Vinod Saharan

Synthesis of chitosan based nanoparticles and their in vitro evaluation against phytopathogenic fungi

The main aim of present study was to prepare chitosan, chitosan-saponin and Cu-chitosan nanoparticles to evaluate their in vitro antifungal activities. Various nanoparticles were prepared using ionic gelation method by interaction of chitosan, sodium tripolyphosphate, saponin and Cu ions. Their particle size, polydispersity index, zeta potential and structures were confirmed by DLS, FTIR, TEM and SEM. The antifungal properties of nanoparticles against phytopathogenic fungi namely Alternaria alternata, Macrophomina phaseolina and Rhizoctonia solani were investigated at various concentrations ranging from 0.001 to 0.1%. Among the various formulations of nanoparticles, Cu-chitosan nanoparticles were found most effective at 0.1% concentration and showed 89.5, 63.0 and 60.1% growth inhibition of A. alternata, M. phaseolina and R. solani, respectively in in vitro model. At the same concentration, Cu-chitosan nanoparticles also showed maximum of 87.4% inhibition rate of spore germination of A. alternata. Chitosan nanoparticles showed the maximum growth inhibitory effects (87.6%) on in vitro mycelial growth of M. phaseolina at 0.1% concentration. From our study it is evident that chitosan based nanoparticles particularly chitosan and Cu-chitosan nanoparticles have tremendous potential for further field screening towards crop protection.

Synthesis and in vitro antifungal efficacy of Cu–chitosan nanoparticles against pathogenic fungi of tomato

Cu-chitosan nanoparticles were synthesized and evaluated for their growth promotory and antifungal efficacy in tomato (Solanum lycopersicum Mill). Physico-chemical characterization of the developed Cu-chitosan nanoparticles was carried out by DLS, FTIR, TEM, SEM-EDS and AAS. The study highlighted the stability and porous nature of Cu-chitosan nanoparticles. Laboratory synthesized nanoparticles showed substantial growth promotory effect on tomato seed germination, seedling length, fresh and dry weight at 0.08, 0.10 and 0.12% level. At 0.12% concentration these nanoparticles caused 70.5 and 73.5% inhibition of mycelia growth and 61.5 and 83.0% inhibition of spore germination in Alternaria solani and Fusarium oxysporum, respectively, in an in vitro model. In pot experiments, 0.12% concentration of Cu-chitosan nanoparticles was found most effective in percentage efficacy of disease control (PEDC) in tomato plants with the values of 87.7% in early blight and 61.1% in Fusarium wilt. The overall results confirm the significant growth promotory as well as antifungal capabilities of Cu-chitosan nanoparticles. Our model demonstrated the synthesis of Cu-chitosan nanoparticles and open up the possibility to use against fungal disease at field level. Further, developed porous nanomaterials could be exploited for delivery of agrochemicals.

Cu-Chitosan Nanoparticle Mediated Sustainable Approach To Enhance Seedling Growth in Maize by Mobilizing Reserved Food.

Food crop seedlings often have susceptibility to various abiotic and biotic stresses. Therefore, in the present study, we investigated the impact of Cu-chitosan nanoparticles (NPs) on physiological and biochemical changes during maize seedling growth. Higher values of percent germination, shoot and root length, root number, seedling length, fresh and dry weight, and seed vigor index were obtained at 0.04-0.12% concentrations of Cu-chitosan NPs as compared to water, CuSO4, and bulk chitosan treatments. Cu-chitosan NPs at the same concentrations induced the activities of α-amylase and protease enzymes and also increased the total protein content in germinating seeds. The increased activities of α-amylase and protease enzymes corroborated with decreased content of starch and protein, respectively, in the germinating seeds. Cu-chitosan NPs at 0.16% and CuSO4 at 0.01% concentrations showed inhibitory effect on seedling growth. The observed results on seedling growth could be explained by the toxicity of excess Cu and growth promotory effect of Cu-chitosan NPs. Physiological and biochemical studies suggest that Cu-chitosan NPs enhance the seedling growth of maize by mobilizing the reserved food, primarily starch, through the higher activity of α-amylase.

Cu-chitosan nanoparticle boost defense responses and plant growth in maize ( Zea mays L.)

In agriculture, search for biopolymer derived materials are in high demand to replace the synthetic agrochemicals. In the present investigation, the efficacy of Cu-chitosan nanoparticles (NPs) to boost defense responses against Curvularia leaf spot (CLS) disease of maize and plant growth promotry activity were evaluated. Cu-chitosan NPs treated plants showed significant defense response through higher activities of antioxidant (superoxide dismutase and peroxidase) and defense enzymes (polyphenol oxidase and phenylalanine ammonia-lyase). Significant control of CLS disease of maize was recorded at 0.04 to 0.16% of Cu-chitosan NPs treatments in pot and 0.12 to 0.16% of NPs treatments in field condition. Further, NPs treatments exhibited growth promotry effect in terms of plant height, stem diameter, root length, root number and chlorophyll content in pot experiments. In field experiment, plant height, ear length, ear weight/plot, grain yield/plot and 100 grain weight were enhanced in NPs treatments. Disease control and enhancement of plant growth was further enlightened through Cu release profile of Cu-chitosan NPs. This is an important development in agriculture nanomaterial research where biodegradable Cu-chitosan NPs are better compatible with biological control as NPs “mimic” the natural elicitation of the plant defense and antioxidant system for disease protection and sustainable growth.

Nanofertilizer for Precision and Sustainable Agriculture: Current State and Future Perspectives

The increasing food demand as a result of the rising global population has prompted the large-scale use of fertilizers. As a result of resource constraints and low use efficiency of fertilizers, the cost to the farmer is increasing dramatically. Nanotechnology offers great potential to tailor fertilizer production with the desired chemical composition, improve the nutrient use efficiency that may reduce environmental impact, and boost the plant productivity. Furthermore, controlled release and targeted delivery of nanoscale active ingredients can realize the potential of sustainable and precision agriculture. A review of nanotechnology-based smart and precision agriculture is discussed in this paper. Scientific gaps to be overcome and fundamental questions to be answered for safe and effective development and deployment of nanotechnology are addressed.

Viral, Fungal and Bacterial Disease Resistance in Transgenic Plants

Continuing attention is being devoted to the development of substitute strategies in plant-disease management and reducing dependency on synthetic chemicals. Viral, fungal and bacterial diseases are unquestionably the most versatile for environmental adaption and in the destruction of plant growth. Among the strategies, resistance breeding has generated proven data and been exploited in depth. However, conventional methods alone are not sufficient to control the novel races of viral, fungal and bacterial pathogens in crops due to a scarcity in required crop variations. The current situation encourages the search for variation against biotic stress through identification of genes across species. Over the last two decades, significant efforts have been initiated in plant-disease management via genetic engineering. In addition, several molecular techniques have emerged to disentangle multifaceted plant-pathogen systems and associated disease-resistance candidate genes. Besides describing many promising candidate genes from viruses, fungi and bacteria, numerous plant disease-resistance genes have been identified and evaluated in crop improvement programs by transformation. Advancement in plant transformation techniques enables transferring useful genes for the rational creation of disease-resistant plants. Success has been achieved in transgenic crops against various diseases of important crop plants. This chapter describes genetically engineered plants and their resistant to viral, fungal and bacterial pathogens.

Engineered chitosan based nanomaterials: Bioactivities, mechanisms and perspectives in plant protection and growth

Excessive use of agrochemicals for enhancing crop production and its protection posed environmental and health concern. Integration of advanced technology is required to realize the concept of precision agriculture by minimizing the input of pesticides and fertilizers per unit while improving the crop productivity. Notably, chitosan based biodegradable nanomaterials (NMs) including nanoparticles, nanogels and nanocomposites have eventually proceeded as a key choice in agriculture due to their inimitable properties like antimicrobial and plant growth promoting activities. The foreseeable role of chitosan based NMs in plants might be in achieving sustainable plant growth through boosting the intrinsic potential of plants. In-spite of the fact that chitosan based NMs abode immense biological activities in plants, these materials have not yet been widely adopted in agriculture due to poor understanding of their bioactivity and modes of action towards pathogenic microbes and in plant protection and growth. To expedite the anticipated claims of chitosan based NMs, it is imperative to line up all the possible bioactivities which denote for sustainable agriculture. Herein, we have highlighted, in-depth, various chitosan based NMs which have been used in plant growth and protection mainly against fungi, bacteria and viruses and have also explained their modes of action.

Synthesis, Characterization, and Application of Chitosan Nanomaterials Loaded with Zinc and Copper for Plant Growth and Protection

In recent years, chitosan-based nanomaterials have been the most researched biomaterials in the field of medical, pharmaceutical, and agriculture. Metal-based chitosan nanomaterials have attracted much attention due to its dual activity as plant growth promoter and plant protection agent. In addition, chitosan encapsulated metals are less toxic due to slow release phenomenon and showed long-lasting effect in plants. Blending of Zn and Cu with nanochitosan has additional advantages of providing nutrition to plants and help in vigor growth of plant for further protection from abiotic and biotic stress. In addition, Cu/Zn chitosan nanoparticles have been successfully tested against many plant pathogenic bacteria and fungi. Moreover, Cu/Zn chitosan nanoparticles are involved in inducing amylase and protease enzymes related to mobilization of food for seed germination. A recent study revealed that Zn/Cu chitosan nanomaterials are enhancing defense enzymes of plant which protect them from diseases. In this chapter, we have explained thoroughly the synthesis of Cu and Zn chitosan NPs, their characterization and applications in plant growth, and protection.

Inactivation thermodynamics and iso-kinetic profiling for evaluating operational suitability of milk clotting enzyme immobilized in composite polymer matrix.

Milk clotting enzyme (MCE) was immobilized in alginate-pectate interwoven gel with the yield of 73%. The encapsulated enzyme retained most of the protein load while soluble enzyme lost major proportion of activity after few hours. The immobilized enzyme showed high operational stability by retaining 40% activity even after 10 uses. The narrow optimal working pH of soluble enzyme changed to a broader range after encapsulation and a shift in optimum temperature from 45 to 50°C was also recorded for encapsulated enzyme. Studies on isokinetic temperature showed that immobilized enzyme is more thermo-stable at higher temperature. Immobilization, therefore, not only improved the catalytic properties and stability but also its suitability in food processes like cheese preparation with reduced cost and time.

Thymol nanoemulsion exhibits potential antibacterial activity against bacterial pustule disease and growth promotory effect on soybean

An antibacterial and plant growth promoting nanoemulsion was formulated using thymol, an essential oil component of plant and Quillaja saponin, a glycoside surfactant of Quillaja tree. The emulsion was prepared by a sonication method. Fifty minutes of sonication delivered a long term stable thymol nanoemulsion which was characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), cryogenic-field emission scanning electron microscopy (Cryo-FESEM) and fourier transform infra-red (FTIR) spectroscopy. Creaming index, pH and dilution stability were also studied for deliberation of its practical applications. The nanoemulsion (0.01–0.06%, v/v) showed substantial in vitro growth inhibition of Xanthomonas axonopodis pv. glycine of soybean (6.7-0.0 log CFU/ml). In pot experiments, seed treatment and foliar application of the nanoemulsion (0.03–0.06%, v/v) significantly lowered the disease severity (DS) (33.3–3.3%) and increased percent efficacy of disease control (PEDC) (54.9–95.4%) of bacterial pustule in soybean caused by X. axonopodis pv. glycine. Subsequently, significant enhancements of plant growth were also recorded in plants treated with thymol nanoemulsion. This is the first report of a thymol based nanoemulsion obtained using Quillaja saponin as a surfactant. Our study claims that nano scale thymol could be a potential antimicrobial and plant growth promoting agent for agriculture.