A comparative study of two grapevine rootstocks with contrasting drought stress responses revealed that the drought-resilient RUG harbors an efficient antioxidant defense system, characterized by increased activities of superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT), along with elevated proline (Pro) levels compared to the drought-sensitive MGT. This robust scavenging machinery enables RUG to maintain redox balance, effectively mitigating oxidative stress and preserving cellular integrity during drought. Anatomical evaluations showed severe xylem disruptions in MGT, including extensive tylosis, leading to leaf necrosis and impaired water transport. Conversely, RUG maintained a structurally intact and functional xylem, crucial for sustaining hydraulic conductivity and water supply during drought. The pronounced rise in Pro underscores its critical role in drought resilience, working synergistically with other cellular components to facilitate osmotic adjustment while detoxifying reactive oxygen species (ROS) and minimizing oxidative damage. Transcriptome profiling suggested that RUG displays sequential gene expression during drought driven by distinct molecular processes for photosynthesis, osmotic adjustment, and structural remodeling, a dynamic notably absent in MGT. These findings emphasize the complex interplay of osmotic and oxidative homeostasis in RUG, illustrating the adaptive mechanisms that contribute to its drought resilience, potentially guiding future rootstock selection and breeding strategies.

Like other plant stresses, salinity is a central agricultural problem, mainly in arid or semi-arid regions. Therefore, salt-adapted plants have evolved several adaptation strategies to counteract salt-related events, such as photosynthesis inhibition, metabolic toxicity, and reactive oxygen species (ROS) formation. European grapes are usually grafted onto salt-tolerant rootstocks as a cultivation practice to alleviate salinity-dependent damage. In the current study, two grape rootstocks, 140 Ruggeri (RUG) and Millardet et de Grasset 420A (MGT), were utilized to evaluate the diversity of their salinity adaptation strategies. The results showed that RUG is able to maintain higher levels of the photosynthetic pigments (Chl-T, Chl-a, and Chl-b) under salt stress, and hence accumulates higher levels of total soluble sugars (TSS), monosaccharides, and disaccharides compared with the MGT rootstock. Moreover, it was revealed that the RUG rootstock maintains and/or increases the enzymatic activities of catalase, GPX, and SOD under salinity, giving it a more efficient ROS detoxification machinery under stress.

Salinity is one of the substantial threats to plant productivity and could be escorted by other stresses such as heat and drought. It impairs critical biological processes, such as photosynthesis, energy, and water/nutrient acquisition, ultimately leading to cell death when stress intensity becomes uncured. Therefore, plants deploy several proper processes to overcome such hostile circumstances. Grapevine is one of the most important crops worldwide that is relatively salt-tolerant and preferentially cultivated in hot and semi-arid areas. One of the most applicable strategies for sustainable viticulture is using salt-tolerant rootstock such as Ruggeri (RUG). The rootstock showed efficient capacity of photosynthesis, ROS detoxification, and carbohydrate accumulation under salinity. The current study utilized the transcriptome profiling approach to identify the molecular events of RUG throughout a regime of salt stress followed by a recovery procedure. The data showed progressive changes in the transcriptome profiling throughout salinity, underpinning the involvement of a large number of genes in transcriptional reprogramming during stress. Our results established a considerable enrichment of the biological process GO-terms related to salinity adaptation, such as signaling, hormones, photosynthesis, carbohydrates, and ROS homeostasis. Among the battery of molecular/cellular responses launched upon salinity, ROS homeostasis plays the central role of salt adaptation.