Identification of a putative RBOHD-FERONIA-CRK10-PIP2;6 plasma membrane complex that interacts with phyB to regulate ROS production in <i>Arabidopsis thaliana</i>

SUMMARY Reactive oxygen species (ROS) regulate plant growth, development, and responses to the environment. ROS production by the RESPIRATORY BURST OXIDASE PROTEIN D (RBOHD) protein was recently shown to be regulated by PHYTOCHROME B (phyB), and phyB was found to be phosphorylated by FERONIA, highlighting the possibility that these three proteins interact to regulate ROS levels during stress. Immunoprecipitation and proximity labelling, followed by split-luciferase and functional validation assays, were used to study the interactions between FERONIA, phyB, and RBOHD during excess light (EL) stress in Arabidopsis thaliana . We reveal that phyB and FERONIA interact with RBOHD, that phosphorylation of phyB by FERONIA, as well as the kinase activity of FERONIA, are required for RBOHD-driven ROS production in response to EL stress, and that CYSTEINE-RICH RECEPTOR LIKE KINASE 10 (CRK10) and PLASMA MEMBRANE INTRINSIC PROTEIN 2;6 (PIP2;6) interact with RBOHD and phyB and are also required for EL-driven RBOHD ROS production. Our findings uncover the existence of a putative plasma membrane complex between FERONIA, RBOHD, CRK10, and PIP2;6 that interacts with phyB to regulate ROS production in Arabidopsis in response to stress. This complex could play a canonical role in the integration and regulation of multiple signaling pathways in plants. Plain Language Summary We identified a complex between several different proteins at the plasma membrane that interacts with the light and temperature receptor protein phytochrome B to regulate reactive oxygen species formation during stress in plants. This complex could be involved in the regulation and integration of multiple abiotic and biotic signals in plants. ten ten