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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.

The use of inorganic amendments to immobilize cadmium is an eco-friendly approach. The present study aimed to evaluate sulfur nanoparticles (SNPs) for the mitigation of Cd stress in saffron (Crocus sativusL.). A factorial layout based on a completely randomized design with four replications was conducted in greenhouse conditions. Treatments consisted of Cd concentration (0, 15, 30, and 45 mg kg−1) and sulfur amendments (control, SNPs, and bulk sulfur particles (BSPs) at 100 and 200 mg kg−1). In non-contaminated plants, application of BSPs 200 increased stigma and flower dry weight by 127 and 108%, respectively. At Cd 30 mg kg−1, using BSPs 100 yielded the highest stigma and flower dry weight. More daughter corms were produced by using BSPs 100 in control plants and BSPs 200 or SNPs 100 in 45 mg kg−1Cd. The highest root dry weight measured in Cd 15 mg kg−1+ SNPs 100 and Cd 45 mg kg−1+ SNPs 200. The fertilization effect of BSPs 200 was reflected in the dry weight of the leaf, daughter corms, root, and daughter corm diameter. Roots accumulated the highest Cd concentration, followed by leaves, corms, and stigma. The bioconcentration factor (BCF) in plant tissues was in descending order (BCFroot > BCFleaves > BCFcorm > BCFstigma). The highest total Cd accumulation was detected in 45 mg kg−1Cd along with SNPs 200. Overall, saffron seemed to be capable of phytostabilizing in managing Cd toxicity by lowering its translocation to aboveground tissues, especially to the stigma.

The use of inorganic amendments to immobilize cadmium is an eco-friendly approach. The present study aimed to evaluate sulfur nanoparticles (SNPs) for the mitigation of Cd stress in saffron (Crocus sativusL.). A factorial layout based on a completely randomized design with four replications was conducted in greenhouse conditions. Treatments consisted of Cd concentration (0, 15, 30, and 45 mg kg−1) and sulfur amendments (control, SNPs, and bulk sulfur particles (BSPs) at 100 and 200 mg kg−1). In non-contaminated plants, application of BSPs 200 increased stigma and flower dry weight by 127 and 108%, respectively. At Cd 30 mg kg−1, using BSPs 100 yielded the highest stigma and flower dry weight. More daughter corms were produced by using BSPs 100 in control plants and BSPs 200 or SNPs 100 in 45 mg kg−1Cd. The highest root dry weight measured in Cd 15 mg kg−1+ SNPs 100 and Cd 45 mg kg−1+ SNPs 200. The fertilization effect of BSPs 200 was reflected in the dry weight of the leaf, daughter corms, root, and daughter corm diameter. Roots accumulated the highest Cd concentration, followed by leaves, corms, and stigma. The bioconcentration factor (BCF) in plant tissues was in descending order (BCFroot > BCFleaves > BCFcorm > BCFstigma). The highest total Cd accumulation was detected in 45 mg kg−1Cd along with SNPs 200. Overall, saffron seemed to be capable of phytostabilizing in managing Cd toxicity by lowering its translocation to aboveground tissues, especially to the stigma.

Among all the nutrients, nitrogen (N) and phosphorous (P) are the most limiting factors reducing wheat production and productivity world-wide. These macronutrients are directly applied to soil in the form of fertilizers. However, only 30–40% of these applied fertilizers are utilized by crop plants, while the rest is lost through volatilization, leaching, and surface run off. Therefore, to overcome the deficiency of N and P, it becomes necessary to improve their use efficiency. Marker-assisted selection (MAS) combined with traditional plant breeding approaches is considered best to improve the N and P use efficiency (N/PUE) of wheat varieties. In this study, we developed and evaluated a total of 98 simple sequence repeat (SSR) markers including 66 microRNAs and 32 gene-specific SSRs on a panel of 10 (N and P efficient/deficient) wheat genotypes. Out of these, 35 SSRs were found polymorphic and have been used for the study of genetic diversity and population differentiation. A set of two SSRs, namely miR171a and miR167a were found candidate markers able to discriminate contrasting genotypes for N/PUE, respectively. Therefore, these two markers could be used as functional markers for characterization of wheat germplasm for N and P use efficiency. Target genes of these miRNAs were found to be highly associated with biological processes (24 GO terms) as compared to molecular function and cellular component and shows differential expression under various P starving conditions and abiotic stresses.

Rice is known to accumulate arsenic (As) in its grains, posing serious health concerns for billions of people globally. We studied the effect of nanoscale sulfur (NS) on rice seedlings and mature plants under As stress. NS application caused a 40% increase in seedling biomass and a 26% increase in seed yield of mature plants compared to untreated control plants. AsIII exposure caused severe toxicity to rice; however, coexposure of plants to AsIII and NS alleviated As toxicity, and growth was significantly improved. Rice seedlings treated with AsIII + NS produced 159 and 248% more shoot and root biomass, respectively, compared to plants exposed to AsIII alone. Further, AsIII + NS-treated seedlings accumulated 32 and 11% less As in root and shoot tissues, respectively, than the AsIII-alone treatment. Mature plants treated with AsIII + NS produced 76, 110, and 108% more dry shoot biomass, seed number, and seed yield, respectively, and accumulated 69, 38, 18, and 54% less total As in the root, shoot, flag leaves, and grains, respectively, compared to AsIII-alone-treated plants. A similar trend was observed in seedlings treated with AsV and NS. The ability of sulfur (S) to alleviate As toxicity and accumulation is clearly size dependent as NS could effectively reduce bioavailability and accumulation of As in rice via modulating the gene expression activity of As transport, S assimilatory, and glutathione synthesis pathways to facilitate AsIII detoxification. These results have significant environmental implications as NS application in agriculture has the potential to decrease As in the food chain and simultaneously enable crops to grow and produce higher yields on marginal and contaminated lands.

Widespread use of silver nanoparticles (Ag NPs) as pesticides and fungicides in agriculture is a major environmental concern. In the present study, soybean (Glycine maxL.) was grown in Ag NP (0–62.5 mg kg−1)-amended soil with or without the addition of glutathione (GSH). Ag NPs exerted severe phytotoxicity and caused the reduction of shoot and root biomass and total number of nodules or completely inhibited nodule formation at doses above 31.25 mg kg−1. Synchrotron-based techniques were applied to analyze Ag speciation in both the soil and the soybean root tissues at harvest. The results indicate that the majority of Ag remained in the form of Ag NPs and that 23% was present as Ag2S in soil; in both root and nodule tissues, Ag–GSH was the main component (40.6–88%) other than Ag NPs (12–59.4%), highlighting the important role of GSH in alleviating the Ag NP-induced toxicity. The addition of 0.8 mM GSH not only significantly increased fresh biomass by 85% in the 62.5 mg kg−1Ag NP treatment but also decreased Ag accumulation by 24.8–27% in soybean tissues. Although the addition of 0.8 mM GSH reduced the nodule number and weight as compared to the control, the total nitrogen content in soybean co-treated with Ag NP and GSH was more than 5-fold higher than that in the Ag NP alone treatments, suggesting that GSH may be utilized as a nitrogen source while simultaneously alleviating Ag NP toxicity. The shoot and root contents of thiol compounds (cysteine and gamma-glutamylcysteine) in the GSH treatments were several folds higher than that in the control and Ag NP alone treatments. Further, higher levels of essential amino acids, particularly alanine, glutamate, and glutamine which play important role in N assimilation in plants, in soybean across all the treatments further confirmed that GSH was utilized as a nitrogen source, resulting in enhanced soybean growth. Taken together, this study clearly demonstrated the negative impact of Ag NPs on soybean productivity and N fixation and highlights the protective role of GSH against Ag NP-induced toxicity. These findings have significant relevance for developing future strategies to minimize crop loss in marginal or contaminated soils, subsequently enhancing global food security.

Background: Major intrinsic proteins (MIPs) are membrane channel proteins which maintain water homeostasis and permeable to small molecules across the membrane. Objective: Genome analysis of Brachypodium MIPs (BdMIPs) gene family and in silico studies are based on available bioinformatic tools. Further comparison and evolutionary study of MIPs members were performed within grass family. Method: MIPs sequences were retrieved from Gramene database, aligned and weblogo was generated. Physio-chemical analysis was performed and phylogenetic tree was constructed by neighbor-joining. In silico expression profile of BdMIP genes was searched and image maps were generated by CIMMiner web-based server. Result: Genome wide analysis of B. distachyon identified 33MIP genes and classified into four major groups. Analysis of motifs and transmembrane domains strongly supported their identity as a member of the MIP super family. Duplication analysis revealed that 4 genes were tandemly duplicated and no segmental duplication events in BdMIPs were observed. Prediction of cis-elements in BdMIP promoter region gave more insight into regulation mechanism under hormonal and stress conditions. In silico expression profile under development stages provided insight into expression pattern of BdMIP genes. Conclusion: Total 33 MIPs were predicted in Brachypodium genome. Tandem duplication event was dominant phenomenon over segmental duplication in BdMIPs. Orthology analysis revealed Brachypodium MIP members were close to grass family MIP members compared to Arabidopsis. Compilation of this work will significantly contribute to the understanding of an evolutionary and biological importance of MIP genes in grass family and thus provide a set up for functional genomics studies in Brachypodium.

Although both antibiotic residues and metal-based nanoparticles (NPs) are common emerging pollutants, little is known about their potential co-contaminant interactions, including resulting impacts on sensitive biota such as food crops. This study assessed the impact of tetracycline (TC, 5–20 mg L−1) and titanium dioxide (TiO2, 500–2000 mg L−1) NPs co-exposure on rice (Oryza sativaL.) under a 10 d hydroponic exposure. Plant biomass, contaminant content (TC, Ti), oxidative stress enzymes, and macro-/micronutrient contents were measured in rice shoots and roots as a function of exposure. Under TC alone exposure, dose-dependent toxicity (biomass, oxidative stress enzymes) and TC accumulation were observed and the levels of several key elemental nutrients were decreased. For example, root biomass treated with 5 and 20 mg L−1TC was reduced by 18.8% and 62.5%, respectively, relative to the control. The contents of K, P, and S in 10 and 20 mg L−1TC treated rice shoots were approximately 80% of the unamended control. Under co-exposure, the presence of TiO2NPs significantly enhanced the TC treated rice growth in terms of plant size and total biomass. In addition, TiO2NPs significantly reduced the levels of TC in rice shoots and roots, as well as oxidative stress enzymes, back to the level of unamended controls and also enabled recovery of TC-induced nutrient deficiency. It is worth mentioning that both contaminants resulted in severe iron deficiency (44–76% decreases of Fe in all the treatments were evident) under both single and co-exposure treatments. Abiotic sorption data indicates that TC phytotoxicity was prevented due to sorption of the antibiotic onto NP TiO2(a maximum amount was 2.62 mg g−1), resulting in significantly decreased availability to the rice seedlings. The presence of TC increased the Ti content in rice roots, which could be ascribed to the alteration of surface charges of TiO2NPs as affected by TC. Antagonistic and synergistic effects of TiO2NPs and TC on rice were analyzed using three methods, including toxicity unit (TU), additional index (AI), and mixture toxicity index (MTI), all of which indicated under co-exposing condition, TiO2NPs and TC interacted antagonistically, resulting in an overall alleviation of phytotoxicity and enhanced plant health.

Although engineered nanomaterial (ENM) uptake, transport and response mechanisms in plants have received increased attention in recent years, many questions regarding ENM risks to the environment and to food safety remain unanswered. The impact of ENM interactions with co-existing organic/inorganic contaminants, including secondary ENMs, remains poorly understood. The physiological and molecular response of zucchini (Cucurbita pepoL.) under conditions of nanomaterial combined treatments (NMCT) with binary combinations of nanoparticles (NPs) of cerium oxide (CeO2), lanthanum oxide (La2O3), copper oxide (CuO), and zinc oxide (ZnO) (500 mg L−1) and cadmium sulfide quantum dots (CdS QDs) (100 mg L−1) were tested (for 21 days, in vermiculite) and compared with the respective individual (NMIT) and bulk material (BMT) treatments. The ICP-MS results within specific tissues upon exposure to NMCT or NMIT demonstrated that the metal content varied significantly upon co-exposure, including instances of antagonistic effects; La uptake was significantly decreased (50–80%, compared to NMIT or NMCT) upon CeO2NP co-exposure whereas La2O3NPs caused a complete deregulation (2–5-fold higher) of Cu uptake upon CuO NP co-exposure. Expression analysis of genes previously shown as responsive to ENM exposure confirmed the involvement of the chloroplast in plant response; ORF31, an electron carrier down-regulated in all treatments, showed potential as a biomarker of exposure/effects. Principal component analysis on plant physiological and molecular response provided insight into the nature of phytotoxicity under NMIT and NMCT. This systematic approach is useful for characterizing the risk associated with ENMs, providing mechanistic interpretations and holistic perspectives for complex systems of contamination.

Metal-based nanoparticles (NPs) can cause toxicity to terrestrial plants, however there is little understanding of plant defense mechanisms that may counteract nanotoxicity. In the present study, we investigated the defense mechanisms of Arabidopsis thalianain response to 250 mg L−1and 1000 mg L−1cerium oxide (CeO2) and indium oxide (In2O3) NPs exposure. Excessive amounts of total reactive oxygen species (ROS) were measured upon exposure to both NPs, demonstrating clear oxidative stress in Arabidopsis. Analysis of ROS scavenger activity indicated that activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and peroxidase (POD) were significantly elevated upon exposure to CeO2NPs, while these elevations were only evident for SOD and POD activities in the In2O3NP treatments. In addition, the activities of glutathione S-transferase (GST) and glutathione reductase (GR) were increased by approximately 15% and 51% by 1000 mg L−1CeO2and In2O3treatment, respectively. Furthermore, the activities of phenylanine ammonialyase (PAL) and polyphenol oxidase (PPO) were greatly induced in response to both types of NPs. Additionally, both NPs disrupted the uptake of elemental nutrients, as is evident from the significantly lower levels of Fe accumulation in Arabidopsisroot tissues exposed to CeO2and In2O3NPs. These results were further supported by the differential regulation of three iron-regulating genes, including ferric chelate reductase (FRO), iron-regulated transporter (IRT) and ferritin (FER), at various time points. The findings provide useful mechanistic information for plant detoxification pathways following NP exposure.

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 oxysporumf. 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.

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 plantaS 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.

Seven Arabidopsis thalianamutants with differences in cuticle thickness and stomatal density were foliar exposed to 50 mg L–1Cu3(PO4)2nanosheets (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.

In agriculture, loss of crop yield to pathogen damage seriously threatens efforts to achieve global food security. In the present work, “organic” elemental sulfur nanoparticles (SNPs) were investigated for management of the fungal pathogen Fusarium oxysporumf. sp. lycopersicion tomatoes. Foliar application and seed treatment with SNPs (30–100 mg/L, 30 and 100 nm) suppressed pathogen infection in tomatoes, in a concentration- and size-dependent fashion in a greenhouse experiment. Foliar application with 1 mg/plant of 30 nm SNPs (30-SNPs) exhibited the best performance for disease suppression, significantly decreasing disease incidence by 47.6% and increasing tomato shoot biomass by 55.6% after 10 weeks application. Importantly, the disease control efficacy with 30-SNPs was 1.43-fold greater than the commercially available fungicide hymexazol. Mechanistically, 30-SNPs activated the salicylic acid-dependent systemic acquired resistance pathway in tomato shoots and roots, with subsequent upregulation of the expression of pathogenesis-related and antioxidase-related genes (upregulated by 11–352%) and enhancement of the activity and content of disease-related biomolecules (enhanced by 5–49%). In addition, transmission electron microscopy imaging shows that SNPs were distributed in the tomato stem and directly inactivated in vivopathogens. The oxidative stress in tomato shoots and roots, the root plasma membrane damage, and the growth of the pathogen in stem were all significantly decreased by SNPs. The findings highlight the significant potential of SNPs as an eco-friendly and sustainable crop protection strategy.

Seed priming is a cost-effective, practical, environmental, and farmer-friendly method to improve seed germination that can potentially increase the growth and yield of plants. The priming process enhances various physiological and biochemical mechanisms of defense and empowers the seeds or seedlings to overcome different environmental stresses. However, under critical circumstances, plants are hindered from absorbing specific chemical priming reagents owing to their larger size, molecular structure, or lack of carriers. Therefore, nanoscale materials having exceptional physiochemical properties and a large surface/volume ratio are expected to be better absorbed by the seeds/seedlings as priming agents in comparison to bulk chemicals and can trigger enhanced molecular interactions at the cellular level. Further, the flexibility in altering the surface chemical properties of the nanomaterials can facilitate better interaction with the seeds/seedlings while inhibiting the wastage of priming agents. In this review, we have systematically discussed the potentiality of various nanostructured materials as priming agents in alleviating the adverse effects of various abiotic stresses, viz., drought, salinity, high temperature, cold temperature, and heavy metals, by studying the growth parameters and physiological and biochemical response of various crop plants subjected to these stress conditions. Also, we have highlighted the molecular mechanism and activation of genes involved in enabling abiotic stress tolerance in plants after being primed with nanostructured materials.