Fungal biodiversity and natural products discovery: perspectives and prospects

Fungi are well known as prolific sources of unique and diverse bioactive natural products. Many members of commonly occurring fungal genera have been extensively surveyed, and new metabolites continue to be found among these metabolically talented fungi, but species investigated to date appear to represent only a small fraction of estimated fungal biodiversity. As genomic data emerge on an ever-broadening cross-section of fungal species, it is evident that many underexplored groups possess relatively untapped secondary metabolic capabilities. Some fungal metabolite classes occur among disparate taxa, while others have been found only within a narrow taxonomic range, suggesting that underexplored groups offer attractive prospects for new natural product discoveries.

Rapid technological advances and developments in genome-based predictive capabilities will continue to improve the ability to detect and access new fungal metabolites, but even with the power of these emerging methodologies, prioritization strategies are important in providing direction. Mycological insights can be helpful in this regard, as metabolic or bioactivity themes may emerge along ecological or taxonomic lines. Our efforts to seek new bioactive metabolites have focused on fungi from under-sampled communities targeted on the basis of several criteria, including hypotheses about roles of chemistry in antagonistic or defensive interactions, as well as the presence of distinctive taxa. Such strategies are constrained by the need for taxonomic characterization of isolates at some level, and strain selection is only one of many variables that affect the productivity of fungal cultures. Studies of unusual species or isolates from under-sampled habitats are not always fruitful, but positive results can help identify clades or ecological groups that warrant future focus. This presentation is intended to offer perspectives gleaned from this type of approach as they relate to the potential of some representative underexplored veins of fungal diversity.

Keywords: Fungi, Biodiversity, Taxonomy, Natural Products.