Pyrenochaeta sp. DS3sAY3a v1.0
Light microscope image showing hyphae of Pyrenochaeta sp. DS3sAY3a.  Dark brown particle attached to hyphae is an aggregate of Mn-oxide minerals produced by the fungus.  Field of view is 0.95 mm.
Light microscope image showing hyphae of Pyrenochaeta sp. DS3sAY3a. Dark brown particle attached to hyphae is an aggregate of Mn-oxide minerals produced by the fungus. Field of view is 0.95 mm.
Photo by Cara Santelli

Pyrenochaeta species belong to a group of filamentous Ascomycete fungi that inhabit soil and plant debris worldwide, and are well-known known as pathogens for a variety of plants and, occasionally, humans. In humans, Pyrenoachaeta romeroi has been associated with mycetoma and P. unguis-hominis infects nails.  Several species of fungi infect plants, particularly plant roots, leading to major losses of crops such as tomatoes and cucurbits (P. lyopersici), and onions (P. terrestris).  These pathogenic species secrete small molecules and enzymes (e.g., cellulase and polygalacturonase) that promote cell wall degradation of the plant roots, ultimately leading to plant disease and growth inhibition.  Species-level determinations of Pyrenochaeta sp. DS3sAY3a have not yet proven successful due to inconclusive results of 18S and 28S rRNA genes and Internal Transcribed Spacer (ITS) region phylogenetic analysis. Currently, however, Pyrenochaeta sp. DS3sAY3a is being investigated for its role in the remediation of metal polluted environments due to the oxidation of manganese (Mn) compounds.  Additionally, Mn(III) compounds,  Mn(III/IV) oxide minerals (highly reactive oxidants), and other reactive metabolites produced by Pyrenochaeta sp. DS3sAY3a promote carbon degradation as well as the biogeochemical cycling of other metals in the environment. Production of reactive metabolites and oxidants by Pyrenochaeta sp. DS3sAY3a  and other Pyrenochaeta species is linked in part to secreted proteins, cell differentiation, nutrient composition, and species interactions, although the molecular mechanisms are not fully resolved. Genome sequencing in concert with transcriptome and secretome analysis of this and related Ascomycete fungi that promote lignocellulose degradation and Mn(II) oxidation will improving our understanding of the growth-specific production and total production potential of reactive metabolites and oxidants by Pyrenochaeta sp. DS3sAY3a.  Ultimately, these results will improve model predictions of carbon degradation and CO2 emissions in a changing biogeochemical landscape as well as provide plausible approaches to increase carbon sequestration, metal bioremediation, and pathogen resistance. 

Genome Reference(s)