Mechanism of Action of Effective Microbes Against Fusarium oxysporum f. sp. melonis in vitro

Résumé fourni par la source

The use of effective microbes obtained from the rhizosphere to suppress soil borne plant pathogens has received greater attention in recent decades as an alternative to chemical fungicides. The present study was conducted to explore the effects of effective microbes (EMs) and to understand the mechanisms of action and their ability to produce inhibitory metabolites and hydrolytic enzymes that enhance their antagonistic capability and activity against Fusarium wilt caused by Fusarium oxysporum f. sp. melonis (Fom), as well as plant growth promotion activity on the rock melon plant. Seven EMs namely Bacillus amyloliquefaciens MKB04 (KM220772). MKB09, Alcaligenes faecalis MKB10 (KM220771), MKB12, MKB15, MKB24 and MKB37 were selected, The in vitro evaluation of antifungal compound production was found to be a common characteristic among the seven selected potential bacterial isolates. Moreover, the isolates showed strong antagonistic activity and different mechanisms of action in the diffusible metabolites assay compared to the volatile one, This characteristic significantly add to its role in controlling Fom, where the bacterial isolates exhibited significantly different combinations of antimicrobial metabolites, such as cellulase, pectinase, proteases and chitinases. The activities of the various effective bacteria isolates were shown by the clear zones that formed surrounding the colonies of bacteria. Furthermore, the isolates responded positively in vitro for siderophore and HCN, indole acetic acid (IAA) production, and phosphate solubilisation. As effective microbes are environmental friendly and in vitro antagonistic and hydrolytic activities it showed against F.oxysporium f. s. melonis in this study suggest that they can be used as an effective biological control agent as well as plant growth promoters.