Association Between Contrasting Water Regimes and Telomere Length Variation in Field-Grown Grapevines: An Integrated Physiological, Metabolomic and Molecular Approach

Climate change is increasing the exposure of crops to drought stress, highlighting the need for integrative approaches to assess plant responses under field conditions. In this study, telomere length (TL) was evaluated in field-grown grapevine (Vitis vinifera L., cv. Aglianico) subjected to rainfed (RF) and controlled deficit irrigation (CDI) regimes. A qPCR-based protocol was applied together with physiological measurements, UAV-derived vegetation indices, and berry metabolomic profiling to investigate plant responses to different water regimes. Physiological and metabolomic analyses confirmed distinct responses between treatments, with rainfed vines showing more negative leaf water potential, lower stomatal conductance, and increased accumulation of stress-associated metabolites, including anthocyanins and abscisic acid. Linear mixed-effects modeling showed no significant difference in TL between treatments at the beginning of the experimental period (p = 0.198), whereas rainfed vines displayed significantly lower TL values than irrigated vines at the end of the growing season (p = 0.0009). TL decreased significantly over time in both treatments. The treatment × time interaction suggested a greater TL reduction in rainfed vines in the primary model (p = 0.064), and this effect was significant in a complete-pair sensitivity analysis (p = 0.036). These findings indicate an association between irrigation regime and telomere length variation under field conditions. The study provides preliminary evidence supporting the potential application of TL measurements for investigating plant responses to environmental stress in grapevine.