Chitosan-Based Agronanochemicals as a Sustainable Alternative in Crop Protection

Abstract

The rise in the World’s food demand in line with the increase of the global population has resulted in calls for more research on the production of sustainable food and sustainable agriculture. A natural biopolymer, chitosan, coupled with nanotechnology could offer a sustainable alternative to the use of conventional agrochemicals towards a safer agriculture industry. Here, we review the potential of chitosan-based agronanochemicals as a sustainable alternative in crop protection against pests, diseases as well as plant growth promoters. Such effort offers better alternatives: (1) the existing agricultural active ingredients can be encapsulated into chitosan nanocarriers for the formation of potent biocides against plant pathogens and pests; (2) the controlled release properties and high bioavailability of the nanoformulations help in minimizing the wastage and leaching of the agrochemicals’ active ingredients; (3) the small size, in the nanometer regime, enhances the penetration on the plant cell wall and cuticle, which in turn increases the argochemical uptake; (4) the encapsulation of agrochemicals in chitosan nanocarriers shields the toxic effect of the free agrochemicals on the plant, cells and DNA, thus, minimizing the negative impacts of agrochemical active ingredients on human health and environmental wellness. In addition, this article also briefly reviews the mechanism of action of chitosan against pathogens and the elicitations of plant immunity and defense response activities of chitosan-treated plants.

Boosting photosynthetic machinery and defense priming with chitosan application on tomato plants infected with Fusarium oxysporum f. sp. lycopersici

“…actinidiae pathosystem, the application of chitosan induced 3.5 times the expression of the PR1 gene when compared to the control (Corsi et al, 2017). The gene expression results indicate that chitosan presumably induces the plant to strengthen its immune system against pathogens, highlighting the potential of chitosan as a preventive, biocompatible, and non-toxic strategy for disease management (Dubin et al, 2020;Maluin and Hussein, 2020;Chowdhury et al, 2017).…”

Chitosan Hydrochloride Decreases Fusarium graminearum Growth and Virulence and Boosts Growth, Development and Systemic Acquired Resistance in Two Durum Wheat Genotypes

“…In this regard, chitosan was extensively evaluated as a plant biostimulant and antimicrobial agents against different plant pathogens (fungi, bacteria, and viruses), and recently against different Fusarium spp. [ 51 , 52 , 53 , 54 ], and the modes of action have been hypothesized to describe its ability to boost plant growth and defense mechanism [ 39 , 50 ]. Many studies evaluated the antifungal ability of chitosan against FHB pathogens in vitro and in vivo.…”

“…Regarding the antimicrobial mechanism of chitosan, several researchers have presented their hypotheses on the direct and/or indirect effects against pathogens: The positive charge of the protonated chitosan enables electrostatic interaction with the negative charge of the pathogens surface; chitosan increases the permeability of the membrane by damaging the cells of the pathogens resulting in cell death [ 58 ]; chitosan is also able to chelate the essential elements for the growth of the pathogens, such as metal ions, minerals, and nutrients, preventing the normal growth of the pathogens; chitosan may also interact with DNA or RNA leading to the inhibition of the mRNA synthesis; the deposition of chitosan on plant and pathogen surface forms a biofilm that limits the nutrient availability for microorganisms [ 59 , 60 , 61 ]; the ability of chitosan to induce the SAR in plants is associated with its elicitor-like properties, which boost the early activation of pathogenesis-related proteins and improve the plant resistance. As a result, chitinase and β-1,3-glucanase (PR2) enzymes degrade the fungal cell wall and stop its growth on the host plant [ 39 , 50 , 61 ].…”

“…This body of research suggests that chitosan can be used as biostimulant of the plant immune system to challenge diverse hostile environments. In addition, many research studies stated that pathogenesis-related (PR) genes and several defense-related enzymes such as phenylalanine ammonia-lyase (PAL) are induced by chitosan [ 39 , 48 , 49 , 50 ].…”

A Mini-Review on Chitosan-Based Hydrogels with Potential for Sustainable Agricultural Applications

“…CS nanoformulations for agrochemicals delivery has received much attention recently [ 29 , 30 , 31 , 32 ]. CS-based agronanochemicals represent a sustainable alternative to conventional agrochemicals in crop disease management.…”