Deciphering the hormonal regulatory networks underlying grape berry resistance to Botrytis cinerea

Abstract

Botrytis cinerea is a major fungal pathogen affecting viticulture, causing substantial economic losses due to reduced fruit quality and subsequent yield. While the physical and chemical barriers of the grape berry are essential components of defence, the signalling mechanisms coordinating response to infection, particularly the interplay between cell wall remodelling and hormone-mediated pathways, are not yet fully understood. Here, we investigate the regulatory networks governing grape berry resistance by integrating metabolomic profiling with high-throughput transcriptomic analyses.

To characterise the hormonal fingerprint of B. cinerea infection, we analysed two Vitis genotypes displaying contrasting resistance phenotypes: the highly susceptible V. vinifera cultivar ‘Teroldego’ and the resistant interspecific hybrid ‘Souvigner gris’. Using mass spectrometry-based techniques (UHPLC-MS/MS and PTR-ToF-MS), we quantified the temporal accumulation of key phytohormones and their derivatives, including salicylic acid (SA), jasmonic acid (JA), abscisic acid (ABA), and volatile organic compounds. These measurements provided a dynamic metabolic profile of the stress response, revealing marked differences in signalling dynamics between the resistant and susceptible genotypes. To further elucidate how these hormonal cues activate downstream defence mechanisms, elicitation experiments were conducted using V. vinifera liquid cell cultures. Identified phytohormones were applied individually, and RNA-seq analyses were performed in a time-course experimental design to capture transcriptional responses associated with each signalling pathway. This approach enabled the identification of hormone-responsive gene modules and key regulatory nodes involved in the biosynthesis of specialised metabolites and potential cell wall modifications.

By integrating quantitative hormone profiling with transcriptomic network analysis, this study aims to bridge the gap between pathogen perception and physiological resistance. The identification of core regulatory networks provides a molecular framework for future breeding strategies and supports the development of cisgenic grapevine lines with enhanced and durable resistance to B. cinerea.