GbWAKL20 Phosphorylates GbNFYB8 to Modulate Verticillium Wilt Resistance in Cotton

Verticillium wilt (VW), caused by Verticillium dahliae (Vd), is a major threat to cotton production worldwide. Wall-associated receptor-like kinases (WAKLs) are critical for plant-environment communication and fungal pathogen resistance, yet their regulatory mechanisms in cotton remain unclear. Through genomic and transcriptomic analysis, coupled with disease resistance assays, we identified a WAKL gene from Gossypium barbadense acc. Hai7124, named GbWAKL20, was involved in VW resistance. GbWAKL20 was significantly induced upon Vd infection. Silencing GbWAKL20 in Hai7124 compromised VW resistance, suppressed the mitogen-activated protein kinase (MAPK) cascade and salicylic acid (SA) signaling pathway, whereas its ectopic overexpression in Arabidopsis enhanced immune responses. Upon sensing extracellular stress signals at the plasma membrane, GbWAKL20 accumulates and transmits these signals to the nucleus via endoplasmic reticulum-mediated Golgi vesicle transport. GbWAKL20 interacts with the transcription factor GbNFYB8 and promotes its nuclear translocation through phosphorylation. GbNFYB8 binds to CCAAT elements in promoters of immunity-related genes and activates their expression. Silencing GbNFYB8 reduces VW resistance in cotton. GbWAKL20-mediated phosphorylation enhances transcriptional activation activity of GbNFYB8, further amplifying disease resistance responses and improving plant resistance. Our results highlight the significance of the GbWAKL20-GbNFYB8 module in defending against VW and provide novel insights into plant immune signaling pathways.