Thylakoid Rhodanese-like Protein-Ferredoxin:NADP⁺ Oxidoreductase Interaction Is Integrated into Plant Redox...

Area of Science:

• Plant Physiology
• Photosynthesis
• Redox Biology

Background:

• Ferredoxin:NADP+ oxidoreductase (FNR) catalyzes the final electron transfer in photosynthesis.
• Thylakoid membrane proteins TROL and Tic62 recruit FNR to the membrane.
• Absence of TROL enhances superoxide removal, suggesting a role in regulating electron flow and ROS.

Purpose of the Study:

• To investigate the hypothesis that the FNR-TROL complex triggers chloroplast reactive oxygen species (ROS) scavenging networks.
• To explore the interaction between TROL and thylakoid ascorbate peroxidase (tAPX).

Main Methods:

• Tandem affinity purification coupled with mass spectrometry (MS) to confirm protein interactions.
• Electron paramagnetic resonance (EPR) spectroscopy using DMPO to detect superoxide radicals.
• Immunohistochemical analysis of glutathione levels in Arabidopsis.

Main Results:

• Confirmed the interaction between TROL and FNR, and identified a potential interaction between TROL and tAPX.
• Overexpression of TROL (TROL OX) in Arabidopsis led to increased superoxide propagation under high light stress.
• TROL OX plants exhibited elevated glutathione levels, indicating increased ROS scavenging activity.

Conclusions:

• The FNR-TROL complex is implicated in initiating downstream ROS scavenging pathways.
• Increased membrane-bound FNR due to TROL overexpression enhances sensitivity to oxidative stress.
• TROL plays a significant role in regulating redox homeostasis and ROS defense mechanisms in plants.