In vitro antagonism between actinomycete isolates and Fusarium oxysporum f. sp. Ciceri: The causative agent of chickpea vascular wilt

Abstract

The chickpea is one of the most consumed crops in Algeria. Unfortunately, it is damaged by the phytopathogenic fungus Fusarium oxysporum f. sp. ciceri, the vascular wilt agent. In this study, we highlight the antagonistic activity of actinomycetes which we can use as biological tool to fight this dreaded phytopathogenic fungus. We recovered from the arid soils of southern Algeria, 61 isolates of actinomycetes with different morphological characteristics. Then, we tested the antagonistic activity of these actinomycete isolates, by various in vitro methods, on the growth of the phytopathogenic fungus. The thin layer chromatography was used on the selected actinomycete extract. As results, we obtained 06 isolates of actinomycetes (ACT1, ACT2, ACT3, ACT4, ACT5 and ACT6) presenting potential antagonistic activities against 3 isolates of F. oxysporum f. sp. ciceri (FOC8, FOC13 and FOC15). Preliminary identification using morphological criteria revealed the presence of Streptomyces characteristics for the 6 isolates. The activity of the crude extract from the selected actinomycete isolates against the 3 isolates of F. oxysporum f. sp. ciceri showed that the activity of the isolate ACT2 was greater compared to the others. The thin layer chromatography of the culture filtrate crude extract showed the presence of 5 fractionswith each fraction representing bioactive molecules.