Biocontrol Potential of Rhizospheric Fungi from Moringa Oleifera, their Phytochemicals and Secondary Metabolite Assessment Against Spoilage Fungi of Sweet Orange (Citrus Sinensis)

This investigative study aimed to assess the antifungal potential of Trichoderma viride and Penicillium chrysogenum isolated from Moringa oleifera rhizosphere against spoilage fungi of Citrus sinensis, as well as evaluate their phytochemical profile.？ The bio-agents (T. viride and P. chrysogenum) and the Citrus sinensis spoilage fungi were isolated following standard microbiological protocols. Initial in-vitro screening of the isolated bio-agents against the citrus pathogens in the confrontational assay was done. Phytochemical screening and antifungal activity of metabolites produced by the bioagents against the pathogens were also investigated. The inhibitory concentration (minimum/maximum: MIC and MFC) of the bioagent metabolites on the citrus pathogens was also assessed. The isolation screening investigation indicated that citrus pathogens isolated were P. digitatum, A. wenti, C. tropicalis and F. oxysporum and that P. digitatum had the highest frequency (43 %) of occurrence. The results also revealed that T. viride and P. chrysogenum significantly inhibited the pathogens on petri-plates using dual-confrontational assay. The phytochemical profile of the bioagents indicated there were flavonoids, cardiac glycosides, phenols, alkaloids, tannins, saponins and steroids present. Metabolites of the bioagents against the pathogens indicated that T. viride recorded the highest MIC against Fusarium oxysporum77±1.0and the highest MFC against Aspergillus wentti 97±1.0. Also, P. chrysogenum recorded the highest MIC against Fusarium oxysporum 59±1.0 and the highest MFC against Fusarium oxysporum74.33±1.52. This study indicated the antagonistic potentials of using Trichoderma viride and Penicillium chrysogenum in controlling pathogens of citrus sinensis and this could be exploited further in formulating biopesticides to improve post-harvest qualities of Citrus