New sordarialean lineage Garciamycella chlamydospora (Sordariales, Schizotheciaceae) produces rare antifungal papulacandins

Abstract

The new genus Garciamycella is here erected to accommodate the soil-borne fungus G. chlamydospora, as well as G. cyclaminis and G. fici, based on a phylogenetic study using sequences of ITS, LSU, rpb2, and tub2. The establishment of Garciamycella has important taxonomic implications, as it helps to resolve a phylogenetically distinct lineage in the order Sordariales, a group in which the placement of numerous taxa remains uncertain. The new species G. chlamydospora was investigated for its secondary metabolite production, affording one previously undescribed papulacandin derivative (1), together with two known compounds from the same family, Mer-WF3010 (2) and papulacandin D (3). In addition, two previously undescribed metabolites, penazaphilone M (4) and cremenoic acid (5), were isolated alongside the known derivatives cremenolide (6) and aspinolide B (7). All compounds were isolated using preparative high-performance liquid chromatography (HPLC), and their chemical structures were elucidated through comprehensive 1D and 2D NMR spectroscopic analyses, in addition to high-resolution mass spectrometry (HR-MS). Antimicrobial and cytotoxic activities were assessed for all metabolites, and compounds (1-3) revealed potent antifungal activity. This research highlights how exploring novel fungal taxa can lead to the discovery of structurally unique metabolites with significant antifungal properties. It further confirms the potential of the order Sordariales as prolific producers of bioactive compounds with potential applications in the development of new antifungal agents.