Identification of a plasma membrane complex that interacts with phyB to regulate ROS production

Area of Science:

• Plant molecular biology
• Plant signaling pathways
• Reactive oxygen species metabolism

Background:

• Reactive oxygen species (ROS) are crucial signaling molecules in plants, influencing growth, development, and environmental responses.
• RBOHD-mediated ROS production is modulated by PHYTOCHROME B (phyB), which is itself regulated by FERONIA phosphorylation.
• This suggests a potential interaction network involving FERONIA, phyB, and RBOHD in stress-induced ROS regulation.

Purpose of the Study:

• To investigate the interactions between FERONIA, phyB, and RBOHD under excess light (EL) stress in Arabidopsis thaliana.
• To elucidate the roles of FERONIA kinase activity and phyB phosphorylation in regulating RBOHD-driven ROS production.
• To identify other potential interacting partners involved in this stress response pathway.

Main Methods:

• Immunoprecipitation and proximity labeling techniques were employed to identify protein-protein interactions.
• Split-luciferase assays were used to confirm interactions in vivo.
• Functional validation assays assessed the necessity of identified proteins for ROS production under EL stress.

Main Results:

• Direct interactions were confirmed between phyB, RBOHD, and FERONIA.
• FERONIA's kinase activity and its phosphorylation of phyB are essential for RBOHD-dependent ROS production during EL stress.
• CYSTEINE-RICH RECEPTOR LIKE KINASE 10 (CRK10) and PLASMA MEMBRANE INTRINSIC PROTEIN 2;6 (PIP2;6) were identified as interacting partners of RBOHD and phyB, and are required for EL-induced ROS production.

Conclusions:

• A novel plasma membrane complex involving FERONIA, RBOHD, CRK10, and PIP2;6, which interacts with phyB, regulates ROS production in Arabidopsis under stress.
• This protein complex integrates multiple signaling pathways, playing a key role in plant stress adaptation.
• The findings provide new insights into the molecular mechanisms governing ROS homeostasis and signaling in plants.