Carbon nanomaterials are a superior soil amendment for sandy soils than biochar based on impacts on lettuce growth, physiology and soil biochemical quality.

A significant bottleneck of current agricultural systems remains the very low agronomic efficiency of conventional agrochemicals, particularly in sandy soils. Carbon nanomaterials (CNMs) have been proposed to address this inefficiency in sandy soils, which could potentially improve soil fertility and enhance crop growth and physiological processes. However, the effects of different rates of CNMs on crop physiological and soil biochemical quality in sandy soils must be compared to other carbon sources (e.g., biochar) before CNMs can be broadly used. To address this, a 70-day pot experiment was set up, growing lettuce under ten treatments: a negative control with no CNMs, biochar or fertilizer; a fertilizer-only control; three CNMs-only unfertilized treatments (CNMs at 200, 400 and 800 mg kg-1 soil); two biochar treatments with fertilizer (biochar at 0.5% and 1% by soil mass + fertilizer); and three CNMs treatments with fertilizer (CNMs at 200, 400 and 800 mg kg-1 soil + fertilizer). A novel amorphous, water-dispersible, and carboxyl-functionalized CNMs with pH of 5.5, zeta potential of -40.6 mV and primary particle diameter of 30-60 nm was used for this experiment. Compared to the fertilizer-only control, CNMs applied at low to medium levels (200-400 mg kg-1) significantly increased lettuce shoot biomass (20-21%), total chlorophyll (23-27%), and fluorescence and photosynthetic activities (4-10%), which was associated with greater soil nutrient availability (N: 24-58%, K: 68-111%) and higher leaf tissue accumulation (N: 25-27%; K: 66%). Low to medium levels of CNMs also significantly increased soil biochemical properties, such as higher soil microbial biomass carbon (27-29%) and urease enzyme activity (34-44%) relative to fertilizer-only applications. In contrast, biochar (0.5%) increased lettuce biomass relative to fertilizer-only but had no significant effect on soil fertility and biological properties. These results suggest that CNMs at low to medium application rates are a superior carbon-based amendment relative to biochar in sandy soils.

Integrating nanotechnology with plant microbiome for next-generation crop health.

Nanotechnology has enormous potential for sustainable agriculture, such as improving nutrient use efficiency, plant health, and food production. Nanoscale modulation of the plant-associated microbiota offers an additional valuable opportunity to increase global crop production and ensure future food and nutrient security. Nanomaterials (NMs) applied to agricultural crops can impact plant and soil microbiota, which offers valuable services to host plants, including the acquisition of nutrients, abiotic stress tolerance, and disease suppression. Dissecting the complex interactions between NMs and plants by integrating multi-omic approaches is providing new insights into how NMs can activate host responses and functionality as well as influence native microbial communities. Such nexus and moving beyond descriptive microbiome studies to hypothesis-driven research will foster microbiome engineering and open up opportunities for the development of synthetic microbial communities to provide agronomic solutions. Herein, we first summarize the significant role of NMs and the plant microbiome in crop productivity and then focus on NMs effects on plant-associated microbiota. We outline three urgent priority research areas and call for a transdisciplinary collaborative approach, involving plant scientists, soil scientists, environmental scientists, ecologists, microbiologists, taxonomists, chemists, physicists, and stakeholders, to advance nano-microbiome research. Detailed understanding of the nanomaterial-plant-microbiome interactions and the mechanisms underlying NMs-mediated shifts in the microbiome assembly and functions may help to exploit the services of both nano-objects and microbiota for next-generation crop health.

Can dark septate endophytic fungi (DSE) mobilize selectively inorganic soil phosphorus thereby promoting sorghum growth? A preliminary study / ¿Los hongos endófitos septados oscuros (DSE) pueden movilizar selectivamente el fósforo inorgánico y promover así el crecimiento del sorgo? Un estudio preliminar

Abstract Phosphate fertilizers tend to precipitate with soil components, affecting fertilization efficiency and causing negative environmental effects. Soil microorganisms have been used to solve this problem. However, the ability of dark septate endophytic fungi (DSE) to dissolve phosphates and increase crop yield are not well known. The activity of DSE fungi capable of solubilizing reagent grade phosphates was studied in a Typic Hapludoll (Hapludol típico). The effect of the fungi on the inorganic phosphorus fractions was evaluated and an experiment was conducted in pots with sorghum as a crop. No fungal structures were found in the roots. Curvularia sp. aerial biomass and root length increased; however, P concentration was not affected. Although the results are not conclusive, they represent an advance in the potential use of DSE fungi as P solubilizers to treat crop nutrition.

Resumen Los fertilizantes fosfatados tienden a precipitar con componentes del suelo, lo que afecta la eficiencia de la fertilización y causa efectos negativos. Para resolver este problema se han utilizado microorganismos del suelo. Sin embargo, no se conoce bien la capacidad de los hongos endófitos septados oscuros (ESO) para disolver fosfatos y aumentar el rendimiento de los cultivos. Se estudió en un hapludol típico (typic hapludoll) la actividad de hongos ESO capaces de solubilizar fosfatos de grado reactivo. Se evaluó el efecto de los hongos sobre las fracciones de fósforo inorgánico y se realizó un experimento en macetas con sorgo como cultivo. No se encontraron estructuras fúngicas en las raíces. Curvularia sp. aumentó la biomasa aérea y la longitud radical, pero la concentración de fósforo no se vio afectada. Aunque los resultados no son concluyentes, representan un avance en el uso potencial de hongos ESO como solubilizadores de fósforo para tratar la nutrición de cultivos.

Can dark septate endophytic fungi (DSE) mobilize selectively inorganic soil phosphorus thereby promoting sorghum growth? A preliminary study.

Phosphate fertilizers tend to precipitate with soil components, affecting fertilization efficiency and causing negative environmental effects. Soil microorganisms have been used to solve this problem. However, the ability of dark septate endophytic fungi (DSE) to dissolve phosphates and increase crop yield are not well known. The activity of DSE fungi capable of solubilizing reagent grade phosphates was studied in a Typic Hapludoll (Hapludol típico). The effect of the fungi on the inorganic phosphorus fractions was evaluated and an experiment was conducted in pots with sorghum as a crop. No fungal structures were found in the roots. Curvularia sp. aerial biomass and root length increased; however, P concentration was not affected. Although the results are not conclusive, they represent an advance in the potential use of DSE fungi as P solubilizers to treat crop nutrition.

Plant organ- and growth stage-diversity of endophytic bacteria with potential as biofertilisers isolated from wheat (Triticum aestivum L.).

BACKGROUND: Chemical fertilisers are extensively used for crop production, which may cause soil deterioration and water pollution. Endophytic bacteria with plant-growth-promoting (PGP) activities may provide a solution to sustainably improve crop yields, including in-demand staples such as wheat. However, the diversity of the PGP endophytic bacteria in wheat across plant organs and growth stages has not been thoroughly characterised. RESULTS: Here, we report the isolation of endophytic bacteria from root, stem, leaf and seed of three winter wheat varieties at tillering, jointing, heading and seed-filling growth stages that were identified via 16S rRNA gene sequence analysis. Strains were screened for indole-3-acetic acid (IAA) production, potassium and phosphate solubilisation and the ability to grow on a nitrogen-free medium. Strain's capacity to stimulate various plant growth parameters, such as dry root weight, dry above-ground parts weight and plant height, was evaluated in pot trials. A total of 127 strains were randomly selected from 610 isolated endophytic bacterial cultures, representing ten genera and 22 taxa. Some taxa were organ-specific; others were growth-stage-specific. Bacillus aryabhattai, B. stratosphericus, Leclercia adecarboxylata and Pseudomonas oryzihabitans were detected as wheat endophytes for the first time. The IAA production, inorganic phosphorous solubilisation, organic phosphorus solubilisation, potassium solubilisation and growth on N-free medium were detected in 45%, 29%, 37%, 2.4% and 37.8% of the 127 strains, respectively. In pot trials, each strain showed variable effects on inoculated wheat plants regarding the evaluated growth parameters. CONCLUSIONS: Wheat endophytic bacteria showed organ- and growth-stage diversity, which may reflect their adaptations to different plant tissues and seasonal variations, and differed in their PGP abilities. Bacillus was the most predominant bacterial taxa isolated from winter wheat plants. Our study confirmed wheat root as the best reservoir for screening endophytic bacteria with potential as biofertilisers.

The physio-chemical properties and applications of 2D nanomaterials in agricultural and environmental sustainability.

Global hunger and nutritional deficiency demand the advancement of existing and conventional approaches to food production. The application of nanoenabled strategies in agriculture has opened up new avenues for enhancing crop yield and productivity. Recently, two-dimensional (2D) nanomaterials (NMs) have manifested new possibilities for increasing food production and nutrition. Graphene nanosheets, the 2D form of graphene has been exemplary in enhancing the loading capacity of agro-active ingredients, their target-specific delivery, bioavailability, and controlled release with slow degradation, resulting in the increased shelf-life/active time of the agro-active components. Also, the development of novel formulations/composites of MXenes and Transition Metal Dichalcogenides (TMDs) can foster plant growth, metabolism, crop production, protection and improvement of soil quality. Additionally, the 2D NM-based biosensors can monitor the nutrient levels and other parameters affecting agronomical traits in plants. This review provides an insight into the details of 2D NM synthesis and functionalization methods. Notably, the review highlights the broad-range of 2D NM applications and their suitability in the development of nanotechnology-based agriformulations. The 2D NM-based derivatives have shown immense potential in enhancing the pedologic parameters, crop productivity, pest-protection and nutritional value. Thus, assisting in achieving food and environmental sustainability goals.

Smart Glass Film Reduced Ascorbic Acid in Red and Orange Capsicum Fruit Cultivars without Impacting Shelf Life.

Smart Glass Film (SGF) is a glasshouse covering material designed to permit 80% transmission of photosynthetically active light and block heat-generating solar energy. SGF can reduce crop water and nutrient consumption and improve glasshouse energy use efficiency yet can reduce crop yield. The effect of SGF on the postharvest shelf life of fruits remains unknown. Two capsicum varieties, Red (Gina) and Orange (O06614), were cultivated within a glasshouse covered in SGF to assess fruit quality and shelf life during the winter season. SGF reduced cuticle thickness in the Red cultivar (5%) and decreased ascorbic acid in both cultivars (9-14%) without altering the overall morphology of the mature fruits. The ratio of total soluble solids (TSSs) to titratable acidity (TA) was significantly higher in Red (29%) and Orange (89%) cultivars grown under SGF. The Red fruits had a thicker cuticle that reduced water loss and extended shelf life when compared to the Orange fruits, yet neither water loss nor firmness were impacted by SGF. Reducing the storage temperature to 2 °C and increasing relative humidity to 90% extended the shelf life in both cultivars without evidence of chilling injury. In summary, SGF had minimal impact on fruit development and postharvest traits and did not compromise the shelf life of mature fruits. SGF provides a promising technology to block heat-generating solar radiation energy without affecting fruit ripening and marketable quality of capsicum fruits grown during the winter season.

Psychrophilic Bacterial Phosphate-Biofertilizers: A Novel Extremophile for Sustainable Crop Production under Cold Environment.

Abiotic stresses, including low-temperature environments, adversely affect the structure, composition, and physiological activities of soil microbiomes. Also, low temperatures disturb physiological and metabolic processes, leading to major crop losses worldwide. Extreme cold temperature habitats are, however, an interesting source of psychrophilic and psychrotolerant phosphate solubilizing bacteria (PSB) that can ameliorate the low-temperature conditions while maintaining their physiological activities. The production of antifreeze proteins and expression of stress-induced genes at low temperatures favors the survival of such organisms during cold stress. The ability to facilitate plant growth by supplying a major plant nutrient, phosphorus, in P-deficient soil is one of the novel functional properties of cold-tolerant PSB. By contrast, plants growing under stress conditions require cold-tolerant rhizosphere bacteria to enhance their performance. To this end, the use of psychrophilic PSB formulations has been found effective in yield optimization under temperature-stressed conditions. Most of the research has been done on microbial P biofertilizers impacting plant growth under normal cultivation practices but little attention has been paid to the plant growth-promoting activities of cold-tolerant PSB on crops growing in low-temperature environments. This scientific gap formed the basis of the present manuscript and explains the rationale for the introduction of cold-tolerant PSB in competitive agronomic practices, including the mechanism of solubilization/mineralization, release of biosensor active biomolecules, molecular engineering of PSB for increasing both P solubilizing/mineralizing efficiency, and host range. The impact of extreme cold on the physiological activities of plants and how plants overcome such stresses is discussed briefly. It is time to enlarge the prospects of psychrophilic/psychrotolerant phosphate biofertilizers and take advantage of their precious, fundamental, and economical but enormous plant growth augmenting potential to ameliorate stress and facilitate crop production to satisfy the food demands of frighteningly growing human populations. The production and application of cold-tolerant P-biofertilizers will recuperate sustainable agriculture in cold adaptive agrosystems.

Open Data to Support Agricultural Diversification (version October 2020).

Following the development of a database that was specifically designed to store value chain information, particularly for underutilised crops, this article describes the data that are currently stored in the database and accessible through its web portal. The data includes various datasets on utilisation status, agro-ecological requirements and season lengths, potential yield and nutritional composition of crops. The data are stored in the form of tables with fixed data elements (column attributes). This article outlines the standard procedures (SOPs) that were developed in-house for data collection, metadata creation and data curation. These processes were used to ensure the quality and reusability of the data that is made available publicly through the database interface. Various statistics and example visualisations are provided to demonstrate the significance of such data for developing solutions for sustainable agricultural diversification.

Seed Biofortification by Engineered Nanomaterials: A Pathway To Alleviate Malnutrition?

Micronutrient deficiencies in global food chains are a significant cause of ill health around the world, particularly in developing countries. Agriculture is the primary source of nutrients required for sound health, and as the population has continued to grow, the agricultural sector has come under pressure to improve crop production, in terms of both quantity and quality, to meet the global demands for food security. The use of engineered nanomaterial (ENM) has emerged as a promising technology to sustainably improve the efficiency of current agricultural practices as well as overall crop productivity. One promising approach that has begun to receive attention is to use ENM as seed treatments to biofortify agricultural crop production and quality. This review highlights the current state of the science for this approach as well as critical knowledge gaps and research needs that must be overcome to optimize the sustainable application of nano-enabled seed fortification approaches.

Organic Amendments for Pathogen and Nematode Control.

The loss of methyl bromide as a soil fumigant and minimal advances in the development and registration of new chemical fumigants has resulted in a resurgence of interest in the application of organic amendments (OAs) for soilborne plant pathogen and plant-parasitic nematode management. Significant progress has been made in the characterization of OAs, application of strategies for their use, and elucidation of mechanisms by which they suppress soilborne pests. Nonetheless, their utility is limited by the variability of disease control, expense, and the logistics of introducing them into crop production systems. Recent advances in molecular techniques have led to significant progress in the elucidation of the role of bacteria and fungi and their metabolic products on disease suppression with the addition of OAs. Biosolarization and anaerobic soil disinfestation, developed to manipulate systems and favor beneficial microorganisms to maximize their impact on plant pathogens, are built on a strong historical research foundation in OAs and the physical, chemical, and biological characteristics of disease-suppressive soils. This review focuses on recent applications of OAs and their potential for the management of soilborne plant pathogens and plant-parasitic nematodes, with emphasis primarily on annual fruit and vegetable production systems.

Remotely sensed vegetation indices for crop nutrition mapping.

BACKGROUND: Spectral reflectance measurements and vegetation indices have been used widely to monitor plant nutritional status. Remote sensing methods are very fast, convenient, and non-destructive techniques for estimating crop nutrition indices. With the rapid development of remote sensing satellites, unmanned aerial vehicles, and the Internet of Things, remote sensing will increasingly be used in crop nutrition diagnosis. This can lead to lower operating costs for fertilization and can minimize loss of productivity. RESULTS: In this study, satellite images were used for 2 years to evaluate the use of vegetation indices for crop nutrition mapping, in two regions, located in the cities of Ray and Karaj. For each farm, eight reference points in each year were selected to determine the crop nutrition status for model development and accuracy assessment. Then, ten spectral vegetation indices were used to calculate the crop nutrition content at mid-season and at the end of the season. The results indicated that transformed chlorophyll absorption in reflectance index (TCARI) and modified chlorophyll absorption in reflectance index (MCARI) had the highest R2 and the lowest RMSE values, respectively (R2 TCARI = 0.83, RMSETCARI = 12.47 kg ha-1 and R2 MCARI = 0.75 and RMSEMCARI = 14.47 kg ha-1 ). CONCLUSION: The performance of TCARI and MCARI was strong across the two farms and allowed the creation of highly accurate crop nutrition maps. In conclusion, the use of the near infra-red and red-edge bands in mid-season led to better results than vegetation indices calculated at the end of the season or that do not included the red-edge band. © 2020 Society of Chemical Industry.

Acrylamide in food: Progress in and prospects for genetic and agronomic solutions.

Acrylamide is a processing contaminant and Group 2a carcinogen that was discovered in foodstuffs in 2002. Its presence in a range of popular foods has become one of the most difficult problems facing the food industry and its supply chain. Wheat, rye and potato products are major sources of dietary acrylamide, with biscuits, breakfast cereals, bread (particularly toasted), crispbread, batter, cakes, pies, French fries, crisps and snack products all affected. Here we briefly review the history of the issue, detection methods, the levels of acrylamide in popular foods and the risk that dietary acrylamide poses to human health. The pathways for acrylamide formation from free (non-protein) asparagine are described, including the role of reducing sugars such as glucose, fructose and maltose and the Maillard reaction. The evolving regulatory situation in the European Union and elsewhere is discussed, noting that food businesses and their suppliers must plan to comply not only with current regulations but with possible future regulatory scenarios. The main focus of the review is on the genetic and agronomic approaches being developed to reduce the acrylamide-forming potential of potatoes and cereals and these are described in detail, including variety selection, plant breeding, biotechnology and crop management. Obvious targets for genetic interventions include asparagine synthetase genes, and the asparagine synthetase gene families of different crop species are compared. Current knowledge on crop management best practice is described, including maintaining optimum storage conditions for potatoes and ensuring sulphur sufficiency and disease control for wheat.

Molecular Evolution and Interaction of Membrane Transport and Photoreception in Plants.

Light is a vital regulator that controls physiological and cellular responses to regulate plant growth, development, yield, and quality. Light is the driving force for electron and ion transport in the thylakoid membrane and other membranes of plant cells. In different plant species and cell types, light activates photoreceptors, thereby modulating plasma membrane transport. Plants maximize their growth and photosynthesis by facilitating the coordinated regulation of ion channels, pumps, and co-transporters across membranes to fine-tune nutrient uptake. The signal-transducing functions associated with membrane transporters, pumps, and channels impart a complex array of mechanisms to regulate plant responses to light. The identification of light responsive membrane transport components and understanding of their potential interaction with photoreceptors will elucidate how light-activated signaling pathways optimize plant growth, production, and nutrition to the prevailing environmental changes. This review summarizes the mechanisms underlying the physiological and molecular regulations of light-induced membrane transport and their potential interaction with photoreceptors in a plant evolutionary and nutrition context. It will shed new light on plant ecological conservation as well as agricultural production and crop quality, bringing potential nutrition and health benefits to humans and animals.

Nitrogen uptake and transfer in a soybean/maize intercropping system in the karst region of southwest China.

Nitrogen (N) deficiency occurs in over 80% of karst soil of southwest China, which restricts regional agricultural production. To test whether N fixed by legumes becomes available to nonfixing companion species, N fluxes between soybean and maize under no, partial, and total restriction of root contact were measured on a karst site in southwest China. N content and its transfer between soybean and maize intercrops were explored in a 2-year plot experiment, with N movement between crops monitored using 15N isotopes. Mesh barrier (30 µm) and no restrictions barrier root separation increased N uptake of maize by 1.28%-3.45% and 3.2%-3.45%, respectively. N uptake by soybean with no restrictions root separation was 1.23 and 1.56 times higher than that by mesh and solid barriers, respectively. In the unrestricted root condition, N transfer from soybean to maize in no restrictions barrier was 2.34-3.02 mg higher than that of mesh barrier. Therefore, it was implied that soybean/maize intercropping could improve N uptake and transfer efficiently in the karst region of southwest China.

Effects of abiotic stress and crop management on cereal grain composition: implications for food quality and safety.

The effects of abiotic stresses and crop management on cereal grain composition are reviewed, focusing on phytochemicals, vitamins, fibre, protein, free amino acids, sugars, and oils. These effects are discussed in the context of nutritional and processing quality and the potential for formation of processing contaminants, such as acrylamide, furan, hydroxymethylfurfuryl, and trans fatty acids. The implications of climate change for cereal grain quality and food safety are considered. It is concluded that the identification of specific environmental stresses that affect grain composition in ways that have implications for food quality and safety and how these stresses interact with genetic factors and will be affected by climate change needs more investigation. Plant researchers and breeders are encouraged to address the issue of processing contaminants or risk appearing out of touch with major end-users in the food industry, and not to overlook the effects of environmental stresses and crop management on crop composition, quality, and safety as they strive to increase yield.

Phosphorus application and elevated CO2 enhance drought tolerance in field pea grown in a phosphorus-deficient vertisol.

BACKGROUND AND AIMS: Benefits to crop productivity arising from increasing CO2 fertilization may be offset by detrimental effects of global climate change, such as an increasing frequency of drought. Phosphorus (P) nutrition plays an important role in crop responses to water stress, but how elevated CO2 (eCO2) and P nutrition interact, especially in legumes, is unclear. This study aimed to elucidate whether P supply improves plant drought tolerance under eCO2. METHODS: A soil-column experiment was conducted in a free air CO2 enrichment (SoilFACE) system. Field pea (Pisum sativum) was grown in a P-deficient vertisol, supplied with 15 mg P kg(-1) (deficient) or 60 mg P kg(-1) (adequate for crop growth) and exposed to ambient CO2 (aCO2; 380-400 ppm) or eCO2 (550-580 ppm). Drought treatments commenced at flowering. Measurements were taken of soil and leaf water content, photosynthesis, stomatal conductance, total soluble sugars and inorganic P content (Pi). KEY RESULTS: Water-use efficiency was greatest under eCO2 when the plants were supplied with adequate P compared with other treatments irrespective of drought treatment. Elevated CO2 decreased stomatal conductance and transpiration rate, and increased the concentration of soluble sugars and relative water contents in leaves. Adequate P supply increased concentrations of soluble sugars and Pi in drought-stressed plants. Adequate P supply but not eCO2 increased root length distribution in deeper soil layers. CONCLUSIONS: Phosphorus application and eCO2 interactively enhanced periodic drought tolerance in field pea as a result of decreased stomatal conductance, deeper rooting and high Pi availability for carbon assimilation in leaves.

In situ analysis of foliar zinc absorption and short-distance movement in fresh and hydrated leaves of tomato and citrus using synchrotron-based X-ray fluorescence microscopy.

BACKGROUND AND AIMS: Globally, zinc deficiency is one of the most important nutritional factors limiting crop yield and quality. Despite widespread use of foliar-applied zinc fertilizers, much remains unknown regarding the movement of zinc from the foliar surface into the vascular structure for translocation into other tissues and the key factors affecting this diffusion. METHODS: Using synchrotron-based X-ray fluorescence microscopy (µ-XRF), absorption of foliar-applied zinc nitrate or zinc hydroxide nitrate was examined in fresh leaves of tomato (Solanum lycopersicum) and citrus (Citrus reticulatus). KEY RESULTS: The foliar absorption of zinc increased concentrations in the underlying tissues by up to 600-fold in tomato but only up to 5-fold in citrus. The magnitude of this absorption was influenced by the form of zinc applied, the zinc status of the treated leaf and the leaf surface to which it was applied (abaxial or adaxial). Once the zinc had moved through the leaf surface it appeared to bind strongly, with limited further redistribution. Regardless of this, in these underlying tissues zinc moved into the lower-order veins, with concentrations 2- to 10-fold higher than in the adjacent tissues. However, even once in higher-order veins, the movement of zinc was still comparatively limited, with concentrations decreasing to levels similar to the background within 1-10 mm. CONCLUSIONS: The results advance our understanding of the factors that influence the efficacy of foliar zinc fertilizers and demonstrate the merits of an innovative methodology for studying foliar zinc translocation mechanisms.