Zinc-functionalized thymol nanoemulsion for promoting soybean yield.

Herein, we report zinc-functionalized thymol nanoemulsion (Zn-TNE) by sonication method and its characterization by DLS, HR-TEM, FEG-SEM-EDS, Cryo-FESEM, FTIR and AAS studies. Zn-TNE treated seeds bestowed better seedling vigor index and higher activities of seed stored food mobilizing enzymes (α-amylase and protease). Foliar application of Zn-TNE (0.01-0.06%, v/v) enhanced defense-antioxidant enzymes activities, balanced reactive oxygen species, induced higher content of chlorophyll-a, b and higher lignin deposition in soybean plants. In the field, Zn-TNE application (0.02-0.06%, v/v) significantly controlled bacterial pustule disease (PEDC value 28-79%) and increased grain yield up to 16.6% as compared with bulk thymol application and up to 50% from control. Disease control and higher yield in soybean could be explained by diverse bioactivities of Zn-TNE in maintaining cellular homeostasis of soybean plants. Study shows that Zn-TNE can further be maneuvered for slow delivery of other micronutrients for higher crop yield.

Zinc encapsulated chitosan nanoparticle to promote maize crop yield.

Zinc deficient/or alkaline soil is globally widespread issue and cultivation of cereals in such soil results in severe depression in plant growth, higher disease incidence and lower grain yield. To address such problems, laboratory synthesized Zn-chitosan nanoparticles (NPs) were evaluated via seed priming and foliar application in maize plants. Zn-chitosan NPs (0.01-0.16%) showed strong in vitro antifungal and seedling growth promotry activities. Further, Zn-chitosan NPs exhibited significant disease control through strengthening of plant innate immunity by elevating antioxidant and defense enzymes, balancing of reactive oxygen species (ROS) and enhancing lignin accumulation. In field, seed treatment and foliar application of developed NPs (0.01-0.16%) significantly controlled Curvularia leaf spot (CLS) disease, increased grain yield from 20.5 to 39.8% and enriched the grain with zinc micronutrient from 41.27 to 62.21 µg/g dw. Results claim that Zn-chitosan NPs could be an effective growth promotry, disease controlling and micronutrient fortifying agent in maize crop.

Salicylic acid functionalized chitosan nanoparticle: A sustainable biostimulant for plant.

In this work, salicylic acid-chitosan nanoparticles (SA-CS NPs) are reported as a biostimulant for promoting plant defense and growth in maize. SA-CS NPs were characterised for colloidal size distribution, functional group, surface chemistry, chemical composition, crystal structure and morphology. Investigation discloses a method of SA-CS NPs synthesis, release profile of SA from SA-CS NPs, antifungal and seedling growth promoting activities. Findings unveil that SA-CS NPs expressed significant physiological-biochemical responses in vitro and in vivo. The responses were recorded as elevated antioxidant-defense enzyme activities, balancing reactive oxygen species (ROS), cell wall reinforcement by lignin deposition, disease control and plant growth in maize. In field, 59.4% control of post-flowering stalk rot (PFSR) disease and 57.8% yield enhancement was evident in SA-CS NPs application compared to SA treatment. The obtained results claim commercial potential of SA-CS NPs as a biostimulant for plant disease control and higher yield.

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.

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.

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.

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.