Heat-stress responses regulated via a MYB24-MYC2 complex

L’A.O.C. Coteaux du Languedoc est située dans le Sud de la France, dans la partie Ouest de la bordure méditerranéenne. Elle forme un vaste amphithéâtre largement ouvert sur la mer méditerranée. L’Appellation a été constituée en 1960 par le regroupement de 14 anciennes petites appellations d’origine représentant 55 communes éparpillées dans les départements de l’Aude, de l’Hérault et du Gard. Par la suite, plusieurs extensions successives ont conduit à un ensemble actuellement composé de 168 communes.

Vines are exposed to environmental conditions that cause abiotic stress on the plants (drought, nutrient and mineral deficits, salinity, etc.). Polyamines are growth regulators involved in various physiological processes, as in abiotic plant stress responses. Stressful conditions can modify grape’s composition, and in this work, we have focused on studying the effect of abiotic stress on the composition of polyamines and amino acids in grapes. In addition, the effect of grape variety on these compounds has been studied.

Nitrogen (N) uptake by grapevine roots in forms like nitrate, ammonium, urea, or amino acids influences vegetative and generative growth, impacting grape quality and wine sensory profile. The study examined nitrogen’s influence on phenolic compounds in leaves, berries, and wine across different scales — hydroponics, soil culture, and vineyard trials. Nitrogen forms altered metabolite patterns in leaves and wine significantly, affecting aroma and flavor. Key nitrogen assimilation enzymes (NR, NiR, GS) in grapevine rootstocks responded to nitrogen forms and timing. Hydroponically grown rootstocks fertilized with various forms showed differences in enzyme expression and activity, suggesting rootstocks can assimilate amino acid glutamine (Gln).

Introduction: Malolactic fermentation (MLF) is a common process in winemaking to reduce wine acidity, maintain microbial stability and modify wine aroma. However, successful MLF is often hampered by their sluggish or stuck activity of malolactic bacteria (MLB) which may be caused by nutrient deficiency, especially when MLB are inoculated after alcoholic fermentation (Alexandre et al., 2004; Lerm et al., 2010). Identification and characterization of essential nutrients and growth factors for MLB allows for production of highly efficient nutrient supplements for MLF.

The hot and dry climate of the Demarcated Region of Douro (DRD), Portugal, particularly during the summer, induces soil water deficits that influence the growth and development of grapevines.