Rootstock-enhanced gray mold resistance through phytohormonal crosstalk and transcriptional reprogramming

Botrytis cinerea causes gray mold disease in grapevines (Vitis vinifera), resulting in substantial yield and quality losses. While 'Kober 5BB (Vitis berlandieri × Vitis riparia) is widely used as a rootstock for its adaptability and resilience, its influence on scion resistance to gray mold remains unexplored. We integrated antioxidant activity assays, phytohormone profiling, and transcriptome sequencing to evaluate resistance differences between self-grafted and 'Kober 5BB'-heterografted 'Munake' grapevines. During early infection, heterografted plants exhibited significantly elevated activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPX), alongside higher concentrations of salicylic acid (SA), abscisic acid (ABA), and methyl jasmonate (MeJA). Transcriptome analysis revealed a robust activation of defense-related genes in heterografted scions, specifically pathogenesis-related proteins (Vitvi03g00752, log2FC = 5.10) and jasmonic acid pathway lipoxygenases (Vitvi06g00153, log2FC = 1.57), which were significantly suppressed in self-grafted controls. These findings demonstrate that rootstock selection modulates scion defense responses through coordinated biochemical and transcriptional mechanisms, offering a practical strategy for enhancing disease resistance in viticulture. Future research should explore molecular networks mediating rootstock-scion communication and validate these mechanisms in field conditions across various cultivars and stresses.