Arabidopsis proline dehydrogenase contributes to flagellin mediated PAMP-triggered immunity by affecting RBOHD

GEORGINA FABRO; YANINA SOLEDAD RIZZI; MARIA ELENA ALVAREZ

MOLECULAR PLANT-MICROBE INTERACTIONS

AMER PHYTOPATHOLOGICAL SOC

Año: 2016

0894-0282

Plants activate different defense systems to counteract the attack of microbial pathogens. Among them, the recognition of conserved microbial/pathogen associated molecular patterns (MAMPs/PAMPs) by pattern-recognition receptors stimulates MAMP/PAMP-triggered immunity (MTI/PTI). In recent years, the elicitors, receptors and signaling pathways leading to PTI have been extensively studied. However, the contribution of organelles to this program deserves further characterization. Here, we studied how processes altering the mitochondrial electron transport chain (mETC) influence PTI establishment. With particular emphasis we evaluated the effect of proline (Pro) dehydrogenase (ProDH), an enzyme that can load electrons into the mETC and regulate the cellular redox state. We found that mETC uncouplers (antimycin/rotenone) and MnSOD deficiency impair flg22-induced responses, such as accumulation of reactive oxygen species (ROS) and bacterial growth limitation. ProDH mutants also reduce these defenses, decreasing as well callose deposition. Using ProDH inhibitors and ProDH inducers (exogenous Pro treatment) we showed that this enzyme modulates the generation of ROS by the plasma membrane respiratory burst NADPH oxidase homolog D (RBOHD). In this way, we contribute to the understanding of mitochondrial activities influencing early and late PTI responses, and the coordination of the redox-associated mitochondrial enzyme ProDH with defense events initiated at the plasma membrane.