Morphological and molecular characterization of endophytic fungi isolated Alstonia boonei De Wild

Abstract

Endophytic fungi comprise a diverse group of fungal species that vary in symbiotic and ecological functions, and thought to contribute to the medicinal properties of certain host plants. The aim of this work was to investigate the biodiversity of endophytic fungi colonizing Alstonia boonei De Wild, a widely used medicinal plant in sub-Saharan Africa. Endophytic fungi were isolated from leaves, stem bark and root bark of A. boonei using potato dextrose agar (PDA), Sabouraud dextrose agar (SDA) and Czapek Dox agar (CZA) as recovery media, and malt extract agar (MEA) or yeast extract agar (YEA) for macroscopic characterization of isolates. Isolates were further characterized microscopically, and molecularly using conventional primers targeting the 5.8S ribosomal subunit. A total of 41 morphologically distinct isolate groups were obtained from 73 fungal isolates selected (28 in PDA, 26 in SDA and 19 in CZA), and microscopically classified into 9 genera (11 Fusarium spp, 03 Acremonium spp, 03 Trichoderma spp, 04 Neoscytalidium spp, 02 Xylaria spp, 03 Fomitiporia spp, 03 Phomopsis spp, 04 Lasiodiplodia spp, 02 Chaetomium spp and 06 non-sporulating isolates). Fifty-six (76.7 %) of the selected isolates were successfully amplified using fungal-specific primers, with PCR band sizes ranging from 500 to 665 base pairs. Of these, a total of 45 molecular variants were obtained, with Fusarium spp and Lasiodiplodia spp exhibiting the highest variability (14 and 12 molecular variants, respectively). Collectively, our data reveal strong colonization of A. boonei by phenotypically and genotypically diverse fungal endophytes, underscoring the critical importance of fungal symbiosis in A. boonei biology.