How promising are endophytic fungi as alternative sources of plant secondary metabolites?

Endophytic fungi, which colonize plants internally without apparent adverse effects, occur ubiquitously in plants'. In contrast to their pathogenic fungal counterparts, the endophytic fungi exist in a mutualis�tic association with their host plants, and in few cases, enhance the ability of plants to tolerate abiotic2 and biotic3 stresses. In culture, outside of their host tissue, endophytic fungi are also known to produce a number of important secon-dary metabolites including anti-cancer, anti-fungal, anti-diabetic and immuno-suppressant compounds'/1. Occasionally, these compounds are the same as those produced by the respective host plants, thus triggering the expectation that endophytic fungi can serve as an alterna�tive source of important plant secondary metabolites. This possibility was perhaps first realized and mooted by Stierle and his co-workers, following their discovery that the endophytic fungus Taxomyces andreanae of the yew plant Taxus brevi�folia could also produce taxol (generic name: paclitaxel), the multi-billion dollar anti-cancer compound produced by the yew plants.