Studies on Tricellulortus pepoformis, a tropical mitosporic fungus
Peláez, F.; Collado, J.; Platas, G.; Diez, T.; Basilio, A.; González, A.; Vicente, F.; Dai, P.; Harris, G.; Rosenbach, M.; Dreikorn, S.; Thompson, J.
Tricellulortus pepojormis is an uncommon tropical mitosporic fungus, which was first described by Matsushima (1995) from leaf litter collected in Japan. The fungus is characterized by conidia of striking pumpkin-like morphology, bearing three (rarely four) conical protuberances produced from three adjacent conidiogenous cells. However, nothing is known about its phylogenetic affinities. Recently, while surveying tropical leaf-litter fungi as potential producers of bioactive natural products, we isolated this fungus from leaf litter collected in Barbados. The isolate produced antifungal activity against Candida albicans, C. tropicalis, Aspergillus fumigatus and Cryptococcus neojormans, and a weak antibacterial activity against Bacillus subtilis. This activity seems to be due to an unstable polyacetylene, as inferred from the UV spectrum of the active fractions recovered after separation of the fungal extract by countercurrent chromatography. Polyacetylenes are widespread compounds throughout the basidiomycetes. Genomic DNA was extracted from the isolate, and the D1-D2 region of the 28S rRNA gene, as well as the ITS 1-5.8S-ITS2 region, were sequenced. Although a comparison of these sequences with the GenBank database failed to find any sequence with sufficiently high similarity to classify this fungus at the species or even genus level, it unequivocally suggested that the sequence is that of a basidiomycete. The closest sequences found were those of Multiclavula corynoides and Multiclavula vernalis, which showed about 93% similarity in the D1 - D2 region.