Selenium nanoparticles (SeNPs) have advantages over other nanomaterials because of the promising role of selenium in the stabilization of the immune system and activation of the defense response. The use of SeNPs and their supplements not only have pharmacological significance but also boost and prepare the body’s immune system to fight the pathogens. This review summarizes the recent progress in the biogenesis of plant-based SeNPs by using various plant species and the role of secondary metabolites on their biocompatible functioning. Phyto-synthesis of SeNPs results in the synthesis of nanomaterials of various, size, shape and biochemical nature and has advantages over other routine physical and chemical methods because of their biocompatibility, eco-friendly nature and in vivo actions. Unfortunately, the plant-based SeNPs failed to attain considerable attention in the pharmaceutical industry. However, a few studies were performed to explore the therapeutic potential of the SeNPs against various cancer cells, microbial pathogens, viral infections, hepatoprotective actions, diabetic management, and antioxidant approaches. Further, some of the selenium-based drug delivery systems are developed by engineering the SeNPs with the functional ligands to deliver drugs to the targeted sites. This review also provides up-to-date information on the mechanistic actions that the SeNPs adopt to achieve their designated tasks as it may help to develop precision medicine with customized treatment and healthcare for the ailing population.

The present study was aimed to biosynthesize selenium nanoparticles (SeNPs) and assess their foliar applications to improve the growth of wheat plants under controlled irrigation and drought stress. Bud aqueous extract of Allium sativum L. was used as a reducing and stabilizing agent of SeNPs followed by their optical and morphological characterization by using ultraviolet-visible spectroscopy, scanning electron microscopy, Fourier-transform infrared, and energy dispersive X-ray analysis. Various concentrations of SeNPs (10, 20, 30, and 40 mg/L) were applied exogenously to drought-tolerant (V1) and drought-susceptible (V2) wheat varieties at the trifoliate stage. Under the positive control conditions, plants were irrigated with 450 mL of water/pot (100% field capacity); and under water-deficit environment, plants were irrigated with 160 mL of water/pot (35% field capacity). Remarkable increase in plant height, shoot length, shoot fresh weight, shoot dry weight, root length, root fresh weight, root dry weight, leaf area, leaf number, and leaf length has been observed when 30 mg/L concentration of SeNPs was used. However, the plant morphological parameters decreased gradually at higher concentrations (40 mg/L) in both selected wheat varieties. Therefore, 30 mg/L concentration of SeNPs was found most preferable to enhance the growth of selected wheat varieties under normal and water-deficient conditions.

The current study involves the biogenesis of titanium dioxide nanoparticles (TiO₂ NPs) by using Moringa oleifera Lam. aqueous leaf extract for the reduction of titanium dioxide salt into TiO₂ nanoparticles. The biosynthesized TiO₂ nanoparticles were observed by using the UV-visible spectrophotometry, SEM, EDX and XRD analytical methods. It was confirmed that the nanoparticles are crystalline and exist in the size range of 10–100 nm. The FTIR analysis confirmed the presence of O-H (hydrogen bonding), N-H (amide), C-C (alkanes) and C-I (Iodo-stretch) functional groups responsible for the stabilization of nanoparticles. Various concentrations (20, 40, 60 and 80 mg/L) of TiO₂ NPs were applied exogenously on wheat plants infected with a fungus Bipolaris sorokiniana responsible to cause spot blotch disease at different time intervals. The measurement of disease incidence and percent disease index showed the time-dependent response and 40 mg/L was reported a stable concentration of TiO₂ NPs to reduce the disease severity. The effects of biosynthesized TiO₂ NPs were also evaluated for agro-morphological (leaf and root surface area, plant fresh and dry weight and yield parameters), physiological (relative water content, membrane stability index and chlorophyll content) and non-enzymatic metabolites (soluble sugar, protein, soluble phenol and flavonoid content) in wheat plants under biotic stress and 40 mg/L concentration of TiO₂ NPs was found to be effective to elicit modifications to reduce biotic stress. The current study highlights the significant role of biosynthesized TiO₂ NPs in controlling fungal diseases of wheat plants and thus ultimately improving the quality and yield of wheat plants.

Drought adversely affects the yield, quality and nutritional value of the crop plants. Additionally, it causes unrest in society and economic loss to the farmers and governments. The present study involved the applications of nanoparticles to induce drought tolerance and improve yield in the wheat ( Triticum aestivum L.) plants. Green chemical methods were used for the synthesis of silver nanoparticles (AgNPs) and copper nanoparticles (CuNPs). CuNPs were used in 0, 3, 5 and 7 mg/L and 0, 10, 20 and 30 mg/L of AgNPs were tested at −4, −6 and −8 bars osmotic potential in laboratory experiments and 40%, 60% and 80% field capacity (FC) in the glasshouse experiments were maintained. The solution culture experiments revealed significantly higher chlorophyll stability index (CSI), leaf succulence (LS) and leaf K (LK) content in plants treated with 03 mg/L of CuNPs and 10 mg/L of AgNPs, indicated the positive role of CuNPs and AgNPs in drought tolerance of wheat. A similar trend was observed for stomatal conductance (SC) and morphological parameters with the applications of Cu and Ag nanoparticles at different levels of field capacity. The results of this study provide the experimental evidence to use CuNPs and AgNPs to induce drought resistance and improve yield in the wheat plants by a satisfactory increase in nutrients uptake and water retention.