An Endophytic Fungus from Cephalotaxus: Phoma SP. which Produces Anti-Fungal Substances

Extract

Various species of endophytic fungi produce a variety of potentially useful new Pharmaceuticals in host tissue of different plants. As an example, the anti-cancer drug, taxol is produced by several species of fungi isolated from various host species.

A Phoma was isolated from the inner bark of Cephalotaxus fortunei growing near Hangzhou, China. After 7-10 days of incubation at 23C cultures were hyphal tipped and transferred to PDA and gamma-irradiated carnation leaves. Cultures which produced bioactive substances were studied further. This Phoma sp. is particularly active against Pythium ultimum. Another endophytic Phoma sp. isolated from Taxus wallachiana also makes antimetabolite compounds. Presumably these endophytic Phoma spp. exist in a symbiotic relationship with various tree species contributing substances that inhibit or destroy invading pathogenic fungi and bacteria.

The fungus produces globose dark brown, thin-walled pycnidia which are semi-immersed in carnation leaf pieces (Fig. 1). Cream-colored conidia (Fig. 2), which average 4.5-5 × 1.75-3 μm are produced in pycnidia with a single ostiole normally obscured by a gelatinous mass (Fig. 3), which is characteristically not evident on old pycnidia (Fig. 4). Conidia are formed enteroblastically from discrete phialidic conidiogonous cells attached directly to the pycnidial wall. Sclerotia (ca. 1.5-2 mm) are also produced on PDA.