Effects of the soil treatment with a corn gluten-derived protein hydrolysate on table grape berry transcriptome

Protein hydrolysate (PH)-based biostimulants offer a cost-effective and sustainable approach for regulating physiological processes in plants to stimulate growth and improve quality characteristics and stress tolerance. The effectiveness of treatments using different categories of biostimulants on grapevine growth and development has been well-documented for foliar applications compared to soil applications. Considering table grapes, colour is an important quality trait that can be modulated by vineyard practice, including fertilization. In this context, we have evaluated the effects of an environmentally friendly biostimulant, a protein hydrolysate derived from corn gluten, on the berry developmental process of the Black magic table grape. When applied to the soil at veraison, the biostimulant increased the cluster weight, berry diameter, and colour just 14 days after application. The transcriptome analysis of berries carried out at the same sampling time point underlined that the treatment speeds up the ripening process. Overall design: To evaluate the effects of the treatment with a corn gluten-derived protein hydrolysate (GDPH, SURNAN®) on berry ripening, we applied veraison the products by ferti-irrigation to Black magic vines. As a control, we applied urea in the same mode (46% N) in a quantity to apply the same dose of nitrogen (N) applied with the protein hydrolysates (1.25 kg ha-1). The experiment was organized by a randomized complete block design comprising four plots (biological replicates) for each treatment. Each plot contained 7 vines. RNAseq analysis was carried out with a pool of berries sampled after 14 days from the 7 plants for three out of the four plots (biological replicates). We sampled the berries after 14 days of treatment and we identified the by RNAseq analysis the differentially expressed transcripts between the berries of plants treated with the protein hydrolysates and the control plants.