Unraveling the impact of high temperature on autophagy-linked plant immunity

LESCANO LÓPEZ IGNACIO; MESQUIDA NARDINI, M.C.; CECCHINI, NICOLAS M; LASCANO, RAMIRO H

Congreso; RAFV Conference 2023 XXXIV Argentinian Meeting of Plant Physiology; 2023

Autophagy is a key regulatory process in plant immunity, contributing to both cell survival and cell death responses. Through this mechanism, cells degrade and recycle damaged or unwanted cellular components massively and selectively. The modulation of this pathway varies in response to diverse environmental factors. This study aims to understand how different temperature increments influence components of the autophagy pathway, thereby altering defense responses in plants. To investigate potential changes in autophagy under varying temperature conditions, we analyzed plants expressing the autophagy reporter GFP-ATG8a exposed to thermomorphogenesis (30°C) and heat stress (37°C and 45°C) temperatures using Western blot and confocal microscopy assays. We observed that the autophagic flux and levels of autophagy-related proteins varied with the intensity of the applied thermal shock. Remarkably, plants exposed to higher temperatures displayed increased susceptibility to Pseudomonas syringae pv. maculicola (Pma), with the most pronounced sensitivity observed at 45°C. Moreover, we noticed a synergistic effect between Pma infection and exposure to 30°C, which led to a boost in autophagic flux and the number of autophagic bodies. Notably, the heightened susceptibility to Pma observed in autophagy mutants strongly suggests that autophagy activation plays a critical role in modulating defense responses under thermomorphogenesis conditions. This study sheds light on the intricate interplay between autophagy and plant immunity across different temperature regimes, providing valuable insights into potential strategies for enhancing plant defense in response to thermal stress.