PsWRKY75 orchestrates lignin biosynthesis and H₂O₂ metabolism to modulate disease resistance: a physiological and biochemical mechanism in Prunus sibirica L.

Prunus sibirica L., an economically and ecologically significant Asian endemic species, faces severe pathogenic threats, yet its disease resistance mechanisms remain poorly understood. Using RNA-seq of pathogen-infected leaves, we identified PsWRKY75 as a potential resistance gene. Heterologous overexpression in poplars showed that PsWRKY75 enhanced disease resistance, promoting lignin and H₂O₂ accumulation in leaves. Through RNA-seq and promoter analysis, PsWRKY75 was identified as an upstream regulator of the H₂O₂-producing gene PsRbohB and lignin biosynthesis gene PsLFP1, validated by yeast one-hybrid, EMSA, and dual luciferase assays. Pathogen infection upregulates PsWRKY75, which directly activates PsRbohB and PsLFP1 to enhance lignin/H₂O₂ accumulation, thereby strengthening disease resistance. This study reveals PsWRKY75 as a novel integrator of H₂O₂ signaling and lignin biosynthesis, providing genetic resources for woody plant disease resistance improvement via physiological and biochemical engineering.