Antiviral and Antinematodal potentials of chitosan: Review

Chitosan: Properties and Its Application in Agriculture in Context of Molecular Weight

Chitosan is a naturally occurring compound that can be obtained from deacetylated chitin, which is obtained from various sources such as fungi, crustaceans, and insects. Commercially, chitosan is produced from crustaceans. Based on the range of its molecular weight, chitosan can be classified into three different types, namely, high molecular weight chitosan (HMWC, >700 kDa), medium molecular weight chitosan (MMWC, 150-700 kDa), and low molecular weight chitosan (LMWC, less than 150 kDa). Chitosan shows several properties that can be applied in horticultural crops, such as plant root growth enhancer, antimicrobial, antifungal, and antiviral activities. Nevertheless, these properties depend on its molecular weight (MW) and acetylation degree (DD). Therefore, this article seeks to extensively review the properties of chitosan applied in the agricultural sector, classifying them in relation to chitosan's MW, and its use as a material for sustainable agriculture.

Nematicidal Properties of Chitosan Nanoformulation

Chitosan is the second most abundant bio-polymer available in the world, second only to cellulose. It is found in crustaceous shells, e.g., those of crabs, shrimps, prawns, and fungi, as well as insect exoskeletons. The use of nanoformulations for the management of pests and diseases is receiving increased interest with the advancement of nanotechnology. Here, chitosan nanospheres were obtained from chitosan using the ionic gelation technique. The nanoformulations obtained were characterized using a particle size analyzer, Fourier transform infrared spectroscopy, and a transmission electron microscope. The efficacy of chitosan nanospheres in suppressing the root-knot nematode Meloidogyne incognita was studied. The particle size of nanospheres formulated for this study was 380.2 nm, with a polydispersity index (PI) of 0.4 and Zeta potential of 45.7 or 50.9 mV at pH 5.2. The chitosan nanospheres were spherical and the particles did not agglomerate. FTIR spectra of the chitosan nanospheres peaked at 3334 cm-1, thereby indicating the stretching of the OH and NH group. In In-vitro studies, chitosan nanospheres showed significant nematicidal activity against M. incognita. Under pot culture conditions, chitosan nanospheres (1%- active compound chitosan) at 2ml/plant decreased the nematode population in roots or soil. Compared to the control, the number of galls was reduced by 83.68%, the number of egg masses by 83.85%, the number of adult females by 66.56%, and the number of second-stage juveniles by 73.20%. In a field experiment, application of chitosan nanospheres (1%) was followed by a 18.75% increase in fruit yield compared to the non-treated control.