In silico identification of the oosporein gene cluster in the genome of Victoriomyces antarcticus

• Main Authors: Davolos, Domenico, Ghignone, Stefano, Persiani, Anna Maria, Maggi, Oriana
• Format: Conference Object
• Language: English
• Published: 2020
• Subjects: Antarc*; antarcticus
• Online Access: http://hdl.handle.net/11573/1414916

The peculiar features of Victoriomyces antarcticus (Cephalothecaceae), including the production of red pigments, make this polar microfungus a promising candidate in biotechnology. However, the molecular basis of the majority of its biological aspects has to be yet understood. Here, we report the mitochondrial genome (31.08 Kb, GC % 27.04) and the nuclear genome (24 Mb, GC % 57.89) with annotation of V. antarcticus FBL 165T. Considering the genomes of V. antarcticus and the sequenced species within Sordariomycetes, the close evolutionary relationships of Cephalothecaceae with the Coniochaetaceae is confirmed in a phylogenomic framework. Sequence analyses indicated that V. antarcticus could act as saprobe, processing soil nutrients. In particular, among the CAZymes, the most abundant GHs were cellulases (GH5, GH6, GH45), endo-1,4-ß-glucanases (GH5, GH7), xylanases (GH10), and amylases (GH13_1, GH31, GH133), which can be related to the decomposition of plant biomass. Moreover, a relatively low number (10) of chitinases (GH18) indicated limited lytic activities on the chitin. Among the SM biosynthesis gene clusters identified, a pks cluster had sequence homology as well as synteny conservation with a pks gene cluster present in Beauveria bassiana (Hypocreales) encoding the pathway for the production of the red pigment oosporin, a symmetrical 1-4 dibenzoquinone derivative with different biological activities. The putative oosporein biosynthesis in V. antarcticus begins with a pks, utilizing acetyl-CoA and malonyl-CoA to synthesize orsellinic acid, which is enzymatically hydroxylated and then oxidated to benzenetetrol. The dimerization of the benzenetetrol produces oosporein, which is transported across the cell membrane by a protein encoded in the gene cluster. While the regulation of gene expression remains to be elucidated, our data contribute to the understanding on the evolution of the oosporein gene cluster in Sordariomycetes.