DYNAMIN-RELATED PROTEIN DRP1A functions with DRP2B in plant growth,flg22-immune responses,and endocytosis |
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| Authors: | Gayani Ekanayake John M Smith Kody B Jones Hayley M Stiers Samuel J Robinson Erica D LaMontagne Paxton H Kostos Peter V Cornish Sebastian Y Bednarek Antje Heese |
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| Institution: | 1. Interdisciplinary Plant Group (IPG), Division of Biochemistry, University of Missouri–Columbia, Columbia, Missouri 65211;2. Division of Plant Sciences, University of Missouri–Columbia, Columbia, Missouri 65211;3. Department of Biochemistry, University of Wisconsin–Madison, Madison, Wisconsin 53706 |
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| 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. A plant-specific large dynamin GTPase is required for plant responses against bacterial pathogens and, with another dynamin, regulates the cell surface composition for plant growth and defense. |
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