Grapevine Priming under Adverse Temperature Stresses

The need to find approaches to reduce the negative impact of temperature stress conditions on vineyards is driven by the increasing frequency of temperature fluctuations and the aggravation of damage. Therefore, the aim of this study was to investigate the effect of priming with physiologically active substances on mitigating freezing stress and the combined stress of drought and high temperature, as well as to identify the physiological basis for priming defense responses. The experiment was conducted on one-year-old vegetative seedlings of ‘Cabernet Sauvignon’ (freezing stress, −1.5°C) and ‘Kurchansky’ (combined drought and high-temperature stress, i.e., lack of irrigation and 40°C), which are sensitive to these types of temperature stress. Treatment of ‘Cabernet Sauvignon’ plants with combinations of methyl jasmonate and proline and salicylic acid and proline under freezing temperature conditions exhibited a protective effect. A reduction in electrolyte leakage in the treated variants indicated stabilization of cytoplasmic membranes and an increase in the adaptive potential of the plants. However, salicylic acid and proline treatment proved to be the most effective, as it was associated with coordinated changes across multiple facets of grape metabolism. Exogenous priming with salicylic acid and proline positively affected the expression of genes involved in abiotic stress protection, chlorophyll content in leaves, viniferin content, and soluble sugar levels, while reducing malondialdehyde content. Priming of ‘Kurchansky’ plants under combined drought and high-temperature conditions had a positive effect on the expression of some important protective genes. Priming also led to an increase in the chlorophyll stability index and soluble sugar content.