Exploitation of functionalized green nanomaterials for plant disease management.

A crucial determining factor in agricultural productivity is biotic stress. In addition, supply of quality food to the ever-increasing world's population has raised the food demand tremendously. Therefore, enhanced agricultural crop productivity is the only option to mitigate these concerns. It ultimately demanded the often and indiscriminate use of synthetic agrochemicals such as chemical fertilizers, pesticides, insecticides, herbicides, etc. for the management of various biotic stresses including a variety of plant pathogens. However, the food chain and biosphere are severely impacted due to the use of such harmful agrochemicals and their byproducts. Hence, it is need of hour to search for novel, effective and ecofriendly approaches for the management of biotic stresses in crop plants. Particularly, in plant disease management, efforts are being made to take advantage of newly emerged science i.e. nanotechnology for the creation of inorganic nanoparticles (NPs) such as metallic, oxide, sulphide, etc. through different routes and their application in plant disease management. Among these, green nanomaterials which are synthesized using environmentally friendly methods and materials reported to possess unique properties (such as high surface area, adjustable size and shape, and specific functionalities) making them ideal candidates for targeted disease control. Nanotechnology can stop crop losses by managing specific diseases from soil, plants, and hydroponic systems. This review mainly focuses on the application of biologically produced green NPs in the treatment of plant diseases caused due to bacteria, viruses, and fungi. The utilization of green synthesis of NPs in the creation of intelligent targeted pesticide and biomolecule control delivery systems, for disease management is considered environmentally friendly due to its pursuit of less hazardous, sustainable, and environmentally friendly methods.

Chitosan nanoparticles (ChNPs): A versatile growth promoter in modern agricultural production.

Agriculture is a backbone of global economy and most of the population relies on this sector for their livelihood. Chitosan as a biodegradable material thus can be explored for in various fields in its nano form to replace non-biodegradable and toxic compounds. The chitosan has appealing properties like biocompatibility, non-toxicity, biodegradability, and low allergenic, making it useful in several applications including in agriculture sector. Because of their unique properties, chitosan nanoparticles (ChNPs) are extensively applied as a bioagent in various biological and biomedical processes, including wastewater treatment, plant growth promoter, fungicidal agent, wound healing, and scaffold for tissue engineering. Furthermore, the biocompatibility of chitosan nanoparticles (ChNPs) is reported to have other biological properties such as anti-cancerous, antifungal, antioxidant activities, even induces an immune response in the plant, and helps manage biotic and abiotic stresses. Chitosan can also find its application in wastewater treatment, hydrating agents in cosmetics, the food industry, paper, and the textile industry as adhesive, drug-delivering agent in medical as well as for bioimaging. Since chitosan has low toxicity, the nano-formulation of chitosan can be used for the controlled release of fertilizers, pesticides, and plant growth promoters in agriculture fields. The ChNPs applications in precision farming being a novel approach in recent developments. Here we have comprehensively reviewed the major points in this review are; the synthesis of ChNPs by biological resources, their modification and formulation for increasing its applicability, their modified types, and the different agricultural applications of ChNPs.

Gamma radiation degradation of chitosan for application in growth promotion and induction of stress tolerance in potato (Solanum tuberosum L.).

Oligo-chitosan (82.20 kDa) was prepared from chitosan (337.73 kDa) by application of 100 kGy γ-irradiation. UV-vis spectroscopy, FTIR, XRD, DSC and TGA analyses showed typical properties of chitosan with slight variations after γ-irradiation. Degree of deacetylation of chitosan and oligo-chitosan was 82%, while 1,1-diphenyl-2-picrylhydrzyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging activity were 10.01 ± 0.18 and 43.30 ± 3.75 µMTE/mL and 13.64 ± 0.16 and 79.93 ± 4.44 µMTE/mL, respectively. Chitosan and oligo-chitosan was applied as foliar spray on potato plants to analyze growth promoting and stress tolerance inducing effects. Improvement in shoot height and number of nodes was observed after foliar spray of chitosan and oligo-chitosan at 50-75 mg/L. Furthermore, membrane stability index and malondialdehyde reduced while chlorophyll, carotenoids, proline, reducing and total sugars, enhanced considerably. The antioxidant and defense enzymes CAT, POD, SOD, chitinase and chitosanase showed prominent increment. Overall results indicated that chitosan (75 mg/L) and oligo-chitosan (50 mg/L) can augment plant growth and induce defense mechanism for drought stress tolerance in potato.