Recipient Organization
THE UNIVERSITY OF TEXAS AT EL PASO
500 WEST UNIVERSITY AVE
EL PASO,TX 79902
Performing Department
(N/A)
Non Technical Summary
Over the next thirty years, the global agricultural system will face unprecedented challenges to provide nutritious and environmentally sustainable food for the growing population. By 2050, the world's agricultural production will need to increase by 60% to meet the projected population of 9.7 billion. However, the yearly increases in production brought by the green revolution appear to be ending. In a 2019 review, we showed that in the last forty years, the yield growth trend has been declining for nearly all crops. Furthermore, droughts, heatwaves, and floods brought on by climate change are placing added pressure on food production. There are seven essential plant micronutrient elements [Iron (Fe), Manganese (Mn), Zinc (Zn), Molybdenum (Mo), Copper (Cu), Boron (B), and Chlorine (Cl)]. Although the requirements of micronutrients in plants are minimal (0.1-200 mg/Kg), they are essential for their life cycle completion, and they have become limiting factors for crop productivity in many agricultural soils. Intensive cropping use of macronutrient fertilizers with low impurities of other elements, and modern irrigation systems have led to higher crop production but also to depletion of phytoavailable micronutrients. Current agricultural practices try to deliver nutrients to soil and crops; unfortunately, they are highly inefficient, with losses averaging 10-75%. Therefore, increasing agricultural production using current methods is not possible. One important strategy is to investigate and develop novel new technologies that effectively deliver micronutrients to crops so as to address the challenges of providing nutritious and environmentally sustainable food for the growing population.This project will involve translational research from the fields of phytology, chemistry, toxicology, engineering and material sciences toward the goal of sustainable nano-enabled agriculture. The goal of this project is to explore, understand and optimize the use of nanoscale Mn and Fe species as novel fertilizers. The underlying hypothesis is that nanoscale Mn and Fe species can improve photosynthesis, reduce abiotic stress, and improve yield substantially beyond their conventional counterparts. Our experimental plan consists of three interconnected objectives. First, we will investigate the transport and effects of foliar and seed-applied Mn and Fe nanomaterials on four representative plant species. The second phase of our experimental plan will evaluate the effects of said ENMs on plants exposed to abiotic stress. Last, the most promising ENM will be evaluated in field experiments.
Animal Health Component
30%
Research Effort Categories
Basic
40%
Applied
30%
Developmental
30%
Goals / Objectives
Nanoscale manganese and iron micronutrients to increase photosynthesis, crop yield, and abiotic stress tolerance. PI-Jose Hernandez-Viezcas, Co-PI-Jorge Gardea-Torresdey, University of Texas at El Paso (UTEP)Co-PI-Jason C. White, Co-PI-Nubia Zuverza-Mena, Connecticut Agricultural Experiment Station (CAES)Co-Pi-Vinka Craver, University of Rhode Island (URI)This is a Grant submitted to the USDA AFRI Priority Code A1511, "Nanotechnology for Agricultural and Food Systems" Over the next thirty years, the global agricultural system will face unprecedented challenges to provide nutritious and environmentally sustainable food for the growing population. By 2050, the world's agricultural production will need to increase by 60% to meet the projected population of 9.7 billion. Furthermore, droughts, heatwaves, and floods brought on by climate change are placing added pressure on food production. There is growing certainty that nanotechnology can be a critical tool to increase agricultural productivity to achieve and maintain global food security. Our previous work shows that nanoscale micronutrients Mn and Fe have multifunctionality, uniquely increasing photosynthesis as a function of small particle size while simultaneously up-regulating the production of antioxidant enzymes and reducing the effects of abiotic stress. However, there are gaps in knowledge about the mechanisms that are activated by nanoscale Mn and Fe species. Furthermore, there is a lack of understanding of the fate and transport of engineered nanomaterials (ENM) upon foliar and seed application. Toward the goal of creating an optimal nano-enabled fertilizer, we aim to evaluate the effects of four synthesized (three chemically and one biosynthesized) nanoscale Mn and Fe species on four model crops under two abiotic stressors, drought, and salinity. Our experimental plan consists of three interconnected objectives.Objective 1. Evaluate and understand the factors and mechanisms affecting four model plants under foliar and seed exposure to nanoscale Mn and Fe species. -A preliminary study will identify the optimal dosage (Foliar and seed) of micronutrient ENMs for all plant species.-A large experimental setup will expose (foliar and seed) the model plants, which will be sampled and analyzed during the full life cycle.-Analysis will include physiological measurements, crop gas exchange, metabolomics, enzyme activity, trace analysis and imaging (hyperspectral, two-photon, Micro XRF/XANES, submicron IR/Raman mapping and TEM)Objective 2. Elucidate the efficacy of nanoscale Mn and Fe species to reduce plant abiotic stress effects. An experimental setup will evaluate the nanoscale micronutrient effects on the plant's response to abiotic stress.Objective 3. Validate a nanoscale micronutrient ENM performance on the crop's response to abiotic stress in a field experiment. Building on the preliminary studies, one or more nanoscale micronutrients will be evaluated against crop abiotic stress in a field study. Crop growth, yield and nutritional quality of the edible tissue in a real environment will be evaluated.We anticipate that the outcomes will enable us to have a thorough mechanistic understanding of critical Mn and Fe micronutrient ENM-plant interactions, which in turn will enable us to maximize the effect ofnanoscale materials on crops.
Project Methods
MethodsObjective 1. Evaluate and understand the factors and mechanisms affecting four model plants under foliar and seed exposure to nanoscale Mn and Fe species.Our team will biosynthesize manganese oxide nanoparticles [(BIO)MnONPs] using Pseudomonas putida GB-1, a natural isolate. Briefly, the Pseudomonas will be cultured in sterile batch reactors with 50 mL Leptothorix media at 30°C and 144 RPM. The source of manganese in the media is 0.1 mM MnCl2. For all ENM, size, crystal structure, oxidation state, hydrodynamic size and ζ potential will be verified using transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and dynamic light scattering (DLS). Ion controls with Mn and Fe concentrations equivalent to the nanomaterials will be obtained from manganese sulfate (MnSO4 H2O) and iron sulfate (FeSO4 7H2O).Screening studies: Two soils will be used for the proposed experiments, a sandy loam from the CAES Lockwood farm in Hamden CT and a sandy loam from Texas AgriLife Research Center in El Paso, TX. Soils will be mixed (50/50) with potting media as done in previous work by the investigators but will again be thoroughly characterized for organic matter content, pH, sand/silt/clay content, clay mineralogy and cation exchange capacity and elemental analysis.Seeds (wheat, corn, soybean and lettuce) will be surface sterilized with 1% sodium hypochlorite (NaOCl) solution for 5 minutes and then rinsed with DI water. For seed exposure, seeds will be dosed with ENM using a novel vacuum infiltration technique developed at CAES that takes advantage of the air pockets in seed coats.One hundred seeds of each plant (soybean, wheat, corn and lettuce) will be placed in 30 mL suspensions of ENMs [(Bio)MnOx, Mn3O4, Fe3O4, and MnFe2O4] and controls at concentrations of 0, 0.5, 1.0, 10, 50, 100 and 500 mg/L. Seeds will be germinated in vermiculite, after 15 days uniform plantlets will be selected sown individually in five-liter garden pots. Pots will be kept well-watered and ten replicates per ENM concentration will be used for the preliminary experiment. For foliar preliminary studies, Seeds (wheat, corn, soybean and lettuce) will be surface sterilized with 1% NaOCl solution for 5 minutes and then rinsed with DI water. Seeds will be germinated in vermiculite, after 15 days uniform plantlets will be selected and sown individually in five-liter garden pots. Pots will be kept well-watered and ten replicates per ENM concentration will be used for the foliar application preliminary experiment. Approximately one week before flowering, plants (Soybean, Corn, Wheat and lettuce) will be sprayed with DI water or 10, 50, 100 mg/L of the ENM (BioMnOx, Mn3O4, Fe3O4 or MnFe2O4) and ionic solutions (MnSO4 H2O, FeSO4 7H2O). Plants will be sprayed daily for 1, 4 or 7 days; each plant will receive 2 ml of solution per application.Changes in the photosynthetic rate, leaf gas exchange and stomatal conductance will be monitored every 10 days after sowing, until the plants are harvested. Also, plants will be analyzed for these parameters before and after foliar application of nanomaterials. At the end of their reproductive growth cycle, plants will be removed from the soil and cleaned.We will expose the seeds of the four plant species to the selected concentrations of ENMs and corresponding ionic controls. A total of 15 replicates per treatment will be used in this experiment.For the foliar exposure, ENM and ionic species will be applied approximately one week before flowering, at a concentration (e.g. 10, 50 or 100 mg/L) and frequencies (e.g. 1, 4 or 7 days) determined as optimum in the preliminary study. Plants will complete their lifecycle, and studies will be performed during this period. Plants will be evaluated for changes in the gas exchange, growth, yield and Reactive Oxygen Species (catalase, ascorbate peroxidase and superoxide dismutase). In addition, tissues will be analyzed by a transcriptomic gene expression approach currently in use by the Project Team. Element translocation and Time-Dependent Metabolomic Analysis will be evaluated. To have a better understanding of the fate and transport of the nanomaterials, TEM Analysis, Synchrotron techniques (microXRF and XANES) and O-PTIR-Raman analysis will be performed.Dark field hyperspectral microscopy and two-photon microscopic analysis will be performed after every foliar application to understand the fate and accumulation of the ENMs across the leaf surface. Performance comparison between chemically and biologically synthetize MnOx ENM: Plant growth and environmental considerations: Once the plant studies finalized and the performance of both nanoparticles in terms of mass of plant or fruit production is established, the environmental impacts of the use of both nanoparticles will be determined using a Life Cycle Assessment approach. The Life Cycle Assessment (LCA) approach will be used to evaluate the environmental impact of the use of nanoparticles for agricultural purposes in different geographical regions.Objective 2. Elucidate the efficacy of nanoscale Mn and Fe species to reduce plant abiotic stress effects.For the seed exposure experiment, seeds will be exposed to ENMs as previously described in objective 1. Plants will be grown to their last vegetative stage before inducing abiotic stress. For drought stress, we will start a 20 day drought characterized by a 20% soil moisture measured by soil moisture probe. Plants soil humidity will be increased to 50% after 20 days. For salt stress, 100mL of 100mM NaCl, will be introduced to the soil followed by another dose 10 days later. Controls will be designed as absolute control and negative control, which represent plants exposed to no nanomaterials or abiotic stress, and exposed to no nanomaterials but only abiotic stress, respectively. Foliar application will start the same day as the abiotic stress input.Gas exchange parameters (photosynthetic rate, leaf gas exchange and stomatal conductance) described in objective 1 will be evaluated before the abiotic stress (drought and salinity) and every day after. Chlorophyll will also be measured before and every day after the abiotic stress using a SPAD meter. ROS scavenging enzyme activity (catalase, ascorbate peroxidase and superoxide dismutase) and Malondialdehyde formation will be analyzed one time before drought stress (day -1), during the drought on days 5 and 15 (out of 20 days of drought stress) and after the drought day 25. For salt stress, enzyme activity and malondialdehyde will be evaluated before stress, and the days after the salt addition. At the end of their reproductive growth cycle, yield and physiological parameters (biomass, size of shoot and root, leaf area). Plants will be sectioned and dried at 70? C before analysis using ICP-OES or MS.A time-dependent metabolomic profiling analysis, will allow us to identify if there is increased stress resistance related metabolites induced by the nanoscale treatment.Objective 3. Validate a nanoscale micronutrient ENM performance on the crop's response to abiotic stress. Plants will receive standard fertilization regiments and incidental pests will be controlled as needed by conventional practices. Experimental setup will be similar than Objective 2. Briefly, there will be Control (No ENM, no Stress), Negative Control (only abiotic stress), treatments (abiotic stress + ENMs). Field experiments will allow us to calculate crop growth, yield and nutritional quality of the edible tissue in a real environment. The Taguchi orthogonal design will allow robust statistical analysis of how nanoparticle and soil parameters affect plant quality. When the requirements of normality and homogeneity of variances are met, one-way Analysis of Variance (ANOVAs) will be performed to establish significant differences between treatments (the variation due to each factor).