Transcriptional Modulation in Grapevine by a Biostimulant Treatment for Improved Plant Resilience to Stress Events

Grapevine (Vitis vinifera L.) is a globally significant crop increasingly affected by a variety of biotic and abiotic stresses. Plant biostimulants offer a promising approach to enhance plant resilience by modulating key physiological and metabolic processes. This study aimed to demonstrate that the preventive application of a Fabaceae-based biostimulant can prime grapevine defense pathways, thereby improving plants' ability to endure potential stress conditions. Indeed, resistance to both biotic and abiotic stresses in plants involves common pathways, including Ca²⁺ and ROS signaling, MAPK cascades, hormone cross-talk, transcription factor activation, and induction of defense genes. Grapevine leaves were subjected to high-throughput transcriptomic analysis coupled with qPCR validation 6 and 24 h following treatment application. Differentially expressed genes were visualized using MapMan to identify the major metabolic and signaling pathways responsive to the treatment. This integrative analysis revealed several defense-related pathways triggered by the biostimulant, with representative protein families showing both up- and downregulation across key functional categories. Overall, the results indicate that a wider array of pathways associated with stress tolerance and growth regulation were stimulated in treated plants compared to untreated controls. These findings support the conclusion that a preventive biostimulant application can effectively prime grapevine metabolism, enhancing its preparation to cope with forthcoming environmental challenges.