Antifungal potential of Corallococcus sp. strain EGB against plant pathogenic fungi

Antifungal microorganisms have play an important role in the biological control of plant fungal pathogens. In this study, strain EGB, which was identified as a Corallococcus sp. with excellent antifungal activity, was selected as a biocontrol agent against phytopathogenic fungi from 41 myxobacterial isolates in previous research. Efficient biocontrol activity of Corallococcus sp. EGB was observed on plate assays and pot experiments. Corallococcus sp. strain EGB exhibited efficient biological control of Fusarium oxysporum, significantly decreasing the incidence of Fusarium wilt to 7.7% and the disease severity from 61.2% to 7.5%. Microscopic observations of hyphae as well as periodate oxidation analysis and HPLC analysis of the oligosaccharides released from yeast cell wall treated with crude enzymes preparation from Corallococcus sp. strain EGB revealed that a β-1,6-glucanase might be involved in the antifungal mechanism. Such results differ from previews reports primarily attributing the antifungal activity of myxobacteria to secondary metabolites. Our study highlights Corallococcus sp. strain EGB as a novel type of biocontrol agent, which may have potential application in the control of plant pathogenic fungi.