Characterization of the antifungal activity of iturin A against Fusarium oxysporum
2023
Emata, Y. | Kajikawa, A. | Yokota, K.
Iturin A is a cyclic lipopeptide, which consists of a heptapeptide with a betha-amino fatty acid, derived from Bacillus spp. Iturin A shows antifungal activity with a wide host range. It has been reported that iturin A forms membrane-pore in artificial lipid membrane. Due to the membrane-pore forming, iturin A treatment makes membrane damage and swell fungal cells Fluorescent staining assays, using fluorescein diacetate and propidiunm iodide, revealed the membrane-pore forming and cell death. Antifungal activity has been characterized to be divided to fungicidal and fungistatic activities. Fungicidal activity should be evaluated by spore germination and/or viable cell counting by plating methods. However, few paper described about fungicidal activity by such methods. In this study, authors therefore characterized the antifungal activity of iturin A against Fusarium oxysporum. To evaluate growth inhibition activity, authors conducted well diffusion method using half strength of potato dextrose agar plate. Purified iturin A was obtained from liquid culture of B. amylolifuefaciens ATCC21556 by organic solvent extraction followed by silica and ODS column chromatographies. Among the 5-tested strains of F. oxysporum, minimum inhibitory concentration were 50 to 100 mug/mL. To evaluate fungicidal activity, authors conducted spore germination assay. Microconidia suspension was obtained from culture plate of F. oxysporum. Purified iturin A was added to the microconidia suspension and incubated at 25 deg C for 2 hr followed by inoculation onto water agar plate. After 18 hr incubation at 25 deg C, spore germination was counted by microscopy. No inhibitions for spore germination were observed up to 200 mug/mL of purified iturin A. The data strongly suggested that iturin A has no fungicidal activities against F. oxysporum.
显示更多 [+] 显示较少 [-]