WRKY Transcription Factors: Integral Regulators of Defence Responses to Biotic Stress in Crops.

Crops are continually challenged by biotic stresses, including fungal, bacterial and viral pathogens and insect pests, which cause substantial yield and quality losses worldwide. WRKY transcription factors constitute a plant-specific and functionally diverse family that is central to immune regulation. Recent advances in genomic resources and multi-omics approaches have accelerated the identification and functional characterisation of WRKYs in crops. This review summarises the structural features and classification of WRKY genes and their genome-wide distribution across crop species. It also synthesises WRKY-centred regulatory modules that mediate resistance to major classes of biotic stress. In antifungal defence, WRKYs reinforce pattern- and effector-triggered immunity, modulate protein stability and reprogramme secondary metabolism. In antibacterial immunity, they link bacterial perception to cell wall remodelling and hormone and redox signalling. WRKYs also activate PR gene expression, cell wall fortification, RNA interference and programmed cell death to combat oomycete and viral pathogens and insect pests. Overall, WRKYs function as context-dependent transcriptional hubs. They integrate immune signalling with hormonal crosstalk, remodel defence gene networks, and redirect secondary metabolism, thereby shaping resistance outcomes under biotic stress. The review examines WRKY-mediated defence-growth trade-offs and explores opportunities to harness WRKY-centred networks for breeding and engineering broad-spectrum, durable disease and pest resistance. It also highlights how integrating multi-omics with precision genome editing, synthetic biology, gene-drive technologies and artificial intelligence could establish WRKYs as central molecular targets for improving crop resilience and performance.