TABLE 3.
Effect of ZnO NPs in ameliorating biotic stress in plants.
| Disease/Pathogen | Plant | Concentration and mode of application of ZnO NPs | Synthesis method of ZnO NPs | Mechanism of mitigating disease | References |
|---|---|---|---|---|---|
| Downy Mildew (Sclerospora graminicola) | Pearl Millet | 50 ppm | Aqueous extract of Eclipta alba | Plasmolysis and inhibition of spore germination. Enhanced activity of defense enzymes like PPO, POX, PAL and LOX | Nandhini et al. (2019) |
| Meloidogyne incognita, Rhizoctonia solani, Pectobacterium betavasculorum | Beet root | 200 mg/L (Seed priming and Foliar spray) | Commercial available ZnO NPs from Sigma-Aldrich | Reduced nematode multiplication and root galling. Increased level of SOD, CAT, PAL and PPO | Khan and Siddiqui (2021) |
| Tobacco Mosaic virus- | Tomato | 100 μg/mL (Foliar spray) | Aqueous leaf extract of Mentha spicata | 90.21% reduction in viral accumulation. Upregulated activity of PR-1, PAL, CHS and POD | Abdelkhalek and Al- Askar (2020) |
| Tobacco Mosaic virus | Tomato | 50 mg/L and 100 mg/L | - | Increased activity of CAT, SOD, POX, APX, GR, LOX, CA, NR, AsA and GSH | Sofy et al. (2021) |
| Bacterial and fungal pathogens | Tomato | 0.20 mL-1 (Seed priming and Foliar spray) | Commercial available ZnO NPs from Sigma-Aldrich | Improved plant growth (27.8%–35.8% increase in shoot dry weight), total chlorophyll, carotenoids and proline content | Parveen and Siddiqui (2021) |
| Ralstonia solanacearum | Tomato | 0, 1, 4, and 8% | Flower extract of Matricaria chamomilla | Decreased bacterial population in the soil. Increased shoot, root length, and fresh biomass of the treated plant | Khan et al. (2021a) |
| Wilt disease (Fusarium oxysporum) | Pepper | - | Chemically prepared ZnO hydrogel | Increased the chlorophyll, carotenoid, soluble sugars, proteins, proline content and activity of POX and PPO | Abdelaziz et al. (2021) |
| Wilt disease (Fusarium oxtysporum) | Egg plant | - | Penicillium expansum fungal filtrate extract | Reduced disease incidence. Improved plant height, root length, plant fresh biomass, chlorophyll a, chlorophyll b, total soluble protein and phenol content | Abdelaziz et al. (2022) |
| Wilt disease (Fusarium oxysporum) | Chickpea | Seed priming | Mycosynthesis (by using Trichoderma harzianum as a reducing and stabilizing agent) | Reduced the disease incidence by 90%. Increased the content of sugars, phenol, flavonoids and total proteins and activity of SOD, POD and CAT antioxidants were also enhanced | Farhana et al. (2022) |
| Wilt disease (Fusarium oxysporum) | Cherry tomato | 3,000 ppm (Foliar spray) | Commercial available ZnO NPs from Nano-Gate Company, Cairo, Egypt | 92.6% reduction in the disease severity. Enhanced Mn, Zn, Fe, chlorophyll content, and PAL enzyme activity | Shams et al. (2023) |
| Blast fungus (Magnaporthe oryzae) | Rice | 10, 20, 30, and 40 mg/L (Foliar spray) | Commercial available ZnO NPs from Sigma Alderich | Decreased the lesion numbers, sporulation intensity, MDA and H2O2 level. Improved total chlorophyll and activity of SOD, PAL, POX, and CAT antioxidants | Mazhar et al. (2023) |