The soil application of a plant-derived protein hydrolysate speeds up selectively the ripening-specific processes in table grape.

Plant-derived biostimulants have gained attention in agricultural practices for their potential to enhance crop quality and resilience. In this study, we investigated the effects of applying a maize gluten-derived protein hydrolysate at the soil level in vineyards on berry quality in a table grape variety, the Black Magic early table grapevine, during veraison. Our results demonstrate significant improvements in various parameters 14 days after application, including increased anthocyanin levels, enhanced sugar accumulation, and larger berry diameter while maintaining berry firmness. Transcriptomic analysis revealed mechanisms underlying these effects, highlighting the biostimulant's ability to expedite ripening processes while selectively modulating genes associated with cell wall metabolism, thus explaining the observed preservation of berry firmness. Furthermore, the treatment with a gluten-derived protein hydrolysate enhanced the grapevine's resilience to abiotic and biotic stresses, and several related genes were affected. This study sheds light on the potential of plant-derived biostimulants in grapevine cultivation, emphasizing the need for further research to elucidate their mechanisms and optimize agricultural practices.