The Cysteine-Rich Secretory Protein TaSCP1-6B Modulates Resistance to Fusarium graminearum in Wheat

Common wheat (Triticum aestivum L.) is a major food crop that is widely cultivated worldwide. Fusarium head blight (FHB) caused by Fusarium graminearum poses a growing threat to wheat yield and quality. Cysteine-rich secretory proteins (SCPs) mediate plant defense, but the role of wheat TaSCPs in FHB resistance remains unclear. Here, we report that TaSCP1-6B, a conserved, positively selected SCP gene upregulated during early Fg infection, enhances FHB resistance by modulating programmed cell death. A disease-resistant haplotype containing a 10-amino acid insertion was identified in landraces. Functional validation in both Arabidopsis and common wheat confirmed that TaSCP1-6B positively regulates the Fg resistance. TaSCP1-6B^Hap.1 mediates stronger FHB resistance than does TaSCP1-6B^Hap.0. The intact protein structure of TaSCP1-6B was essential for inducing cell death. These findings reveal the role of TaSCP1-6B in enhancing wheat resistance to Fg and provide assistance for further understanding of the mechanism of TaSCP1-6B in the resistance of wheat to FHB.