Antimicrobial Activities of Endophytic Fungal Crude Extracts Isolated from Cashew Tree (Anacardium occidentale)

Abstract

This study presents the antimicrobial activities of endophytic fungal crude extracts isolated from leaves, stems and roots of cashew trees (Anacardium occidentale) which showed disease symptoms and those resistant from Fusarium wilt in Mtwara region. Sections of the cashew trees were made and cultured to isolate endophytes. Eight endophytes were isolated and characterized by using morphological and molecular markers. Neopestalotiopsis, Penicillium, Lasidioplodia and Daldinia sp isolated from resistant tree and Auxarthron and Aspergillus sp from diseased tree. Antimicrobial activities of the isolated endophytic fungal crude extracts were done against pathogenic Fusarium oxysporum and three human pathogens namely, Staphylococcus aureus, Escherichia coli, and Candida tropicalis. Results showed that all endophytic fungal crude extracts isolated from resistant plants and one from diseased plants exhibited positive antimicrobial activities against bacteria and fungus Candida tropicalis but they had no antifungal activity against Fusarium oxysporum.  This study could contribute to the discovery and innovation of therapeutics. This study also implied that the resistance against Fusarium wilt disease might be caused by other unknown factors. More research work is recommended for establishing other possible factors including endophytic bacteria, biotic and abiotic factors that could contribute to resistance of cashew plants to Fusarium oxysporum.

Keywords: Antifungal; Phytopathology; Endophyte; Cashew nut disease