In vitro efficacy of biologically active compounds derived from Navicula arenaria against soil borne phytopathogenic Macrophomina phaseolina and Fusarium oxysporum

Asmaa Alallaf,Metwally Kotab,Ahmed Elsayed,Hesham Shafik

doi:10.21608/ajbas.2021.67687.1048

Abstract

Navicula arenaria Donkin 1861 is a marine microalga belongs to class of bacillariophycea. Recently, microalgae and their products are used as biological control of diseases caused by phytopathogenic fungi. This is considered environmentally ecofriendly method to overcome the plant damage caused by soil borne pathogenic fungi and thereby economic loss. Therefore, this study aimed to investigate in vitro the antifungal activity of N. arenaria isolate PS 31 extracellular and intracellular metabolites against two taxa of soil borne phytopathogenic fungi; Macrophomina phaseolina and Fusarium oxysporum. N. arenaria PS 31 hexane extract was the most effective extract on growth inhibition of both phytopathogenic fungi. There is no significant difference between miconazole and N. arenaria hexane extract of 5.6 mg/ml on growth inhibition of F. oxysporum. The inhibitory effect of hexane extract at 5.6, 4.2 and 2.8 mg/ml and ethyl acetate extract at 35% (v/v) was higher than controls. Ethyl acetate extract was effective on growth inhibition of M. phaseolina (29.67%). GC-MS analysis of N. arenaria hexane fraction revealed the presence of potent antifungal compounds such as Phenol, 2,2'-methylenebis[6-(1,1-dimethylethyl)-4-methyl-, di-n-octyl phthalate, cholestane-3,5-diol, 5-acetate,(3.beta.,5.alpha.), Cholestan-3-ol,(3.beta.,5.beta.)- and beta.-Sitosterol. These results suggest that N. arenaria hexane extract can be used in biological control of plant diseases caused by M. phaseolina and F. oxysporum.

Highlights

Diatoms are unicellular microalgae with silica shields and belong to class of bacillariophycae
The plant damage caused by soil borne pathogenic fungi has led to the focusing of considerable effort for fighting plant pathogens using natural products extracts as safe alternatives to synthetic fungicide [3]
The aim of this research is to evaluate the antifungal activity of N. arenaria metabolites against Fusarium oxysporum and Macrophomina phaseolina that are considered two sorts of soil borne pathogenic fungi

Summary

Introduction

Diatoms are unicellular microalgae with silica shields and belong to class of bacillariophycae. The plant damage caused by soil borne pathogenic fungi has led to the focusing of considerable effort for fighting plant pathogens using natural products extracts as safe alternatives to synthetic fungicide [3]. Conventional strategies that involves the utilization of chemical fungicides are used in the control of soil borne phytopathogenic fungi. The application of synthetic fungicides can cause harmful problems to the environment and other organisms [4]. There is an increased attention toward the utilization of algae as a biocontrol agent for plant disease management to reduce the use of fungicides and this considered ecofriendly method to environment for protecting crops from soil borne pathogenic fungi [5,6]

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Results