Abstract:
Aspergillus section Circumdati encompasses several species that express both beneficial
(e.g., biochemical transformation of steroids and alkaloids, enzymes and metabolites) and harmful
compounds (e.g., production of ochratoxin A (OTA)). Given their relevance, it is important
to analyze the genetic and metabolic diversity of the species of this section. We sequenced the
genome of Aspergillus affinis CMG 70, isolated from sea water, and compared it with the genomes of
species from section Circumdati, including A. affinis’s strain type. The A. affinis genome was characterized
considering secondary metabolites biosynthetic gene clusters (BGCs), carbohydrate-active
enzymes (CAZymes), and transporters. To uncover the biosynthetic potential of A. affinis CMG
70, an untargeted metabolomics (LC-MS/MS) approach was used. Cultivating the fungus in the
presence and absence of sea salt showed that A. affinis CMG 70 metabolite profiles are salt dependent.
Analyses of the methanolic crude extract revealed the presence of both unknown and well-known
Aspergillus compounds, such as ochratoxin A, anti-viral (e.g., 3,5-Di-tert-butyl-4-hydroxybenzoic acid
and epigallocatechin), anti-bacterial (e.g., 3-Hydroxybenzyl alcohol, L-pyroglutamic acid, lecanoric
acid), antifungal (e.g., L-pyroglutamic acid, 9,12,13-Trihydroxyoctadec-10-enoic acid, hydroxyferulic
acid), and chemotherapeutic (e.g., daunomycinone, mitoxantrone) related metabolites. Comparative
analysis of 17 genomes from 16 Aspergillus species revealed abundant CAZymes (568 per species),
secondary metabolite BGCs (73 per species), and transporters (1359 per species). Some BGCs are
highly conserved in this section (e.g., pyranonigrin E and UNII-YC2Q1O94PT (ACR toxin I)), while
others are incomplete or completely lost among species (e.g., bikaverin and chaetoglobosins were
found exclusively in series Sclerotiorum, while asperlactone seemed completely lost). The results of
this study, including genome analysis and metabolome characterization, emphasize the molecular
diversity of A. affinis CMG 70, as well as of other species in the section Circumdati.
Description:
SUPPLEMENTARY MATERIAL : Table S1: Gene annotation, Table S2: Carbohydrate active enzymes prediction, Table S3: Secreted proteins, Table S4: Transporter’s prediction, Table S5: Biosynthetic Gene Clusters, Table S6: Summary of genomic features of Circumdati genomes, Table S7: Comparison of CAZymes families between A. affinis CMG 70 and ATCC MYA-4773, Table S8: Full list of compounds, Table S9: List of the significantly differential compounds, File S1: matched spectral library compounds.
