Natalia Naraikina

It is of utmost importance to investigate the effect of carbon-based nanostructures on plants in order to fully unlock their potential for enhancing productivity and stress tolerance. In this study, a comprehensive assessment of the effect of pre-sowing treatment of wheat seeds with fullerenol (PHF [C₆₀(OH)₂₄], 0.1 mg/L) solution on a number of physiological and biochemical parameters in seedlings under optimal and low temperature (LT, 4 °C, 5 days) conditions was carried out. Seedlings primed with PHF differed from control variant in accelerated growth (by 27–34%), increased biomass (by 10%), larger area of chloroplasts and mesophyll cells (by 40%), more intensive photosynthesis (1.5-fold higher), increased content of chlorophyll a (by 11%), proteins (by 28%) and ascorbic acid, reduced level of MDA and H₂O₂, decreased SOD activity (by 45%) and a higher level of COR-genes (WCOR15, WCOR726) transcription (p < 0.05). Under LT conditions, PHF nanopriming enhanced photosynthesis intensity by increasing chloroplast area, content of chlorophyll b (by 22%) and proportion of chlorophyll in LHC (by 11%), as well as increasing the expression of RBCS (fourfold higher), content of proline, and COR-gene expression (p < 0.05). All these changes are adaptive and expand the adaptive potential of plants. It is concluded that nanopriming with PHF is an active metabolic modulator that reduces ROS generation and enhances cold acclimation of wheat.

Nanopriming is a unique way to change the metabolism and stress tolerance of plants. In this study, the effects of seed priming with gold nanoparticles (Au-NPs, 15 nm) on the photosynthetic apparatus, pro-/antioxidant balance, and cold tolerance of tomato (Solanum lycopersicum L.) were examined for the first time. The study revealed that nanopriming with Au-NPs (20 µg mL⁻¹ for 24 h) causes an increase in cold tolerance both under control conditions and after cold adaptation at 9 °C for 5 d. In additional, nanopriming leads to the formation of tomato plants with altered photosynthetic apparatus and pro-/antioxidant status. At the same time, nanoparticles do not accumulate in the aboveground parts of the plants. Under control conditions, nanopriming enhances photosynthesis rate, the relative expression of rbcS gene, the number of grana in chloroplast, and the content of photosynthetic pigments in leaves. Regardless of the temperature (in control conditions and during cold adaptation), nanopriming increases the size of chloroplast, the relative expression of rbcL gene, the content of malonic dialdehyde and H₂O₂, and the activity of catalase and superoxide dismutase in leaves. Nanopriming decreases the activity of ascorbate peroxidase and sugar content in tomato leaves and leads to a number of structural changes in chloroplasts. This study highlights the potential of the use of Au-NPs as a promising strategy to mitigate cold stress in tomato plants by affecting photosynthesis and the antioxidant system.

Proteomic profiling using ultrafast chromatography–mass spectrometry provides valuable insights into plant responses to abiotic factors by linking molecular changes with physiological outcomes. Nanopriming, a novel approach involving the treatment of seeds with nanoparticles, has demonstrated potential for enhancing plant metabolism and productivity. However, the molecular mechanisms underlying nanoparticle-induced effects remain poorly understood. In this study, we investigated the impact of gold nanoparticle (Au-NP) seed priming on the proteome of wheat (Triticum aestivum L.) seedlings. Differentially regulated proteins (DRPs) were identified, revealing a pronounced reorganization of the photosynthetic apparatus (PSA). Both the light-dependent reactions and the Calvin cycle were affected, with significant upregulation of chloroplast-associated protein complexes, including PsbC (CP43), chlorophyll a/b-binding proteins, Photosystem I subunits (PsaA and PsaB), and the γ-subunit of ATP synthase. The large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCo) exhibited over a threefold increase in expression in Au-NP-treated seedlings. The proteomic changes in the large subunit RuBisCo L were corroborated by transcriptomic data. Importantly, the proteomic changes were supported by physiological and biochemical analyses, ultrastructural modifications in chloroplasts, and increased photosynthetic activity. Our findings suggest that Au-NP nanopriming triggers coordinated molecular responses, enhancing the functional activity of the PSA. Identified DRPs may serve as potential biomarkers for further elucidation of nanopriming mechanisms and for the development of precision strategies to improve crop productivity.

The study of cold-tolerance mechanisms of wheat as a leading cereal crop is very relevant to science. Primary metabolites play an important role in the formation of increased cold tolerance. The aim of this research is to define changes in the content of primary metabolites (soluble proteins and sugars), growth, and photosynthetic apparatus of freezing-tolerant and cold-sustainable wheat (Triticum aestivum L.) genotypes under optimal conditions and after prolonged (7 days) exposure to low temperature (4 °C). In order to gain a deeper comprehension of the mechanisms behind wheat genotypes’ adaptation to cold, we determined the expression levels of photosynthetic genes (RbcS, RbcL) and genes encoding cold-regulated proteins (Wcor726, CBF14). The results indicated different cold-adaptation strategies of freezing-tolerant and cold-sustainable wheat genotypes, with soluble proteins and sugars playing a significant role in this process. In plants of freezing-tolerant genotypes, the strategy of adaptation to low temperature was aimed at increasing the content of soluble proteins and modification of carbohydrate metabolism. The accumulation of sugars was not observed in wheat of cold-sustainable genotypes during chilling, but a high content of soluble proteins was maintained both under optimal conditions and after cold exposure. The adaptation strategies of wheat genotypes differing in cold tolerance were related to the expression of photosynthetic genes and genes encoding cold-regulated proteins. The data improve our knowledge of physiological and biochemical mechanisms of wheat cold adaptation.