TaMPK3 mediates synergistic damage from Fusarium crown rot and drought in wheat

Fusarium crown rot (FCR) is a hard-to-control wheat disease prevalent in arid and semi-arid regions. However, the relationship between arid conditions and FCR disease remains unclear. Here, we confirm that drought stress exacerbates the severity of FCR, and that FCR intensifies drought-induced damage. Integrated transcriptome analysis indicates that TaMPK3 gene exhibits distinctly opposite expression patterns under these two stress conditions. Functional identification verifies that TaMPK3 positively regulate FCR resistance while negatively influencing drought tolerance. Upon TaMPK3 gene knockout, the mutually reinforcing effect between drought and FCR is eliminated. TaMPK3 is found to modulate TaWRKY26 activity to regulate the expression of sterol synthesis gene clusters, thereby influencing FCR resistance. Within this cluster, the key gene TaCYP51H37 significantly enhances FCR resistance. Combined with our findings that TaMPK3 decreases drought tolerance through ABA signaling pathway, this study proposes a molecular model in which TaMPK3 mediates the synergistic damage caused by drought and FCR.