Grapevines (Vitis vinifera L.) face significant challenges from abiotic stresses caused by climate change, including drought, salinity, and temperature extremes. This comprehensive review examined the role of beneficial microorganisms in enhancing grapevine tolerance to these stresses, focusing on arbuscular mycorrhizal fungi (AMF), plant growth-promoting rhizobacteria (PGPR), and endophytes. The study analyzes species-specific effects and their molecular mechanisms, highlighting how single and consortium inoculations improve plant resilience. AMF species, particularly Funneliformis mosseae and Rhizophagus irregularis, demonstrated significant enhancement in drought and salinity tolerance through improved nutrient uptake and stress response modulation. The PGPRs, Bacillus and Pseudomonas species, show remarkable abilities to mitigate various abiotic stresses through mechanisms including phytohormone production and antioxidant defense enhancement. Endophytic microorganisms such as Pseudomonas fluorescens RG11 and Serendipita indica play crucial roles in stress mitigation through melatonin production and improved water retention, respectively. The synergistic effects of combined AMF, PGPR, and PGPF applications led to a significant increase in grapevine drought and salinity tolerance, improving nutrient uptake, photosynthesis rates, and antioxidant defense mechanisms. Molecular analysis revealed that these microbial consortia regulate the expression of stress-responsive genes, particularly VvNCED and VvP5CS, enhancing grapevine resilience through improved osmotic adjustment, ROS scavenging, and hormonal regulation. These findings provide valuable insights into the molecular pathways underlying stress tolerance, offering promising strategies for sustainable viticulture under climate change.

Rootstocks serve as a strategic tool for grapevine adaptation to specific biotic and abiotic conditions and for managing vine growth, grape yield, and berry composition in commercial vineyards. This study investigates the influences of four different rootstock varieties (101-14 MGt, 3309 C, 110 R, and 140 Ru) on the viticultural performance of ‘Xinomavro’ vines, a prominent Greek red winegrape varietal. By conducting a two-year field experiment using various rootstocks, we assessed parameters related to water status, vegetative growth, yield, and berry composition. Our results revealed that rootstock selection has a significant impact on vine development, especially in terms of berry size and the concentrations of secondary metabolites. Principal component analysis confirmed the complex interaction between rootstock vigor and vine productivity. This study underscores the importance of rootstock variety in manipulating grapevine characteristics, particularly for the ‘Xinomavro’ variety, in response to regional climatic conditions.

Our objective was to investigate the effect of water and nitrogen (N) availability on the carbon isotope composition of leaf blades, canes and ripe berry must (juice) in field grown grapevines.In two consecutive years, the combination of two irrigation treatments [Irrigation (I): 70 % of crop evapotranspiration (ETc) and no irrigation (NI)] and three rates of ammonium nitrate [0 (N0), 60 (N60) and 120 (N120) kg/ha N] were applied to two separate vineyards planted with cv. Xinomavro and cv. Cabernet-Sauvignon respectively in a randomised complete block design. Carbon isotope composition (δ13C) of leaf blades, stem water potential (Ψs), and leaf gas exchange were measured at berry set, bunch closure, veraison and maturity during each growing season. δ13C of bulk berry must at maturity and of dormant canes was also measured.Leaf δ13C and cane δ13C decreased with water supply, but increased with N fertilisation. Must δ13C was lower in the irrigated N0 and N60 vines, whereas irrigation treatments did not differ under the N120 rate. The relative weight of irrigation and fertilisation effect on leaf δ13C varied across samplings: N application accounted for a higher proportion of leaf δ13C variance during the early stages of berry growth, whereas irrigation induced higher variance of leaf δ13C after veraison. The weight of the irrigation effect on cane δ13C was higher from that of fertilisation.Discrimination mechanisms against 13C in grapevine could be mediated by both N fertilisation and irrigation. The well-documented explanation of δ13C variation based on isotopic effects during CO2 diffusion through leaf stomata and carboxylation driven by water conditions may not apply to all cases, since additional discriminating processes against 13C associated with CO2 transfer from the intercellular spaces to the carboxylation sites may be affected by nitrogen supply.The study provides evidence for the first time that carbon isotope composition of leaf blades, canes and berry must is modulated by nitrogen supply. Interpretations of carbon isotope natural abundance in field grown grapevine tissues should therefore consider both water and nitrogen availability.

A three-year study was conducted to investigate the effects of two timings—at berry set and at veraison—of post-bloom leaf removal (LR) applications from the basal sections of the shoot on the growth, yield, and berry composition of Vitis vinifera L. cv. Xinomavro, the major red winegrape of North Greece. LR at berry set drastically reduced yield by affecting all its components while increasing the ratio of secondary foliage per total leaf area. LR at veraison had a milder effect on growth and yield. Both treatments increased sugar and phenolic compound levels in berries, while early LR increased the contribution of more stable forms of anthocyanins. Additionally, early LR increased the skin-to-pulp ratio, suggesting that it could be an effective viticultural technique for more concentrated red wines. Overall, both LR timings improved most of the berry attributes compared to the non-treated vines; however, the earlier application can be recommended when aiming at the production of deep-colored and richly flavored wines.