Chitosan as Source for Pesticide Formulations

Abstract

Late blight and wilt caused by the oomycete, Phytophthora infestans, and the fungus, Fusarium solani f. sp. eumartii, respectively, are severe diseases in Solanaceae crops worldwide. Although traditional approaches to control plant diseases have mainly relied on toxic chemical compounds, current studies are focused to identify more sustainable options. Finding alternatives, a low molecular weight chitosan (LMWCh) obtained from biomass of Argentine Sea's crustaceans was assayed. In an attempt to characterize the action of LMWCh alone or in combination with the synthetic fungicide Mancozeb, the antimicrobial properties of LMWCh were assayed. In a side-by-side comparison with the SYTOX Green nucleic acid stain and the nitric oxide-specific probe, diaminofluorescein-FM diacetate (DAF-FM DA), yielded a similar tendency, revealing LMWChmediated cell death. The efficacy of LMWCh, Mancozeb, and the mixture LMWCh-Mancozeb was in turn tested. A synergistic effect in the reduction of F. eumartii spore germination was measured in the presence of subinhibitory dosis of 0.025 mg ml −1 LMWCh and 0.008 mg ml −1 Mancozeb. This mixture was efficient to increase the effectiveness of the single treatments in protecting against biotic stress judged by a drastic reduction of lesion area in P. infestans-inoculated tissues and activation of the potato defense responses.

Effect of chitosan for the control of potato diseases caused by Fusarium species

“…In fact, based on Qiu et al () findings, a coating with chitosan at 2.5 and 10.0 g/L is sufficient to limit the decay of green asparagus induced by Fusarium concentricum . Also, according to Ippólito et al (), the effectiveness of this antimicrobial compound against Phytophthora infestans and Fusarium eumartii , based on chitosan IC50 value (the concentration needed to inhibit half of the maximum spore germination), is estimated at 0.1 µg/ml and 130 µg/ml, respectively.…”

Transcriptome Analysis of Solanum Tuberosum Genotype RH89-039-16 in Response to Chitosan

“…Only recently, first transcriptome studies using an RNAseq approach have been reported in chitosan-treated strawberry (Landi et al, 2017) and avocado (Xoca-Orozco et al, 2017) fruits. While a protective effect of chitosan treatment on potato, e.g., against Phytophthora infestans (O'Herlihy et al, 2003;Chang and Kim, 2012;Ippoĺito et al, 2017) or potato virus X (Chirkov et al, 2001) has been described, no such transcriptomic study has been conducted in potato yet. However, several transcriptome analyses on potato have been published, e.g., describing gene expression under drought stress (Gong et al, 2015) and other abiotic and biotic stresses (Massa et al, 2013), mostly based on the reference data for the potato transcriptome by Massa et al (2011).…”

Toxicity Assessment and Control of Early Blight and Stem Rot of Solanum tuberosum L. by Mancozeb-Loaded Chitosan–Gum Acacia Nanocomposites

“…Chitosan has well documented antifungal activity, and in earlier research, low molecular weight chitosan alone or in combination with the commercial mancozeb controlled the spore formation for late blight and wilt caused by the pathogens P. infestans and Fusarium solani f. sp. eumartii , respectively [ 44 ]. Increasing the concentration of the nanofungicide provided better results, and was comparable to non-nanoform results.…”