Isolation and morphological characterization of endophytic fungi isolated from mangrove plants along the Kenyan coastline

Microorganisms in marine ecosystems are exposed to harsh conditions, thus such systems are of interest in bioprospecting for useful secondary metabolites. The aim of the study was to isolate and identify the fungal endophytes that colonize mangroves. The fungal endophytes were isolated from the leaves, roots, and branches of different mangrove plants (Bruguiera gymnorrhiza, Heritiera littoralis, Xylocarpus granatum, Rhizophora mucronata, and Avicennia marina) from Mida creek, Tudor creek and Gazi bay using Point-Centered Quarter Sampling method and then, morphologically characterized. A total of 76 fungal isolates were obtained and identified using macro- and micro-morphological features. The isolates were affiliated with eight different genera (Aspergillus, Cladosporium, Nigrospora, Fusarium, Alternaria, Lasiodiplodia, Chaetomium and Penicillum).  Aspergillus spp. were the most prominent with a colonization frequency of 38.9 and 55.6% in root and branch tissues, respectively while Chaetomium species were the least frequent appearing only in one branch tissue. Mida creek had the highest total number of endophytic isolates (52.6%) followed by Gazi bay (27.6%). Majority (30.3%) of the endophytic fungal isolates were obtained from Avicennia marina. The results indicate that mangrove species are a source of diverse endophytic fungi that may have useful biotechnological applications.   Key words: Mangrove species, endophytic fungi, fungi diversity, colonization frequency.