Investigation of the biostimulant activity of naringenin on anthocyanins biosynthesis: from an explanatory transcriptomic approach on Gamay callus towards a future vineyard application

Abstract

Context and purpose of the study. Anthocyanins are essential phenolic compounds in red wine, contributing significantly to colour intensity, stability, and sensory quality. However, these compounds are highly sensitive to environmental stresses, such as heatwaves and droughts exacerbated by climate change. Such conditions may disrupt the balance between technological and phenolic ripeness in grapes, leading to berries with excessive sugar levels but insufficient phenolic maturity at harvest. This study explores the potential of naringenin, a natural flavonoid and an intermediate in the anthocyanin biosynthesis pathway, to stimulate anthocyanin biosynthesis and improve phenolic maturity in Vitis vinifera L. cv Gamay cell cultures.

Material and methods. Callus cultures induced from the teinturier grape Gamay Fréaux, a variant of the white-fleshed cv Gamay that produces anthocyanin in its pulp, were employed as a simplified model to study phenolic compound biosynthesis. Three-week-old calli were treated by direct application of naringenin solutions at concentrations ranging from 0.1 mM to 1.5 mM. This approach was designed to mimic potential vineyard applications and assess dose-dependent effects. Three metrics were evaluated: i/ anthocyanin content to quantify naringenin’s impact on anthocyanin accumulation; ii/ callus viability to ensure no toxicity at effective naringenin concentrations; iii/ transcriptomic non-targeted analysis (RNA-seq) to explore naringenin’s effects on gene expression, particularly in polyphenolic pathways and stress responses.

Results. The experiments are currently in progress, with results expected soon.  Complementary analyses of anthocyanin content and callus viability will help identify the optimal treatment dose, striking a balance between maximizing anthocyanin accumulation and ensuring plant cell tolerance. Additionally, transcriptomic analyses will provide insights into gene expression changes induced by naringenin, identifying upregulated and downregulated genes. These findings contribute to a larger-scale project aimed at developing sustainable vineyard practices to resynchronize grape technological and phenolic ripening, thereby mitigating climate change impacts. Vineyard applications will also be conducted using citrus peel extracts obtained through subcritical water treatment, as these preparations are known to contain high levels of naringenin.