Pathogen-Induced Cell Wall Remodeling and Immune Signaling in Plants.

The plant cell wall is a primary barrier to pathogen invasion and a dynamic extracellular interface involved in defense signaling. During infection, pathogens remodel the wall through cell wall-degrading enzymes and effectors, whereas plants reinforce the wall and perceive wall-derived damage-associated molecular patterns that activate immune responses. Recent studies have refined this view by challenging a simple wallassociated kinase-centered model of oligogalacturonide perception, linking MIK2-associated peptide-receptor pathways to pattern-triggered immunity, and showing that pathogens can chemically modify wall-derived fragments to alter their elicitor activity. In addition to chemical cues, pathogen-induced wall perturbation can also affect physical properties such as wall stiffness, porosity, membrane tension, and localized deformation, although how these inputs are integrated during infection remains incompletely understood. This review summarizes current understanding of pathogeninduced cell wall remodeling, wall-derived immune signaling, receptor-associated wall integrity pathways, and their implications for crop disease resistance. We highlight emerging connections among wall chemistry, wall mechanics, peptide signaling, hormone regulation, and growth-defense trade-offs as important directions for understanding wall-mediated immunity.