DYNAMIN-RELATED PROTEIN DRP1A functions with DRP2B in plant growth, flg22-immune responses, and endocytosis

Abstract

Ligand-induced endocytosis of the immune receptor FLAGELLIN SENSING2 (FLS2) is critical for maintaining its proper abundance in the plasma membrane (PM) to initiate and subsequently down regulate cellular immune responses to bacterial flagellin or flg22-peptide. The molecular components governing PM abundance of FLS2, however, remain mostly unknown. Here, we identified Arabidopsis (Arabidopsis thaliana) DYNAMIN-RELATED PROTEIN1A (DRP1A), a member of a plant-specific family of large dynamin GTPases, as a critical contributor to ligand-induced endocytosis of FLS2 and its physiological roles in flg22-signaling and immunity against Pseudomonas syringae pv. tomato DC3000 bacteria in leaves. Notably, drp1a single mutants displayed similar flg22-defects as those previously reported for mutants in another dynamin-related protein, DRP2B, that was previously shown to colocalize with DRP1A. Our study also uncovered synergistic roles of DRP1A and DRP2B in plant growth and development as drp1a drp2b double mutants exhibited severely stunted roots and cotyledons, as well as defective cell shape, cytokinesis, and seedling lethality. Furthermore, drp1a drp2b double mutants hyperaccumulated FLS2 in the PM prior to flg22-treatment and exhibited a block in ligand-induced endocytosis of FLS2, indicating combinatorial roles for DRP1A and DRP1B in governing PM abundance of FLS2. However, the increased steady-state PM accumulation of FLS2 in drp1a drp2b double mutants did not result in increased flg22 responses. We propose that DRP1A and DRP2B are important for the regulation of PM-associated levels of FLS2 necessary to attain signaling competency to initiate distinct flg22 responses, potentially through modulating the lipid environment in defined PM domains.

Lipid Signaling Requires ROS Production to Elicit Actin Cytoskeleton Remodeling during Plant Innate Immunity

“…It is possible that the regulation of RBOHD trafficking, membrane dynamics, or immune complex formation by the actin cytoskeleton are critical to balance ROS generation in plant cells. Other negative regulators of ROS production include DYNAMIN-RELATED PROTEIN 1A and 2B (DRP1A and DRP2B) that are implicated in clathrin-mediated endocytosis of FLS2 [ 41 , 72 ]. Combining these reports with our data, it is possible that regulation of RBOHD vesicular trafficking is an important mechanism to attenuate ROS signaling in response to biotic and abiotic stimuli.…”

The phloem-resident OCTOPUS protein is a novel regulator of flg22-induced responses in Arabidopsis thaliana

“…Root length measurements were performed as described (33). 10-day-old seedlings grown under the conditions described, were traced using Fiji Free-hand tool.…”

Quantitative Time-Course Analysis of Osmotic and Salt Stress inArabidopsis thalianausing Short Gradient Multi-CV FAIMSpro BoxCar DIA

“…For example, components of ABA signaling, ranging from perception to transduction, were found to be controlled by the endocytic trafficking pathway (111,112). However, knowledge of the proteins responsible for vesicular transport under abiotic stress remain limited (113)(114)(115)(116). A previous study showed that over-expression of VESICLE-ASSOCIATED MEMBRANE PROTEIN 711 (VAMP711; AT4G32150) boosts drought stress by dampening PM H + -ATPase activity (116), consistent with our results that VAMP711 protein levels are up-regulated in response to salt exposure (Figure 5C).…”