Time-Dependent and Coating Modulation of Tomato Response upon Sulfur Nanoparticle Internalization and Assimilation: An Orthogonal Mechanistic Investigation.

Nanoenabled strategies have recently attracted attention as a sustainable platform for agricultural applications. Here, we present a mechanistic understanding of nanobiointeraction through an orthogonal investigation. Pristine (nS) and stearic acid surface-modified (cS) sulfur nanoparticles (NPs) as a multifunctional nanofertilizer were applied to tomato (Solanum lycopersicumL.) through soil. Both nS and cS increased root mass by 73% and 81% and increased shoot weight by 35% and 50%, respectively, compared to the untreated controls. Bulk sulfur (bS) and ionic sulfate (iS) had no such stimulatory effect. Notably, surface modification of S NPs had a positive impact, as cS yielded 38% and 51% greater shoot weight compared to nS at 100 and 200 mg/L, respectively. Moreover, nS and cS significantly improved leaf photosynthesis by promoting the linear electron flow, quantum yield of photosystem II, and relative chlorophyll content. The time-dependent gene expression related to two S bioassimilation and signaling pathways showed a specific role of NP surface physicochemical properties. Additionally, a time-dependent Global Test and machine learning strategy applied to understand the NP surface modification domain metabolomic profiling showed that cS increased the contents of IA, tryptophan, tomatidine, and scopoletin in plant leaves compared to the other treatments. These findings provide critical mechanistic insights into the use of nanoscale sulfur as a multifunctional soil amendment to enhance plant performance as part of nanoenabled agriculture.

Nanoscale CuO charge and morphology control Fusarium suppression and nutrient biofortification in field-grown tomato and watermelon.

Limited data exist on how surface charge and morphology impact the effectiveness of nanoscale copper oxide (CuO) as an agricultural amendment under field conditions. This study investigated the impact of these factors on tomatoes and watermelons following foliar treatment with CuO nanosheets (NS-) or nanospikes (NP+ and NP-) exhibiting positive or negative surface charge. Results showed plant species-dependent benefits. Notably, tomatoes infected with Fusarium oxysporum had significantly reduced disease progression when treated with NS-. Watermelons benefited similarly from NP+. Although disease suppression was significant and trends indicated increased yield, the yield effects weren't statistically significant. However, several nanoscale treatments significantly enhanced the fruit's nutritional value, and this nano-enabled biofortification was a function of particle charge and morphology. Negatively charged nanospikes significantly increased the Fe content of healthy watermelon and tomato (20-28 %) and Ca in healthy tomato (66 %), compared to their positively charged counterpart. Negatively charged nanospikes also outperformed negatively charged nanosheets, leading to significant increases in the content of S and Mg in infected watermelon (37-38 %), Fe in healthy watermelon (58 %), and Ca (42 %) in healthy tomato. These findings highlight the potential of tuning nanoscale CuO chemistry for disease suppression and enhanced food quality under field conditions.

Lanthanum Silicate Nanomaterials Enhance Sheath Blight Resistance in Rice: Mechanisms of Action and Soil Health Evaluation.

In the current study, foliar spray with lanthanum (La) based nanomaterials (La10Si6O27 nanorods, La10Si6O27 nanoparticle, La(OH)3 nanorods, and La2O3 nanoparticle) suppressed the occurrence of sheath blight (Rhizoctonia solani) in rice. The beneficial effects were morphology-, composition-, and concentration-dependent. Foliar application of La10Si6O27 nanorods (100 mg/L) yielded the greatest disease suppression, significantly decreasing the disease severity by 62.4% compared with infected controls; this level of control was 2.7-fold greater than the commercially available pesticide (Thifluzamide). The order of efficacy was as follows: La10Si6O27 nanorods > La10Si6O27 nanoparticle > La(OH)3 nanorods > La2O3 nanoparticle. Mechanistically, (1) La10Si6O27 nanorods had greater bioavailability, slower dissolution, and simultaneous Si nutrient benefits; (2) transcriptomic and metabolomic analyses revealed that La10Si6O27 nanorods simultaneously strengthened rice systemic acquired resistance, physical barrier formation, and antioxidative systems. Additionally, La10Si6O27 nanorods improved rice yield by 35.4% and promoted the nutritional quality of the seeds as compared with the Thifluzamide treatment. A two-year La10Si6O27 nanorod exposure had no effect on soil health based on the evaluated chemical, physical, and biological soil properties. These findings demonstrate that La based nanomaterials can serve as an effective and sustainable strategy to safeguard crops and highlight the importance of nanomaterial composition and morphology in terms of optimizing benefit.

Biologically synthesized zinc and copper oxide nanoparticles using Cannabis sativa L. enhance soybean (Glycine max) defense against fusarium virguliforme.

In this study, zinc and copper oxide nanoparticles (NPs) were synthesized using hemp (Cannabis sativa L.) leaves (ZnONP-HL and CuONP-HL), and their antifungal potential was assessed against Fusarium virguliforme in soybean (Glycine max L.). Hemp was selected because it is known to contain large quantities of secondary metabolites that can potentially enhance the reactivity of NPs through surface property modification. Synthesizing NPs with biologically derived materials allows to avoid the use of harsh and expensive synthetic reducing and capping agents. The ZnONP-HL and CuONP-HL showed average grain/crystallite size of 13.51 nm and 7.36 nm, respectively. The biologically synthesized NPs compared well with their chemically synthesized counterparts (ZnONP chem, and CuONP chem; 18.75 nm and 10.05 nm, respectively), confirming the stabilizing role of hemp-derived biomolecules. Analysis of the hemp leaf extract and functional groups that were associated with ZnONP-HL and CuONP-HL confirmed the presence of terpenes, flavonoids, and phenolic compounds. Biosynthesized NPs were applied on soybeans as bio-nano-fungicides against F. virguliforme via foliar treatments. ZnONP-HL and CuONP-HL at 200 µg/mL significantly (p < 0.05) increased (∼ 50%) soybean growth, compared to diseased controls. The NPs improved the nutrient (e.g., K, Ca, P) content and enhanced photosynthetic indicators of the plants by 100-200%. A 300% increase in the expression of soybean pathogenesis related GmPR genes encoding antifungal and defense proteins confirmed that the biosynthesized NPs enhanced disease resistance against the fungal phytopathogen. The findings from this study provide novel evidence of systemic suppression of fungal disease by nanobiopesticides, via promoting plant defense mechanisms.

Aloe Vera Extract Gel-Biosynthesized Selenium Nanoparticles Enhance Disease Resistance in Lettuce by Modulating the Metabolite Profile and Bacterial Endophytes Composition.

The use of nanotechnology to suppress crop diseases has attracted significant attention in agriculture. The present study investigated the antifungal mechanism by which aloe vera extract gel-biosynthesized (AVGE) selenium nanoparticles (Se NPs) suppressed Fusarium-induced wilt disease in lettuce (Lactuca sativa). AVGE Se NPs were synthesized by utilizing sodium selenite as a Se source and AVGE as a biocompatible capping and reducing agent. Over 21 d, 2.75% of total AVGE Se NPs was dissolved into Se ions, which was more than 8-fold greater than that of bare Se NPs (0.34%). Upon exposure to soil applied AVGE Se NPs at 50 mg/kg, fresh shoot biomass was significantly increased by 61.6 and 27.8% over the infected control and bare Se NPs, respectively. As compared to the infected control, the shoot levels of citrate, isocitrate, succinate, malate, and 2-oxo-glutarate were significantly upregulated by 0.5-3-fold as affected by both Se NPs. In addition, AVGE Se NPs significantly increased the shoot level of khelmarin D, a type of coumarin, by 4.40- and 0.71-fold over infected controls and bare Se NPs, respectively. Additionally, AVGE Se NPs showed greater upregulation of jasmonic acid and downregulation of abscisic acid content relative to bare Se NPs in diseased shoots. Moreover, the diversity of bacterial endophytes was significantly increased by AVGE Se NPs, with the values of Shannon index 40.2 and 9.16% greater over the infected control and bare Se NPs. Collectively, these findings highlight the significant potential of AVGE Se NPs as an effective and biocompatible strategy for nanoenabled sustainable crop protection.

Nanomaterial Size and Surface Modification Mediate Disease Resistance Activation in Cucumber (Cucumis sativus).

Crop disease represents a serious and increasing threat to global food security. Lanthanum oxide nanomaterials (La2O3 NMs) with different sizes (10 and 20 nm) and surface modifications (citrate, polyvinylpyrrolidone [PVP], and poly(ethylene glycol)) were investigated for their control of the fungal pathogen Fusarium oxysporum (Schl.) f. sp cucumerinum Owen on six-week-old cucumber (Cucumis sativus) in soil. Seed treatment and foliar application of the La2O3 NMs at 20-200 mg/kg (mg/L) significantly suppressed cucumber wilt (decreased by 12.50-52.11%), although the disease control efficacy was concentration-, size-, and surface modification-dependent. The best pathogen control was achieved by foliar application of 200 mg/L PVP-coated La2O3 NMs (10 nm); disease severity was decreased by 67.6%, and fresh shoot biomass was increased by 49.9% as compared with pathogen-infected control. Importantly, disease control efficacy was 1.97- and 3.61-fold greater than that of La2O3 bulk particles and a commercial fungicide (Hymexazol), respectively. Additionally, La2O3 NMs application enhanced cucumber yield by 350-461%, increased fruit total amino acids by 295-344%, and improved fruit vitamin content by 65-169% as compared with infected controls. Transcriptomic and metabolomic analyses revealed that La2O3 NMs: (1) interacted with calmodulin, subsequently activating salicylic acid-dependent systemic acquired resistance; (2) increased the activity and expression of antioxidant and related genes, thereby alleviating pathogen-induced oxidative stress; and (3) directly inhibited in vivo pathogen growth. The findings highlight the significant potential of La2O3 NMs for suppressing plant disease in sustainable agriculture.

Surface Coated Sulfur Nanoparticles Suppress Fusarium Disease in Field Grown Tomato: Increased Yield and Nutrient Biofortification.

Little is known about the effect of nano sulfur (NS) under field conditions as a multifunctional agricultural amendment. Pristine and surface coated NS (CS) were amended in soil at 200 mg/kg that was planted with tomato (Solanum lycopersicum) and infested with Fusarium oxysporum f. sp. lycopersici. Foliar exposure of CS (200 µg/mL) was also included. In healthy plants, CS increased tomato marketable yield up to 3.3∼3.4-fold compared to controls. In infested treatments, CS significantly reduced disease severity compared to the other treatments. Foliar and soil treatment with CS increased yield by 107 and 192% over diseased controls, respectively, and significantly increased fruit Ca, Cu, Fe, and Mg contents. A $33/acre investment in CS led to an increase in marketable yield from 4920 to 11,980 kg/acre for healthy plants and from 1135 to 2180 kg/acre for infested plants, demonstrating the significant potential of this nanoenabled strategy to increase food production.

Therapeutic Delivery of Nanoscale Sulfur to Suppress Disease in Tomatoes: In Vitro Imaging and Orthogonal Mechanistic Investigation.

Nanoscale sulfur can be a multifunctional agricultural amendment to enhance crop nutrition and suppress disease. Pristine (nS) and stearic acid coated (cS) sulfur nanoparticles were added to soil planted with tomatoes (Solanum lycopersicum) at 200 mg/L soil and infested with Fusarium oxysporum. Bulk sulfur, ionic sulfate, and healthy controls were included. Orthogonal end points were measured in two greenhouse experiments, including agronomic and photosynthetic parameters, disease severity/suppression, mechanistic biochemical and molecular end points including the time-dependent expression of 13 genes related to two S bioassimilation and pathogenesis-response, and metabolomic profiles. Disease reduced the plant biomass by up to 87%, but nS and cS amendment significantly reduced disease as determined by area-under-the-disease-progress curve by 54 and 56%, respectively. An increase in planta S accumulation was evident, with size-specific translocation ratios suggesting different uptake mechanisms. In vivo two-photon microscopy and time-dependent gene expression revealed a nanoscale-specific elemental S bioassimilation pathway within the plant that is separate from traditional sulfate accumulation. These findings correlate well with time-dependent metabolomic profiling, which exhibited increased disease resistance and plant immunity related metabolites only with nanoscale treatment. The linked gene expression and metabolomics data demonstrate a time-sensitive physiological window where nanoscale stimulation of plant immunity will be effective. These findings provide mechanistic understandings of nonmetal nanomaterial-based suppression of plant disease and significantly advance sustainable nanoenabled agricultural strategies to increase food production.

Soil and foliar exposure of soybean (Glycine max) to Cu: Nanoparticle coating-dependent plant responses.

In this study, we investigated the effects of citric acid (CA) coated copper oxide nanoparticles (CuO NPs) and their application method (foliar or soil exposure) on the growth and physiology of soybean (Glycine max). After nanomaterials exposure via foliar or soil application, Cu concentration was elevated in the roots, leaves, stem, pod, and seeds; distribution varied by plant organ and surface coating. Foliar application of CuO NPs at 300 mg/L and CuO-CA NPs at 75 mg/L increased soybean yield by 169.5% and 170.1%, respectively. In contrast, foliar and soil exposure to ionic Cu with all treatments (75 and 300 mg/L) had no impact on yield. Additionally, CuO-CA NPs at 300 mg/L significantly decreased Cu concentration in seeds by 46.7%, compared to control, and by 44.7%, compared to equivalent concentration of CuO NPs. Based on the total Cu concentration, CuO NPs appeared to be more accessible for plant uptake, compared to CuO-CA NPs, inducing a decrease in protein content by 56.3% and inhibiting plant height by 27.9% at 300 mg/kg under soil exposure. The translocation of Cu from leaf to root and from the root to leaf through the xylem was imaged by two-photon microscopy. The findings indicate that citric acid coating reduced CuO NPs toxicity in soybean, demonstrating that surface modification may change the toxic properties of NPs. This research provides direct evidence for the positive effects of CuO-CA NPs on soybean, including accumulation and in planta transfer of the particles, and provides important information when assessing the risk and the benefits of NP use in food safety and security.

Role of Foliar Biointerface Properties and Nanomaterial Chemistry in Controlling Cu Transfer into Wild-Type and Mutant Arabidopsis thaliana Leaf Tissue.

Seven Arabidopsis thaliana mutants with differences in cuticle thickness and stomatal density were foliar exposed to 50 mg L-1 Cu3(PO4)2 nanosheets (NS), CuO NS, CuO nanoparticles, and CuSO4. Three separate fractions of Cu (surface-attached, cuticle, interior leaf) were isolated from the leaf at 0.25, 2, 4, and 8 h. Cu transfer from the surface through the cuticle and into the leaf varied with mutant and particle type. The Cu content on the surface decreased significantly over 8 h but increased in the cuticle. Cu derived from the ionic form had the greatest cuticle concentration, suggesting greater difficulty in moving across this barrier and into the leaf. Leaf Cu in the increased-stomatal mutants was 8.5-44.9% greater than the decreased stomatal mutants, and abscisic acid to close the stomata decreased Cu in the leaf. This demonstrates the importance of nanomaterial entry through the stomata and enables the optimization of materials for nanoenabled agriculture.

Impact of engineered nanomaterials on rice (Oryza sativa L.): A critical review of current knowledge.

After use, a large number of engineered materials (ENMs) are directly or indirectly released into the environment. This may threaten the agricultural ecosystem, especially with crops under high demand for irrigation water, such as rice (Oryza sativa L.), a crop that feeds nearly half of the world's population. However, consistent and detailed information on the effects of nanoparticles in rice is limited. This review is a systematic exploration of the effects of ENMs on rice, with a critical evaluation of the mechanisms reported in the literature by which different nanomaterials cause toxicity in rice. The physiological and biochemical effects engendered by the nanoparticles are highlighted, focusing on rice growth and development, ENMs uptake and translocation, gene expression changes, enzyme activity modifications, and secondary metabolite alterations.

Foliar Application of Copper Oxide Nanoparticles Suppresses Fusarium Wilt Development on Chrysanthemum.

Micronutrients applied as nanoparticles of metal oxides have shown efficacy in vegetable and other crops for improving yield and reducing Fusarium diseases, but their role in ornamental crop management has not been investigated. In 2017, 2018, and 2020, nanoparticles of CuO, Mn2O3, or ZnO were foliarly applied at 500 µg/mL (0.6 mg/plant) to chrysanthemum transplants and planted in potting soil noninfested or infested with Fusarium oxysporum f. sp. chrysanthemi. An untreated control and a commercial fungicide, Fludioxonil, was also included. Chrysanthemums treated with nanoscale CuO had a 55, 30, and 32% reduction in disease severity ratings compared to untreated plants in 2017, 2018, and 2020, respectively. Specifically, the average dry biomass for the three years was reduced 22% by disease, but treatment with nanoscale CuO led to a 23% increase when compared to controls. Similar trends with plant height were observed. Horticultural quality was improved 28% with nano CuO and was equal to the fungicide. Nanoscale Mn2O3 and the fungicide did not consistently reduce disease ratings or increase dry biomass each year. Nanoscale ZnO was ineffective. Nanoscale CuO-treated plants had 24 to 48% more Cu/g tissue than controls (P < 0.001). These findings agree with past reports on food crops where single applications of nanoscale CuO improved plant health, growth, and yield and could offer significant impacts for managing plant diseases on ornamentals.

Influence of Single and Combined Mixtures of Metal Oxide Nanoparticles on Eggplant Growth, Yield, and Verticillium Wilt Severity.

Verticillium wilt, caused by Verticillium dahliae, is one of the major diseases of eggplants. Nanoparticles (NPs) of CuO, Mn2O3, and ZnO were sprayed alone onto leaves of young eggplants and in different combinations and rates, and then seedlings were transplanted into soil infested with V. dahliae in the greenhouse and field between 2015 and 2018. All combinations of NPs were consistently less effective than CuO NPs applied alone at 500 µg/ml at increasing disease suppression, biomass, and fruit yield. CuO NPs were associated with an increase in fruit yield (17 and 33% increase) and disease suppression (28 and 22% reduction) in 2016 and 2017, respectively, when compared with untreated controls. However, this effect was negated in the greenhouse and field experiments when CuO NPs were combined with Mn2O3. Combining NPs of CuO with ZnO resulted in variable effects; amendments increased growth and suppressed disease in greenhouse experiments, but results were mixed in the field. Leaf tissue analyses from the greenhouse experiments showed that Cu concentration in leaves was reduced when CuO NPs were combined with other NPs, even when application rates were the same amount. A simple competition for entry sites may explain why combinations of CuO NPs and Mn2O3 NPs reduced efficacy but does not explain the lack of inhibition between Cu and Zn. NPs of CuO performed better than their larger bulk equivalent, and studies on application rate found 500 µg/ml was optimal. No phytotoxicity, as determined, by leaf burning, necrotic spots, or dead apical buds was noted even at the highest combined rates of 1,500 µg/ml.

Phylogenomic Analysis of a 55.1-kb 19-Gene Dataset Resolves a Monophyletic Fusarium that Includes the Fusarium solani Species Complex.

Scientific communication is facilitated by a data-driven, scientifically sound taxonomy that considers the end-user's needs and established successful practice. In 2013, the Fusarium community voiced near unanimous support for a concept of Fusarium that represented a clade comprising all agriculturally and clinically important Fusarium species, including the F. solani species complex (FSSC). Subsequently, this concept was challenged in 2015 by one research group who proposed dividing the genus Fusarium into seven genera, including the FSSC described as members of the genus Neocosmospora, with subsequent justification in 2018 based on claims that the 2013 concept of Fusarium is polyphyletic. Here, we test this claim and provide a phylogeny based on exonic nucleotide sequences of 19 orthologous protein-coding genes that strongly support the monophyly of Fusarium including the FSSC. We reassert the practical and scientific argument in support of a genus Fusarium that includes the FSSC and several other basal lineages, consistent with the longstanding use of this name among plant pathologists, medical mycologists, quarantine officials, regulatory agencies, students, and researchers with a stake in its taxonomy. In recognition of this monophyly, 40 species described as genus Neocosmospora were recombined in genus Fusarium, and nine others were renamed Fusarium. Here the global Fusarium community voices strong support for the inclusion of the FSSC in Fusarium, as it remains the best scientific, nomenclatural, and practical taxonomic option available.

Interactive effects of drought, organic fertilizer, and zinc oxide nanoscale and bulk particles on wheat performance and grain nutrient accumulation.

Drought (40% field moisture capacity), organic fertilizer (O-F; 10%), and nano vs. bulk-ZnO particles (1.7 vs. 3.5 mg Zn/kg) were assessed in soil to determine their interactive effects on wheat performance and nutrient acquisition. Drought significantly reduced (6%) chlorophyll levels, whereas nano and bulk-ZnO alleviated some stress, thereby increasing (14-16%) chlorophyll levels, compared to the control. O-F increased (29%) chlorophyll levels and counteracted Zn's effect. Drought delayed (3-days) panicle emergence; O-F, nano and bulk-ZnO each accelerated (5-days) panicle emergence under drought, relative to the control and absence of O-F. Drought reduced (51%) grain yield, while O-F increased (130%) yield under drought. Grain yield was unaffected by Zn treatment under drought but increased (88%) under non-drought condition with bulk-ZnO, relative to the control. Drought lowered (43%) shoot Zn uptake. Compared to the control, nano and bulk-ZnO increased (39 and 23%, respectively) shoot Zn in the absence of O-F, whereas O-F amendment enhanced (94%) shoot Zn. Drought increased (48%) grain Zn concentration; nano and bulk-ZnO increased (29 and 18%, respectively) grain Zn, relative to the control, and O-F increased (85%) grain Zn. Zn recovery efficiency was in the order O-F > nano-ZnO > bulk-ZnO, regardless of the water status. Grain Fe concentration was unaffected by drought, under which O-F significantly reduced grain Fe, and nano-ZnO significantly reduced grain Fe, in the absence of O-F. Nano and bulk-ZnO also significantly reduced grain Fe, with O-F amendment under drought. Drought can have dire consequences for food and nutrition security, with implications for human health. This study demonstrated that drought-induced effects in food crops can be partially or wholly alleviated by ZnO particles and Zn-rich O-F. Understanding the interactions of drought and potential mitigation strategies such as fertilization with Zn-rich organic manure and ZnO can increase options for sustaining food production and quality under adverse conditions.

Facile Coating of Urea With Low-Dose ZnO Nanoparticles Promotes Wheat Performance and Enhances Zn Uptake Under Drought Stress.

Zinc oxide nanoparticles (ZnO-NPs) hold promise as novel fertilizer nutrients for crops. However, their ultra-small size could hinder large-scale field application due to potential for drift, untimely dissolution or aggregation. In this study, urea was coated with ZnO-NPs (1%) or bulk ZnO (2%) and evaluated in wheat (Triticum aestivum L.) in a greenhouse, under drought (40% field moisture capacity; FMC) and non-drought (80% FMC) conditions, in comparison with urea not coated with ZnO (control), and urea with separate ZnO-NP (1%) or bulk ZnO (2%) amendment. Plants were exposed to ≤ 2.17 mg/kg ZnO-NPs and ≤ 4.34 mg/kg bulk-ZnO, indicating exposure to a higher rate of Zn from the bulk ZnO. ZnO-NPs and bulk-ZnO showed similar urea coating efficiencies of 74-75%. Drought significantly (p ≤ 0.05) increased time to panicle initiation, reduced grain yield, and inhibited uptake of Zn, nitrogen (N), and phosphorus (P). Under drought, ZnO-NPs significantly reduced average time to panicle initiation by 5 days, irrespective of coating, and relative to the control. In contrast, bulk ZnO did not affect time to panicle initiation. Compared to the control, grain yield increased significantly, 51 or 39%, with ZnO-NP-coated or uncoated urea. Yield increases from bulk-ZnO-coated or uncoated urea were insignificant, compared to both the control and the ZnO-NP treatments. Plant uptake of Zn increased by 24 or 8% with coated or uncoated ZnO-NPs; and by 78 or 10% with coated or uncoated bulk-ZnO. Under non-drought conditions, Zn treatment did not significantly reduce panicle initiation time, except with uncoated bulk-ZnO. Relative to the control, ZnO-NPs (irrespective of coating) significantly increased grain yield; and coated ZnO-NPs enhanced Zn uptake significantly. Zn fertilization did not significantly affect N and P uptake, regardless of particle size or coating. Collectively, these findings demonstrate that coating urea with ZnO-NPs enhances plant performance and Zn accumulation, thus potentiating field-scale deployment of nano-scale micronutrients. Notably, lower Zn inputs from ZnO-NPs enhanced crop productivity, comparable to higher inputs from bulk-ZnO. This highlights a key benefit of nanofertilizers: a reduction of nutrient inputs into agriculture without yield penalities.

Nutritional Status of Tomato (Solanum lycopersicum) Fruit Grown in Fusarium-Infested Soil: Impact of Cerium Oxide Nanoparticles.

In this study, the impact of cerium oxide nanoparticles on the nutritional value of tomato (Solanum lycopersicum) fruit grown in soil infested with Fusarium oxysporum f. sp. lycopersici was investigated in a greenhouse pot study. Three-week old seedlings of Bonny Best tomato plants were exposed by foliar and soil routes to nanoparticle CeO2 (NP CeO2) and cerium acetate (CeAc) at 0, 50, and 250 mg/L and transplanted into pots containing a soil mixture infested with the Fusarium wilt pathogen. Fruit biomass, water content, diameter, and nutritional content (lycopene, reducing and total sugar) along with elemental composition, including Ce, were evaluated. Fruit Ce concentration was below the detection limit in all treatments. Foliar exposure to NP CeO2 at 250 increased the fruit dry weight (67%) and lycopene content (9%) in infested plants, compared with the infested untreated control. Foliar exposure to CeAc at 50 mg/L reduced fruit fresh weight (46%) and water content (46%) and increased the fruit lycopene content by 11% via root exposure as compared with the untreated infested control. At 250 mg/L, CeAc increased fruit dry weight (94%), compared with the infested untreated control. Total sugar content decreased in fruits of infested plants exposed via roots to NP CeO2 at 50 mg/kg (63%) and 250 mg/kg (54%), CeAc at 50 mg/kg (46%), and foliarly at 50 mg/L (50%) and 250 mg/L (50%), all compared with the infested untreated control. Plants grown in Fusarium-infested soil had decreased fruit dry weight (42%) and lycopene content (17%) and increased total sugar (60%) and Ca content (140%), when compared with the noninfested untreated control (p ≤ 0.05). Overall, the data suggested minimal negative effects of NP CeO2 on the nutritional value of tomato fruit while simultaneously suppressing Fusarium wilt disease.

Metalloid and Metal Oxide Nanoparticles Suppress Sudden Death Syndrome of Soybean.

Soybeans (Glycine max) (V3 stage) were sprayed once with nanoparticles (NPs) of AgO, B, CeO, CuO, MnO, MoO3, SiO, TiO, or ZnO and exposed to Fusarium virguliforme, the cause of sudden death syndrome. Up to 80% root rot was observed in greenhouse experiments. However, NP CuO, B, MoO3, or ZnO reduced the root rot severity by 17-25%. Infected roots and shoots had significant changes in B, Mg, P, S, Si, and Zn, but NP treatment restored levels to that of the healthy control. For example, the increased root Mg and Mn contents induced by disease were reversed by NP B and Mn amendments. In vitro assays found that the NPs did not inhibit the pathogen. This, along with the restoration of altered nutrient levels in the plant tissue, suggests that modulated plant nutrition increased disease defense. Treatment of seedlings with nanoscale micronutrients may be a new tool in promoting soybean health.

Zinc oxide nanoparticles alleviate drought-induced alterations in sorghum performance, nutrient acquisition, and grain fortification.

Drought is a major environmental event affecting crop productivity and nutritional quality, and potentially, human nutrition. This study evaluated drought effects on performance and nutrient acquisition and distribution in sorghum; and whether ZnO nanoparticles (ZnO-NPs) might alleviate such effects. Soil was amended with ZnO-NPs at 1, 3, and 5 mg Zn/kg, and drought was imposed 4 weeks after seed germination by maintaining the soil at 40% of field moisture capacity. Flag leaf and grain head emergence were delayed 6-17 days by drought, but the delays were reduced to 4-5 days by ZnO-NPs. Drought significantly (p < 0.05) reduced (76%) grain yield; however, ZnO-NP amendment under drought improved grain (22-183%) yield. Drought inhibited grain nitrogen (N) translocation (57%) and total (root, shoot and grain) N acquisition (22%). However, ZnO-NPs (5 mg/kg) improved (84%) grain N translocation relative to the drought control and restored total N levels to the non-drought condition. Shoot uptake of phosphorus (P) was promoted (39%) by drought, while grain P translocation was inhibited (63%); however, ZnO-NPs lowered total P acquisition under drought by 11-23%. Drought impeded shoot uptake (45%), grain translocation (71%) and total acquisition (41%) of potassium (K). ZnO-NP amendment (5 mg/kg) to drought-affected plants improved total K acquisition (16-30%) and grain K (123%), relative to the drought control. Drought lowered (32%) average grain Zn concentration; however, ZnO-NP amendments improved (94%) grain Zn under drought. This study represents the first evidence of mitigation of drought stress in full-term plants solely by exposure to ZnO-NPs in soil. The ability of ZnO-NPs to accelerate plant development, promote yield, fortify edible grains with critically essential nutrients such as Zn, and improve N acquisition under drought stress has strong implications for increasing cropping systems resilience, sustaining human/animal food/feed and nutrition security, and reducing nutrient losses and environmental pollution associated with N-fertilizers.

Addition-omission of zinc, copper, and boron nano and bulk oxide particles demonstrate element and size -specific response of soybean to micronutrients exposure.

Plant response to microelements exposure can be modulated based on particle size. However, studies are lacking on the roles of particle size and specific microelements in mixed exposure systems designed for plant nutrition, rather than toxicology. Here, an addition-omission strategy was used to address particle-size and element-specific effects in soybean exposed to a mixture of nano and bulk scale oxide particles of Zn (2 mg Zn/kg), Cu (1 mg Cu/kg) and B (1 mg B/kg) in soil. Compared to the control, mixtures of oxide particles of both sizes significantly (p < 0.05) promoted grain yield and overall (shoot and grain) Zn accumulation, but suppressed overall P accumulation. However, the mixed nano-oxides, but not the mixed bulk-oxides, specifically stimulated shoot growth (47%), flower formation (63%), shoot biomass (34%), and shoot N (53%) and K (42%) accumulation. Compared by particle size, omission of individual elements from the mixtures evoked significant responses that were nano or bulk-specific, including shoot growth promotion (29%) by bulk-B; inhibition (51%) of flower formation by nano-Cu; stimulation (57%) of flower formation by bulk-B; grain yield suppression (40%) by nano-Zn; B uptake enhancement (34%) by bulk-Cu; P uptake stimulation by nano-Zn (14%) or bulk-B (21%); residual soil N (80%) and Zn (42%) enhancement by nano-Cu; and residual soil Cu enhancement by nano-Zn (72%) and nano-B (62%). Zn was responsible for driving the agronomic (biomass and grain yield) responses in this soil, with concurrent ramifications for environmental management (N and P) and human health (Zn nutrition). Overall, compared to bulk microelements, nanoscale microelements played a greater role in evoking plant responses.