Antifungal activity of chitosan against Fusarium oxysporum f. sp. cubense

Abstract

The in vitro antifungal activity of chitosan against Fusarium oxysporum f. sp. cubense Race 4 (FocR4) the causal agent of banana wilt was investigated. Chitosan at all concentrations tested reduced the hyphal growth of FocR4 on potato dextrose agar media and recording maximum inhibition of 76.36% at 8 mg/mL. The inhibitory effect was found to increase as chitosan concentration increases. The 50% effective concentration value was estimated by probit analysis, and it was 1.4 mg/mL. Chitosan was more effective in potato dextrose broth where it completely inhibited the mycelial growth of FocR4 at all concentrations tested. Chitosan inhibited the sporulation of FocR4 by a maximum of 96.53% at 8 mg/mL chitosan, and 100% inhibition for spore germination was recorded at all concentrations tested. Chitosan at concentrations of more than 1.6 mg/mL was also found to induce morphological changes in FocR4 characterized by agglomeration of hyphae, abnormal shapes, vesicles, or empty cells devoid of cytoplasm in the mycelia.

Study on Antifungal Ability of Water Soluble Chitosan Against Green Mould Infection in Harvested Oranges

“…The similar results were also recorded in other fungi such as Fusarium oxysporum f. sp. cubense (Al-Hetar et al, 2010), Alternaria kikuchiana Tanaka, Physalospora piricola (Meng et al, 2010), Collectotrichum sp. (Ali, Muhammad, Sijam, & Siddiqui, 2010;Jitareerat et al, 2007;Muñoz, Moret, & Garcés, 2009).…”

“…First, WSC possesses mainly amino groups in its structure (Kim & Rajapakse, 2005). So, because of its polycationic nature, it interferes with negatively charged residues of fungal cell wall surface (Al-Hetar et al, 2010). This interaction can alter permeability characteristics of fungal cell membrane and further prevent the entry of materials or lead to the leakage of intracellular electrolytes and proteinaceous constituents that finally causes the death of fungi (Kim & Rajapakse, 2005).…”

“…Inhibitory effect of mycelial growth was determined by measuring colony diameter until colony of control sample reached the edge of the plate. The percentage inhibition of radial growth was calculated according to Al-Hetar, Zainal Abidin, Sariah, and Wong (2010).…”

“…The mycelium were filtered, dried at 100 o C for 24 hours and weighed. The inhibition effect of WSC based on dried biomass was estimated according to Al-Hetar et al (2010). Each experiment was carried out in five replicates.…”

Chitosan and ß-amino butyric acid up-regulates transcripts of resistance gene analog RGPM213 in pearl millet to infection by downy mildew pathogen

“…This compound has shown properties, such as bioactivity and biocompatibility [30]. The research out come from the literature have shown that, when used in plants, chitosan can increase the yield [31], reduce transpiration [32] and induce a range of metabolic changes as a result of which, plants become more resistant to viral, bacterial and fungal infections [33]. In addition, plants treated with chitosan may be less prone to stress stimulated by unfavourable conditions, such as drought, salinity, low or high temperature [34 and 35].…”