Deciphering HPCA1’s role in OG-mediated defense and pathogen resistance

Deciphering HPCA1's role in OG-mediated defense and pathogen resistancePlants lack mobile immune cells but possess a sophisticated innate immune system crucial for survival.This system relies on the cell's ability to recognize and respond to danger signals such as Microbe-Associated Molecular Patterns (MAMPs) and Damage-Associated Molecular Patterns (DAMPs) 1 .Upon activation, intracellular responses are triggered, leading to defense gene activation, stress hormone accumulation, and systemic signaling to prepare distant tissues against potential threats 2-4 .This process, known as systemic resistance, involves the rapid transmission of reactive oxygen species (ROS) and Ca 2+ from the site of perception to unstressed tissues, creating "Ca 2+ and ROS waves" crucial for pre-emptively adapting plants against recurring infections 3, 4 .In Arabidopsis, MAMPs/DAMPs perception triggers cytosolic Ca 2+ influx and extracellular H 2 O 2 (eH 2 O 2 ) production, both essential for immunity 2 .Recent insights into the H 2 O 2 -induced Ca 2+ increases 1 (HPCA1) receptor have enhanced understanding of eH 2 O 2 perception and Ca 2+ / ROS wave propagation 5,6 .However, the systemic roles of ROS and HPCA1 in response to cell wall damage and oligogalacturonides (OGs), a class of Cell Wall-Derived DAMPs, remain poorly investigated.OGs, derived from pectin, induce local defense responses and antagonize IAA-dependent responses, but their systemic effects are largely unexplored 7 .This work aims to elucidate the mechanisms by which OG-induced signals propagate systemically and the role of HPCA1 in these processes.Using Arabidopsis, it will investigate how OGs trigger long-distance signaling, the role of HPCA1 in these processes, and the impact on growth-defense trade-offs.Understanding these pathways could lead to sustainable crop protection strategies, reducing reliance on chemical pesticides and mitigating yield losses due to diseases.