Drought, salinity, heavy metal contamination and temperature fluctuations are increasingly constraining crop production. Conventional agronomic and chemical approaches alone often fail to ensure stable yields under these abiotic stresses. Nanomaterials are emerging as complementary tools for improving stress tolerance and helping to stabilize yield because they can interact efficiently with key processes at the rhizosphere, at the leaf surface and within cells. Their high surface area, tunable surface chemistry and functionalization, and controlled-release properties make them suitable for root application, foliar spraying, and seed treatment. These features enable low-dose, efficient, and targeted delivery. This review delineates five mechanistic dimensions: restoring redox homeostasis; enhancing nutrient uptake and maintaining ion balance; modulating signaling factors and hormone levels; influencing gene expression; and improving structural and physiological traits at the root and chloroplast levels. Based on case studies under salinity, drought, and heavy metal conditions, we summarize material- and route-dependent differences in efficacy and define dose boundaries. Moreover, the current limitations arising from limited field evidence and nonuniform evaluation standards are also highlighted. Accordingly, we outline key considerations for material design and application assessment, underscoring the value of this review in integrating mechanisms and guiding the practical translation of nanomaterials for stress alleviation in plants.

The bacterial microbial community composition during wine fermentation is a key contributor to wine quality and flavor. However, studies on the regulatory effects of different grape varieties and co-fermentation processes on the microbial community structure and their synergistic mechanisms remain limited. In this study, Cabernet Sauvignon (CS) was subjected to single-variety fermentation and used as the base wine for co-fermentation with three other grape varieties—Marselan (CSMN), Merlot (CSMT), and Cabernet Gernischt (CSCG)—to systematically compare the differences in the microbial community composition and their effects on the production of metabolic compounds. The results showed that, compared with single-variety fermentation, co-fermentation significantly increased the α-diversity of microbial communities (the Shannon index increased) and exhibited significant differences in β-diversity (PERMANOVA analysis, R² = 0.421, p < 0.001). A neutral model analysis indicated that co-fermentation had a significant impact on microbial community assembly mechanisms, with the contribution of neutral processes to community assembly increasing from 45.5% (in the CSCG process) to 62.3% (in the CSMT process). A microbial co-occurrence network analysis revealed that co-fermentation enhanced the network complexity of microbial communities and strengthened the synergistic interactions between microbial taxa. A metabolic compound analysis revealed that co-fermentation significantly enhanced the production of key aroma compounds, resulting in increased concentrations of isoamyl acetate, ethyl hexanoate, linalool, and geraniol. These findings highlight the differences in microbial communities and their synergistic mechanisms among co-fermented grape varieties, providing theoretical guidance and practical insights for optimizing co-fermentation processes and improving wine quality.