Battle Beneath the Wall: Modulating Cell Wall-Associated Kinase (WAK) and WAK-Likes (WAKLs) to Cope With Biotic and Abiotic Stresses in Plants.

Abstract

Wall-associated kinases (WAKs) and WAK-likes proteins (WAKLs) comprise a unique receptor-like kinases subfamily mediating cell wall-cytoplasmic communication. Structurally defined by extracellular pectin-binding regions and intracellular kinase domains, they integrate developmental and environmental cues. This review summarises recent advances across plant species, highlighting WAK/WAKLs as dual regulators of growth and stress adaptations. They govern cell expansion, vascular differentiation, and resource allocation, influencing traits like grain size and leaf senescence. Under abiotic stress such as salt, drought, extreme temperatures, and metal toxicity, these proteins enhance resilience through ion homoeostasis regulation, cell wall remodelling, and antioxidant pathway activation. During biotic interactions, they recognise PAMPs/DAMPs, triggering immunity via chitin receptor interactions, MAMP cascades, and transcription factor networks while balancing growth-defence trade-offs. Their potential for practical application is evidenced by agronomically significant targets such as OsWAK74, which is linked to grain yield, and ZmWAK, associated with disease resistance. To effectively connect mechanistic insights with crop improvement, it is essential to systematically explore the functional divergence and signalling flexibility of WAKs/WAKLs across different species, aiming to develop crops that are resilient to climate challenges.