Endophytic fungi from the medicinal plant Aloe dhufarensis Lavranos exhibit antagonistic potential against phytopathogenic fungi

Aloe dhufarensis Lavranos is an important medicinal plant, however, the endophytic microorganisms associated with this plant and their antagonistic activities are not known. In this study, endophytic fungi and bacteria were isolated from the leaf tissues of A. dhufarensis and their antagonistic activity against the plant pathogens Fusarium sp. and Cladosporium sp. were evaluated using a dual culture assay. A total of 3 fungal endophytes and 12 bacterial endophytes were isolated from the leaf tissue segments of A. dhufarensis. Among them, two endophytic fungal isolates designated as SQUCC-F2-2 and SQUCC-F3-1 exhibited inhibitory activity against the phytopathogenic fungi tested. In addition, scanning electron microscopy analysis showed that they induced shriveling, pit formation and disintegration of the hyphae of the phytopathogenic fungi. These two endophytic fungal isolates were identified as Sarocladium kiliense (SQUCC-F2-2) and Penicillium oxalicum (SQUCC-F3-1) on the basis of nuclear ribosomal DNA internal transcribed spacer (ITS) region. Analysis of the metabolites produced by these endophytes revealed the presence of fatty acids, fatty acid methyl esters, furfuryl alcohol, 1,2-diols and amide, which have been identified in the literature as antimicrobial compounds. P. oxalicum produced 7 compounds, of which 2-Furanmethanol, Dodecanoic acid and Tetradecanoic acid were dominant. S. kiliense produced 8 compounds with 2,3-Butanediol as the main constituent. This is the first report of endophytic fungi of A. dhufarensis with antagonistic activity against phytopathogenic fungi.