RESUMEN
Rock-inhabiting fungi (RIF) are usually extremely tolerant or extremophilic, as they can survive on natural and artificial rocks despite being exposed to stressful conditions. RIF have serious negative effects on the appearance and cohesion of rocky substrates, causing the alteration and decomposition of building materials, but also on human and animal health, as they can act as opportunistic pathogens. Their identification is therefore of great importance, especially in urban areas. In the present study, culturing techniques for isolating fungi, and a polyphasic taxonomic approach to their identification, were used to assess the diversity of micromycetes that darken the surfaces of buildings in various villages and cities in Tarragona Province (Spain). Sixty-four species of RIF belonging to forty-one genera were identified, including a new genus (Coccodomyces) and the following six new fungal species: Coccodomyces pleiosporus, Exophiala caementiphila, Exophiala multiformis, Neocatenulostroma spinulosum, Neodevriesia longicatenispora, and Paradevriesia holothallica. Thus, we have established that building materials are ecological niches where a high biodiversity of RIF can develop.
RESUMEN
Chrysosporium is a polyphyletic genus belonging (mostly) to different families of the order Onygenales (Eurotiomycetes, Ascomycota). Certain species, such as Chrysosporium keratinophilum, are pathogenic for animals, including humans, but are also a source of proteolytic enzymes (mainly keratinases) potentially useful in bioremediation. However, only a few studies have been published regarding bioactive compounds, of which the production is mostly unpredictable due to the absence of high-quality genomic sequences. During the development of our study, the genome of the ex-type strain of Chrysosporium keratinophilum, CBS 104.66, was sequenced and assembled using a hybrid method. The results showed a high-quality genome of 25.4 Mbp in size spread across 25 contigs, with an N50 of 2.0 Mb, 34,824 coding sequences, 8002 protein sequences, 166 tRNAs, and 24 rRNAs. The functional annotation of the predicted proteins was performed using InterProScan, and the KEGG pathway mapping using BlastKOALA. The results identified a total of 3529 protein families and 856 superfamilies, which were classified into six levels and 23 KEGG categories. Subsequently, using DIAMOND, we identified 83 pathogen-host interactions (PHI) and 421 carbohydrate-active enzymes (CAZymes). Finally, the analysis using AntiSMASH showed that this strain has a total of 27 biosynthesis gene clusters (BGCs), suggesting that it has a great potential to produce a wide variety of secondary metabolites. This genomic information provides new knowledge that allows for a deeper understanding of the biology of C. keratinophilum, and offers valuable new information for further investigations of the Chrysosporium species and the order Onygenales.
