Fortification

Photosynthesis not only supplies plants with needed energy for growth and nutrient storage, but links light-to-chemical energy conversion with redox regulatory networks of the entire cell. By modulating photosynthetic electron flow, plants can adapt to constantly changing light and environmental conditions. Different mechanisms direct electrons formed during light reactions to either energy-conserving or energy-dissipating pathways. Recently described dynamic interactions of the flavoenzyme ferredoxin:NADP+ oxidoreductase (FNR) with protein TROL represent elegant molecular switch that can partition electrons downstream of photosystem I. FNR-TROL bifurcation can control energy transfer to either linear flow, which results in NADPH production, or to the rapid electron sink that efficiently prevents reactive oxygen species propagation. Plant genome editing of TROL represents an unexploited alley for improvement of plant stress and defense responses, productivity, and eventually agricultural yield.