PAMP (Pathogen-associated Molecular Pattern)-induced Changes in Plasma Membrane Compartmentalization Reveal Novel Components of Plant Immunity

TLDR

Plasma membrane compartmentalization spatiotemporally regulates cell‑autonomous immune signaling in animal cells. The study aimed to map immediate early protein dynamics at the plant plasma membrane upon flg22 exposure. Using quantitative mass spectrometry on detergent‑resistant membranes and reverse genetics, the authors examined protein changes and tested candidate roles in flg22‑triggered responses. Rapid, profound alterations in DRM protein composition were observed after flg22, including proton ATPases and receptor‑like kinases such as FLS2, and loss‑of‑function mutants of DET3, AHA1, and FER displayed impaired ROS production, MAPK activation, stomatal closure, and altered bacterial infection, demonstrating dynamic membrane compartmentalization in PAMP signaling.

Abstract

Plasma membrane compartmentalization spatiotemporally regulates cell-autonomous immune signaling in animal cells. To elucidate immediate early protein dynamics at the plant plasma membrane in response to the bacterial pathogen-associated molecular pattern (PAMP) flagellin (flg22) we employed quantitative mass spectrometric analysis on detergent-resistant membranes (DRMs) of Arabidopsis thaliana suspension cells. This approach revealed rapid and profound changes in DRM protein composition following PAMP treatment, prominently affecting proton ATPases and receptor-like kinases, including the flagellin receptor FLS2. We employed reverse genetics to address a potential contribution of a subset of these proteins in flg22-triggered cellular responses. Mutants of three candidates (DET3, AHA1, FER) exhibited a conspicuous defect in the PAMP-triggered accumulation of reactive oxygen species. In addition, these mutants showed altered mitogen-activated protein kinase (MAPK) activation, a defect in PAMP-triggered stomatal closure as well as altered bacterial infection phenotypes, which revealed three novel players in elicitor-dependent oxidative burst control and innate immunity. Our data provide evidence for dynamic elicitor-induced changes in the membrane compartmentalization of PAMP signaling components.