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

Abstract

Grapevine is one of the most extensively cultivated fruit crops, playing a crucial role in the economies of many grape-growing regions around the world. However, grape production currently faces significant challenges due to climatic adversities and the pressing need to adopt sustainable production models. The use of plant biostimulants offers a promising and viable alternative to traditional practices, sustainably enhancing grape production and quality even under adverse conditions.

In this context, we tested a maize gluten-derived protein hydrolysate (GDPH) on the Black Magic early table grapevine variety. The product, obtained from the enzymatic hydrolysis of the wet-milling process by-products, was applied at the soil by drenching to evaluate its effects on yield, grape ripening, and fruit quality.

The GDPH, administered at veraison, positively affected many parameters as early as 14 days post-application. It increased anthocyanin and sugar concentrations and berry diameter while maintaining optimal levels of berry firmness. Through transcriptomic analysis of the berries, we found that the GDPH accelerated the berry ripening process by up-regulating the expression of genes involved in anthocyanin biosynthesis and enhancing the modulation of key developmental regulators in berries. Furthermore, the selective modulation of genes related to cell wall metabolism explained the observed preservation of berry firmness. Our findings suggest that GDPH treatments may boost grapevines resilience by increasing the tolerance to both abiotic and biotic stresses, as evidenced by the impact on several genes related in such responses. Taken together our results highlight the efficacy of this plant-derived biostimulant in enhancing berry coloration with minimal impact on fruit texture, which is particularly important for table grape production. The demonstrated positive effects on berry pigmentation and the ability to enhance quality parameters emphasize the need for further research to elucidate its mechanisms of action. Ultimately, optimizing its application in agricultural practice will help unlock its full potential as a plant biostimulant.