Bioactivity of Fungal Endophytes as a Function of Endophyte Taxonomy and the Taxonomy and Distribution of Their Host Plants

Abstract

Fungal endophytes – fungi that grow within plant tissues without causing immediate signs of disease – are abundant and diverse producers of bioactive secondary metabolites. Endophytes associated with leaves of tropical plants are an especially exciting and relatively untapped source of novel compounds. However, one major challenge in drug discovery lies in developing strategies to efficiently recover highly bioactive strains. As part of a 15-year drug discovery project, foliar endophytes were isolated from 3198 plant samples (51 orders, 105 families and at least 232 genera of angiosperms and ferns) collected in nine geographically distinct regions of Panama. Extracts from culture supernatants of >2700 isolates were tested for bioactivity (in vitro percent inhibition of growth, % IG) against a human breast cancer cell line (MCF-7) and the causative agents of malaria, leishmaniasis, and Chagas' disease. Overall, 32.7% of endophyte isolates were highly active in at least one bioassay, including representatives of diverse fungal lineages, host lineages, and collection sites. Up to 17% of isolates tested per assay were highly active. Most bioactive strains were active in only one assay. Fungal lineages differed in the incidence and degree of bioactivity, as did fungi from particular plant taxa, and greater bioactivity was observed in endophytes isolated from plants in cloud forests vs. lowland forests. Our results suggest that using host taxonomy and forest type to tailor plant collections, and selecting endophytes from specific orders or families for cultivation, will markedly increase the efficiency and efficacy of discovering bioactive metabolites for particular pharmaceutical targets.

Phylogenomics and evolution of secondary metabolism in plant-associated fungi

“…Lophodermium) and colonize a broad phylogenetic diversity of plant species [7]. They are a rich and relatively unsampled source of novel bioactive compounds [16,17 ], with genomic sequencing of some species (e.g. Pestalotiopsis [18]) documenting some of the highest potential of secondary metabolism among fungi.…”

Detecção de compostos voláteis com atividade antibacteriana por fungos endofíticos associados à Costus spiralis

“…Apesar dos fungos serem reconhecidos como uma importante fonte de produtos bioativos naturais é estimada que, uma grande quantidade destes compostos, se encontre ainda por identificar [5]. Desta forma, estudos que visem à avaliação da diversidade fúngica em diversos ecossistemas e a bioprospeção de novos produtos naturais resultantes do seu metabolismo, contribuirão para a obtenção de novos fármacos.…”

Assessment of endophytic yeast diversity in rice leaves by a culture-independent approach

“…Endophytes have been receiving attention due to their ability to produce various beneficial bioactive compounds which are involved in plant health and adaptation to both abiotic and biotic stress and thus have potential agricultural, industrial and pharmaceutical applications (Trindade et al 2002;Arnold et al 2003;Tian et al 2004;Higginbotham et al 2013). At present it is commonly accepted that almost every plant species is inhabited by endophytic fungi and that more than one type of fungal endophyte may be found within a single plant (Petrini et al 1992).…”