Application of Chitosan and Its Derivatives Against Plant Viruses

Abstract

Chitosan is a natural biopolymer that is industrially produced from chitin via deacetylation. Due to its unique properties and a plethora of biological activities, chitosan has found application in diverse areas from biomedicine to agriculture and the food sector. Chitosan is regarded as a biosafe, biodegradable, and biocompatible compound that was demonstrated to stimulate plant growth and to induce a general plant defense response, enhancing plant resistance to various pathogens, including bacteria, fungi, nematodes, and viruses. Here, we focus on chitosan application as an antiviral agent for plant protection. We review both the pioneer studies and recent research that report the effect of plant treatment with chitosan and its derivatives on viral infection. Special attention is paid to aspects that affect the biological activity of chitosan: polymer length and, correspondingly, its molecular weight; concentration; deacetylation degree and charge; application protocol; and experimental set-up. Thus, we compare the reported effects of various forms and derivatives of chitosan as well as chitosan-based nanomaterials, focusing on the putative mechanisms underlying chitosan-induced plant resistance to plant viruses.

Keywords: chitin; chitooligosaccharides; chitosan; chitosan nanoparticles; plant immunity; plant virus; systemic acquired resistance.

Figure 1

Chitosan activity against plant viruses depends on the plant–virus pair, CHT physico-chemical properties, and the experimental set-up.

Figure 2

Schematic representation of the putative mechanisms related to CHT-mediated plant resistance to viral infection. CW, cell wall; PM, plasma membrane; ROS, reactive oxygen species; RNAses, ribonucleases; SA, salicylic acid; JA, jasmonic acid; ABA, abscisic acid; RDRs, RNA-dependent RNA polymerases; SAR, systemic acquired resistance; PD, plasmodesmata.