Current trends and challenges in the synthesis and applications of chitosan-based nanocomposites for plants: A review.

Chitosan, a low-cost and multipurpose polymer with numerous desired physicochemical and biological properties has been tested for various applications in agriculture, pharmacy, and biomedicine industries. The availability of functional groups along the backbone makes chitosan readily available for other polymers and metal ions to form bio-nanocomposites. Different types of chitosan-based nanocomposites have been designed and tested for the enhancement of chitosan efficiency and ultimately widening the application areas of chitosan in plants. These nanocomposites serve different purposes such as eliciting plant's defence systems against different threats (pathogen attack), antimicrobial agent against bacteria, fungi and viruses, enhancement of nutrient uptake by plants, control release of micro/macronutrients, fungicides and herbicides. In this review, an extensive outlook has been provided (mainly in the last five years) to recent trends and advances in the fabrication and application of chitosan-based composites. Finally, current challenges and future development opportunities of chitosan-based nanocomposites for plants are discussed.

Latest generation of halogen-containing pesticides.

Agriculture is confronted with enormous challenges, from production of enough high-quality food to water use, environmental impacts and issues combined with a continually growing world population. Modern agricultural chemistry has to support farmers by providing innovative agrichemicals, used in applied agriculture. In this context, the introduction of halogen atoms into an active ingredient is still an important tool to modulate the properties of new crop protection compounds. Since 2010, around 96% of the launched products (herbicides, fungicides, insecticides/acaricides and nematicides) contain halogen atoms. The launched nematicides contain the largest number of halogen atoms, followed by insecticides/acaricides, herbicides and fungicides. In this context, fungicides and herbicides contain in most cases fluorine atoms, whereas nematicides and insecticides contain in most cases 'mixed' halogen atoms, for example chlorine and fluorine. This review gives an overview of the latest generation of halogen-containing pesticides launched over the past 6 years and describes current halogen-containing development candidates. © 2017 Society of Chemical Industry.

Efficient Approach To Discover Novel Agrochemical Candidates: Intermediate Derivatization Method.

Intensive competition of intellectual property, easy development of agrochemical resistance, and stricter regulations of environmental concerns make the successful rate for agrochemical discovery extremely lower using traditional agrochemical discovery methods. Therefore, there is an urgent need to find a novel approach to guide agrochemical discovery with high efficiency to quickly keep pace with the changing market. On the basis of these situations, here we summarize the intermediate derivatization method (IDM) between conventional methods in agrochemicals and novel ones in pharmaceuticals. This method is relatively efficient with short time in discovery phase, reduced cost, especially good innovated structure, and better performance. In this paper, we summarize and illustrate "what is the IDM" and "why to use" and "how to use" it to accelerate the discovery of new biologically active molecules, focusing on agrochemicals. Furthermore, we display several research projects in our novel agrochemical discovery programs with improved success rate under guidance of this strategy in recent years.

Controlled-release fertilizer prepared using a biodegradable aliphatic copolyester of poly(butylene succinate) and dimerized fatty acid.

The preparation and characterization of a controlled-release multicomponent (NPK) fertilizer with the coating layer consisting of a biodegradable copolymer of poly(butylene succinate) and a butylene ester of dilinoleic acid (PBS/DLA) is reported. The morphology and structure of the resulting polymer-coated materials and the thickness of the covering layers were examined using X-ray diffraction and scanning electron microscopy coupled with energy dispersive X-ray analysis. The mechanical properties of these materials were determined with a strength-testing machine. Nutrient release was measured in water using spectrophotometry, potentiometry, and conductivity methods. The results of the nutrient release experiments from these polymer-coated materials were compared with the requirements for controlled-release fertilizers. A conceptual model is presented describing the mechanism of nutrient release from the materials prepared in this study. This model is based on the concentrations of mineral components inside the water-penetrated fertilizer granules, the diffusion properties of the nutrients in water, and a diffusion coefficient through the polymer layer. The experimental kinetic data on nutrient release were interpreted using the sigmoidal model equation developed in this study.

Chilean flour and wheat grain: tracing their origin using near infrared spectroscopy and chemometrics.

Instrumental techniques such a near-infrared spectroscopy (NIRS) are used in industry to monitor and establish product composition and quality. As occurs with other food industries, the Chilean flour industry needs simple, rapid techniques to objectively assess the origin of different products, which is often related to their quality. In this sense, NIRS has been used in combination with chemometric methods to predict the geographic origin of wheat grain and flour samples produced in different regions of Chile. Here, the spectral data obtained with NIRS were analysed using a supervised pattern recognition method, Discriminat Partial Least Squares (DPLS). The method correctly classified 76% of the wheat grain samples and between 90% and 96% of the flour samples according to their geographic origin. The results show that NIRS, together with chemometric methods, provides a rapid tool for the classification of wheat grain and flour samples according to their geographic origin.

Challenges of formulation and quality of biofertilizers for successful inoculation.

The interest in biofertilizers is increasing and so is the potential for their use in sustainable agriculture. However, many of the products that are currently available worldwide are often of very poor quality, resulting in the loss of confidence from farmers. The formulation of an inoculant is a crucial multistep process that should result in one or several strains of microorganisms included in a suitable carrier, providing a safe environment to protect them from the often harsh conditions during storage and ensuring survival and establishment after introduction into soils. One of the key issues in formulation development and production is the quality control of the products, at each stage of the process. This review presents the different components and the major steps involved in the formulation of good quality biofertilizers, including the techniques used to assess the quality of the products following production. The quality of currently available inoculants is also reviewed, emphasizing the need for better quality control systems worldwide.

Tannin structural elucidation and quantitative ³¹P NMR analysis. 1. Model compounds.

Tannins and flavonoids are secondary metabolites of plants that display a wide array of biological activities. This peculiarity is related to the inhibition of extracellular enzymes that occurs through the complexation of peptides by tannins. Not only the nature of these interactions, but more fundamentally also the structure of these heterogeneous polyphenolic molecules are not completely clear. This first paper describes the development of a new analytical method for the structural characterization of tannins on the basis of tannin model compounds employing an in situ labeling of all labile H groups (aliphatic OH, phenolic OH, and carboxylic acids) with a phosphorus reagent. The ³¹P NMR analysis of ³¹P-labeled samples allowed the unprecedented quantitative and qualitative structural characterization of hydrolyzable tannins, proanthocyanidins, and catechin tannin model compounds, forming the foundations for the quantitative structural elucidation of a variety of actual tannin samples described in part 2 of this series.

Tannin structural elucidation and quantitative ³¹P NMR analysis. 2. Hydrolyzable tannins and proanthocyanidins.

An unprecedented analytical method that allows simultaneous structural and quantitative characterization of all functional groups present in tannins is reported. In situ labeling of all labile H groups (aliphatic and phenolic hydroxyls and carboxylic acids) with a phosphorus-containing reagent (Cl-TMDP) followed by quantitative ³¹P NMR acquisition constitutes a novel fast and reliable analytical tool for the analysis of tannins and proanthocyanidins with significant implications for the fields of food and feed analyses, tannery, and the development of natural polyphenolics containing products.

Biobased polymer composites derived from corn stover and feather meals as double-coating materials for controlled-release and water-retention urea fertilizers.

In this paper, we synthesized a biobased polyurethane using liquefied corn stover, isocyanate, and diethylenetriamine. The synthesized polyurethane was used as a coating material to control nitrogen (N) release from polymer-coated urea. A novel superabsorbent composite was also formulated from chicken feather protein (CFP), acrylic acid, and N,N'-methylenebisacrylamide and used as an outer coating material for water retention. We studied the N release characteristics and water-retention capability of the double-layer polymer-coated urea (DPCU) applied in both water and soils. The ear yields, dry matter accumulation, total N use efficiency and N leaching from a sweet corn soil-plant system under two different irrigation regimes were also investigated. Comparison of DPCU treatments with conventional urea fertilizer revealed that DPCU treatments reduced the N release rate and improved water retention capability. Evaluation of soil and plant characteristics within the soil-plant system revealed that DPCU application effectively reduced N leaching loss, improved total N use efficiency, and increased soil water retention capability.

Current challenges and trends in the discovery of agrochemicals.

Crop protection chemistry has come a long way from its "alchemic" beginnings in the late 19th century to a high-tech science that supports the sustainable production of food, feed, and fiber for a rapidly growing population. Cutting-edge developments in the design and synthesis of agrochemicals help to tackle today's challenges of weed and pest resistance, higher regulatory safety margins, and higher cost of goods with the invention of selective, environmentally benign, low use rate, and cost-effective active ingredients.

Synthesis and quantitative structure-activity relationship (QSAR) study of novel N-arylsulfonyl-3-acylindole arylcarbonyl hydrazone derivatives as nematicidal agents.

In continuation of our program aimed at the discovery and development of natural-product-based pesticidal agents, 54 novel N-arylsulfonyl-3-acylindole arylcarbonyl hydrazone derivatives were prepared, and their structures were well characterized by ¹H NMR, ¹³C NMR, HRMS, ESI-MS, and mp. Their nematicidal activity was evaluated against that of the pine wood nematode, Bursaphelenchus xylophilus in vivo. Among all of the derivatives, especially V-12 and V-39 displayed the best promising nematicidal activity with LC50 values of 1.0969 and 1.2632 mg/L, respectively. This suggested that introduction of R¹ and R² together as the electron-withdrawing substituents, R³ as the methyl group, and R4 as the phenyl with the electron-donating substituents could be taken into account for further preparation of these kinds of compounds as nematicidal agents. Six selected descriptors are a WHIM descriptor (E1m), two GETAWAY descriptors (R1m+ and R3m+), a Burden eigenvalues descriptor (BEHm8), and two edge-adjacency index descriptors (EEig05x and EEig13d). Quantitative structure-activity relationship (QSAR) studies demonstrated that the structural factors, such as molecular mass (a negative correlation with the bioactivity) and molecular polarity (a positive correlation with bioactivity), are likely to govern the nematicidal activities of these compounds. For this model, the correlation coefficient (R²(training set)), the leave-one-out cross-validation correlation coefficient (Q²(LOO)), and the 7-fold cross-validation correlation coefficient (Q²(7-fold)) were 0.791, 0.701, and 0.715, respectively. The external cross-validation correlation coefficient (Q²ext) and the root-mean-square error for the test set (RMSE(test set)) were 0.774 and 3.412, respectively. This study will pave the way for future design, structural modification, and development of indole derivatives as nematicidal agents.

Cell wall components of Leptosphaeria maculans enhance resistance of Brassica napus.

Preparations with elicitation activity were obtained from the mycelium of Leptosphaeria maculans , a fungal pathogen of oilseed rape (Brassica napus). Crude delipidated and deproteinized extract from fungal cell walls induced expression of pathogenesis related gene 1 (PR1), hydrogen peroxide accumulation, and enhanced resistance of B. napus plants toward infection by L. maculans. Elicitation activity significantly decreased after treatment of a crude extract with α- or ß-glucanase. Monosaccharide composition analysis of a crude extract purified by ion-exchange chromatography revealed glucose (∼58 mol %), mannose (∼22 mol %), and galactose (∼18 mol %) as the major sugars. FT-IR and NMR spectra confirmed the presence of both carbohydrate and polypeptide components in the purified product. Correlation NMR experiments defined trisaccharide bound to O-3 of serine residue α-D-Glcp-(1→2)-ß-D-Galf-(1→6)-α-D-Manp-(1→3)-L-Ser. Terminal α-D-Glcp and (1→6)-ß-D-glucan were also detected. The obtained results strongly support the conclusion that these carbohydrates induce defense response in B. napus plants.

Nematicidal activity of nonacosane-10-ol and 23a-homostigmast-5-en-3ß-ol isolated from the roots of Fumaria parviflora (Fumariaceae).

Two bioactive nematicidal phytochemicals, viz., nonacosane-10-ol and 23a-homostigmast-5-en-3ß-ol, were isolated from the n-hexane fraction of the roots of Fumaria parviflora through activity-guided isolation. The structures of the compounds were elucidated using ¹³C and ¹H nuclear magnetic resonance. Activity of the two compounds against eggs and juveniles (J2s) of Meloidogyne incognita was evaluated in vitro at the concentrations of 50, 100, 150, and 200 µg mL⁻¹. Over 120 h of incubation, the cumulative percent mortality and hatch inhibition of both of the compounds tested ranged from 20 to 100% and from 15 to 95.0%, respectively. In pot trials with tomato cultivar Riogrande, the two compounds, applied as soil drenches at the concentrations of 100, 200, and 300 mg/kg, significantly decreased the nematodes and plant growth parameters. Nonacosane-10-ol and 23a-homostigmast-5-en-3ß-ol reduced the numbers of galls (42.6 and 60.3), galling index (1.6 and 2.8), females per gram of root (37.3 and 57.0), eggs per gram of root (991.3 and 1273.0), reproduction factor (Rf) (0.1 and 0.2), and fresh root weight (14.33 and 17.0 g) at 300 mg/kg concentration and increased fresh shoot weight (49.0 and 48.4 g), dry shoot weight (28.0 and 25.3 g), and plant height (53.5 and 49.6 cm), respectively. These compounds could provide new insight in the search for novel nematicides against M. incognita.

Addressing the complexity and diversity of agricultural plant volatiles: a call for the integration of laboratory- and field-based analyses.

As the sophistication and sensitivity of chemical instrumentation increase, so does the number of applications. Correspondingly, new questions and opportunities for systems previously studied also arise. As with most plants, the emission of volatiles from agricultural products is complex and varies among commodities. Volatiles are indicative of characteristics such as food quality, cultivar type, phenological stage, and biotic and abiotic stressors; thus, their systematic and accurate evaluation is important. Early volatile analyses entailed removal of the sample matrix in question, transport to the laboratory, and subsequent investigation. More recently, scientists are moving the laboratory to the field to obtain realistic emission patterns of the sample in its natural environment. This perspective proposes that a methodical and collaborative approach to the complex relationship between volatiles and agricultural commodities and their various phenological stages, oxidative degradation products, and fungal contamination is needed in order to fully comprehend the sample and associated relationships as a whole. These methodical approaches should incorporate both in situ and ex situ investigations of the sample. Ultimately, there exists an opportunity for development of methodologies that integrate both laboratory- and field-based collection of volatiles to explore and address the complex biological interactions of agricultural systems.

Development of karanja oil based offset printing ink in comparison with linseed oil.

The conventional offset lithographic printing ink is mainly based on linseed oil. But in recent years, due to stiff competition from synthetic substitutes mainly from petroleum products, the crop production shrinks down to an unsustainable level, which increases the price of linseed oil. Though soyabean oil has replaced a major portion of linseed oil, it is also necessary to develop alternate cost effective vegetable oils for printing ink industry. The present study aims to evaluate the performance of karanja oil (Pongamia glabra) as an alternative of linseed oil in the formulation of offset printing ink because karanja oil is easily available in rural India. Physical properties of raw karanja oil are measured and compared with that of alkali refined linseed oil. Rosin modified phenolic resin based varnishes were made with linseed oil as well as with karanja oil and their properties are compared. Sheetfed offset inks of process colour yellow and cyan is chosen to evaluate the effect of karanja oil in ink properties. In conclusion, karanja oil can be accepted as an alternate vegetable oil source with its noticeable effect on print and post print properties with slower drying time on paper. However, the colour and odour of the oil will restrict its usage on offset inks.

Development of a rapid soil water content detection technique using active infrared thermal methods for in-field applications.

The aim of this study was to investigate the suitability of active infrared thermography and thermometry in combination with multivariate statistical partial least squares analysis as rapid soil water content detection techniques both in the laboratory and the field. Such techniques allow fast soil water content measurements helpful in both agricultural and environmental fields. These techniques, based on the theory of heat dissipation, were tested by directly measuring temperature dynamic variation of samples after heating. For the assessment of temperature dynamic variations data were collected during three intervals (3, 6 and 10 s). To account for the presence of specific heats differences between water and soil, the analyses were regulated using slopes to linearly describe their trends. For all analyses, the best model was achieved for a 10 s slope. Three different approaches were considered, two in the laboratory and one in the field. The first laboratory-based one was centred on active infrared thermography, considered measurement of temperature variation as independent variable and reported r = 0.74. The second laboratory-based one was focused on active infrared thermometry, added irradiation as independent variable and reported r = 0.76. The in-field experiment was performed by active infrared thermometry, heating bare soil by solar irradiance after exposure due to primary tillage. Some meteorological parameters were inserted as independent variables in the prediction model, which presented r = 0.61. In order to obtain more general and wide estimations in-field a Partial Least Squares Discriminant Analysis on three classes of percentage of soil water content was performed obtaining a high correct classification in the test (88.89%). The prediction error values were lower in the field with respect to laboratory analyses. Both techniques could be used in conjunction with a Geographic Information System for obtaining detailed information on soil heterogeneity.

Prevention of chloridazon and metribuzin pollution using lignin-based formulations.

The herbicides chloridazon and metribuzin, identified as groundwater pollutants, were incorporated in lignin-based granules with different sizes to obtain controlled release formulations (CRFs) and reduce water pollution risk. Kinetics release tests in water and soil showed that the release rate of both from CRFs diminished in comparison to technical products. A linear correlation was obtained between the time taken for 50% of the active ingredient to be released (T(50)) into water and granule size of the CRFs. Besides, a linear correlation was reached between T(50) values in water and soil. Mobility experiments carried out in calcareous soil show that the use of lignin-based CRFs reduces the presence of both herbicides in the leachate compared to the technical grade products. The set of experiments developed in this research can be useful to design, prepare and evaluate formulations with CR properties which can reduce the pollution derived from the use of herbicides.

Long-term sustainability of metal immobilization by soil amendments: cyclonic ashes versus lime addition.

A soil column leaching experiment was used to gain insight into the long-term metal immobilization capacity of cyclonic ashes (CAH) compared to lime (LIME). Twenty six years of rainfall were simulated. Initially, all amended soils were brought to an equal soil pH. This was done to obtain optimal conditions for the detection of metal immobilization mechanisms different from just a pH effect. During the simulation period, soil pH in all treatments decreased in parallel. However, the evolution of metal mobility and phytoavailability showed a clearly distinct pattern. The strong reduction in metal immobilizing efficiency observed in the lime treatment at the end of the simulation period was much less pronounced, or even absent, in the CAH treatments. Moreover, metal accumulation in plants grown on the CAH amended soil was significantly lower compared to the untreated and the lime treated soil. CAH + SS treatment delivered the strongest reductions in metal mobility and bioavailability.

Chemoinformatics-applications in food chemistry.

The aim of the present chapter is to present the current research and potential applications of chemoinformatics tools in food chemistry. First, the importance and variety of molecular descriptors and physicochemical properties is delineated, and then a survey and chemical space analysis of representative databases with emphasis on food-related ones is presented. A brief description of methods commonly used in molecular design, followed by examples in food chemistry are presented, such methods include similarity searching, pharmacophore modeling, quantitative structure-activity relationships (QSAR), and molecular docking. The relatedness to virtual screening is emphasized and the perspectives from this field are presented at the end.

Biomass compositional analysis for energy applications.

In its broadest definition, biomass can be described as all material that was or is a part of a living organism. For renewable energy applications, however, the definition of biomass is usually limited to include only materials that are plant-derived such as agricultural residues (e.g., wheat straw, corn stover) by-products of industrial processes (e.g., sawdust, sugar cane bagasse, pulp residues, distillers grains), or dedicated energy crops (e.g., switchgrass, sorghum, Miscanthus, short-rotation woody crops). This chapter describes analytical methods developed to measure plant components with an emphasis on the measurement of components that are important for biomass conversion. The methods described here can be viewed as a portfolio of analytical methods, with consistent assumptions and compatible sample preparation steps, selected for simplicity, robust application, and the ability to obtain a summative mass closure on most samples that accurately identifies greater than 95% of the mass of a plant biomass sample. The portfolio of methods has been successfully applied to a wide variety of biomass feedstock as well as liquid and solid fractions of both thermochemical pretreatment and enzymatic saccharification (1).