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Herein, we investigate the phytogenic synthesis of zinc oxide nanoparticles (ZnO-NPs) by using aqueous extract of seed coat of almond as a novel resource which can acts as a stabilizing and reducing agents. Successful biosynthesis of ZnO-NPs was observed by Ultraviolet-visible spectroscopy (UV-vis) showing peak at ~272 nm. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques confirm the circular shape with an average size of ~20 nm. Applications of ZnO-NPs were observed on carrot (Daucus carota) plant infected with pathogenic fungus Rhizoctonia solani. Spray with 50 ppm and 100 ppm ZnO-NPs caused significant increase in plant growth attributes and photosynthetic pigments of carrot plants. It has been reported that the synthesized ZnO-NPs demonstrated an inhibitory activity against plant pathogenic fungus R. solani and reduces disease in carrot plants. Scanning electron microscopy and confocal microscopy indicated adverse effect of ZnO-NPs on pathogens. Antifungal efficiency of ZnO-NPs was further explained with help of molecular docking analysis. Conformation with highest negative binding energy was used to predict binding site of receptor with NPs to know mechanistic approach. ZnO-NPs are likely to interact with the pathogens by mechanical enfolding which may be one of the major toxicity actions against R. solani by ZnO-NPs. RESEARCH HIGHLIGHTS: ZnO nanoparticles were synthesized using waste material from the coat of almond seeds. Images from SEM, TEM, and related techniques like EDS and SAED revealed the irregularity of the ZnO NPs as well as their atom composition. FTIR and XRD analyses confirmed the formation and the presence of crystalline ZnO NPs in nature. Biogenic ZnONPs were found to be effective against the plant pathogenic fungus R. solani. A spray of 50 ppm and 100 ppm ZnO-NPs significantly increased carrot plant growth characteristics and photosynthetic pigments.

Nanoparticles (NPs) have a critical function in mitigating the disease of fruits and vegetables. In the present investigation, the effects of three levels of concentrations (0.05, 0.10, and 0.20 mg/mL) of titanium dioxide NPs (TiO2-NPs) and silicon dioxide NPs (SiO2-NPs) were investigated against fungus Phomopsis vexans, bacterium Ralstonia solanacearum, and Meloidogyne incognita (root-knot nematode). The present investigation’s findings found that the application of SiO2-NPs was more efficient against test pathogens in comparison to TiO2-NPs. The best result produced by SiO2-NPs against pathogenic strain was used in the molecular docking investigation with the protein of R. solanacearum to better understand the interaction of active amino acids with SiO2-NPs. The obtained results revealed that the administration of 0.20 mg/mL foliar spray of SiO2-NPs in plants with M. incognita improves up to 37.92% of shoot dry weight and increases 70.42% of chlorophyll content. P. vexans growth was suppressed by 41.2% with 0.62 mm of inhibition zone when SiO2-NPs were given at a dosage of 0.20 mg/mL. The reductions in egg hatching and M. incognita (J2) mortality were greater in SiO2-NPs than in TiO2-NPs. The results of scanning electron microscopy confirmed that the application of both NPs harmed test pathogens. The confocal study also showed the penetration of NPs among test pathogens.

The effects of silicon dioxide nanoparticles (SiO2 NPs) in two concentrations (0.10 and 0.20 gL− 1) as foliar spray and seed priming was observed on plant growth attributes, chlorophyll, carotenoid, proline, activities of defense enzymes of tomato and on bacterial pathogens i.e. Pseudomonas syringae pv. tomato (Pst), Xanthomonas campestris pv. vesicatoria (Xcv), Pectobacterium carotovorum subsp. carotovorum (Pcc) and Ralstonia solanacearum (Rs), and fungal pathogens i.e. Fusarium oxysporum f. sp. lycopersici (Fol) and Alternaria solani (As) under in vitro and greenhouse conditions. Disease suppression and increase in plant growth was dependent on concentration of NPs and mode of application. Foliar spray was more effective than seed priming in increasing plant growth, chlorophyll, carotenoid, proline and activities of defense enzymes i.e. superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and phenylalanine ammonia lyase (PAL) in the presence and absence of pathogens. Foliar spray of 0.20 gL− 1SiO2 NPs caused highest increase in plant growth parameters, chlorophyll, carotenoid, proline and activities of defense enzymes in tomato plants and caused maximum reduction in disease indices. In vitro tests and scanning electron microscopy revealed antimicrobial effects of SiO2 NPs with varied adverse effects on pathogens under study. Plants subjected to foliar spray with 0.20 gL− 1SiO2 NPs had more plant growth attributes, chlorophyll, carotenoid, proline and defense enzymes against pathogens under study.

Bacterial and fungal diseases of tomato caused severe yield losses and are important constrains in successful cultivation. Therefore, impact of zinc oxide nanoparticles (ZnO NPs) on growth of tomat...

Diseases of carrot (Daucus carota L.) that cause yield losses include bacterial soft-rot incited by Pectobacterium carotovorum pv. carotovorum (Jones) Waldee; bacterial leaf blight incited ...

The effects of graphene oxide (GO) and zinc oxide (ZnO) nanoparticles (NPs) at two concentrations, i.e., 0.05 mg ml−1 and 0.10 mg ml−1 were observed on Pectobacterium carotovorum, Xanthomonas campestris pv. carotae, Meloidogyne javanica, Alternaria dauci and Fusarium solani on the growth of carrot (Daucus carota). Specific physiological variables studied include chlorophyll, carotenoid and proline contents. Inoculation of plants with P. carotovorum, X. campestris pv. carotae, M. javanica, A. dauci and F. solani reduced plant growth and chlorophyll and carotenoid contents but increased proline contents. Application of GO or ZnO NPs to plants with or without pathogens caused significant increases in plant growth, chlorophyll, carotenoid and proline contents. ZnO NPs were more effective than GO NPs in increasing plant growth, chlorophyll, carotenoid and proline contents. The 0.10 mg ml−1 concentration of both NPs was more effective in increasing plant growth, chlorophyll, carotenoid and proline contents than the 0.05 mg ml−1 concentration. Galling and multiplication of M. javanica was reduced by NPs application. ZnO NPs at concentration, 0.10 mg ml−1 caused highest reduction in galling and nematode multiplication and GO NPs at 0.05 mg ml−1 the least. Soft rot, bacterial leaf blight, leaf spot and root rot indices caused by P. carotovorum, X. campestris pv. carotae, A. dauci and F. solani respectively were 4. Disease indices were reduced to 2 when 0.05 and 0.10 mg ml−1 GO and 0.05 mg ml−1 ZnO were sprayed onto plants with test pathogens. Indices were highly reduced to 1 when 0.10 mg ml−1 ZnO was sprayed onto plants with test pathogens.

Nanoparticles (NPs) have been applied for management of pathogenic microbes affecting agricultural crops. Pectobacterium betavasculorum (Thomson et al., 1984) Gardan et al., 2003, Xanthomon...