- Antonio Vásquez Hidalgo*
- Professor Microbiology, School of Medicine, University of El Salvador, San Salvador, El Salvador
- DOI: 10.5281/zenodo.19441688
The present study on Aspergillus uessalvadorensis focuses
on the characterization of the molecular mechanisms that give it a high
adaptive capacity in highly toxic environments. Through a comprehensive genomic
workflow, which included sequencing using high-throughput platforms (Illumina),
expression analysis using qPCR, and functional annotation in bioinformatics
tools such as InterProScan, UniProtKB, tBLASTn, UniRef90, MetaCyc, EggNOG, and
KEGG, it was possible to establish a robust relationship between genomic
sequencing and the organism’s adaptive strategies. The core of this fungus’s
resistance lies in the expansion and specialization of genes associated with
multidrug efflux systems. In particular, the superfamily of ABC transporters
(ATP-Binding Cassette), highly specialized membrane proteins that function as
active expulsion pumps, stands out. These are composed of transmembrane domains
(TMDs), responsible for substrate recognition and transport, and cytoplasmic
nucleotide-binding domains (NBDs), responsible for ATP hydrolysis that drives
the conformational change necessary for transport. In addition, the presence of
transporters belonging to the Major Facilitator Superfamily (MFS) was
identified, which operate through electrochemical gradients. This coexistence
suggests a strategy of functional redundancy and specialization: while ABC
systems participate in the active expulsion of more complex compounds, MFS
transporters contribute to cellular homeostasis and the handling of simpler
metabolites. A relevant finding is the identification of a large protein (~2450
amino acids) that contains conserved domains associated with transport and
regulation. In addition, genes encoding components of the DNA repair system,
such as ABC excinuclease subunits, were detected. Although these are not
directly involved in the efflux of toxic compounds, they play a crucial role in
repairing damage induced by oxidative stress, UV radiation, or other
environmental agents. This shows a comprehensive defense system that combines exclusion
(eflux) mechanisms with tolerance and genomic repair strategies. From an
ecological perspective, factors such as exposure to soils with a high
concentration of heavy metals and the intensive use of fungicides could have
exerted selective pressure, favoring the expansion of these transport systems.
In this sense, the identified transporters would not only be involved in
resistance to antifungal compounds, but also in the regulation of ionic
homeostasis and adaptation to extreme environments. In mechanistic terms, the
operation of ABC transporters can be described as a cyclical process: after the
entry of a potentially toxic compound into the cell, the substrate is
recognized by the transmembrane domains. Subsequently, the NBD domains
hydrolyze ATP (ATP → ADP + Pi), generating the energy necessary to induce a
conformational change in the protein, allowing the active expulsion of the
compound to the outside of the cell. This mechanism is one of the main barriers
to antimicrobial agents. In conclusion, the genomic profile of A.
uessalvadorensis reveals a complex and multifactorial molecular
architecture oriented to survival in adverse environments. However, although
genomic evidence suggests a high potential for resistance, it is imperative to
validate these findings through experimental studies, including gene expression
analysis (qPCR) and phenotypic susceptibility assays. These approaches will
confirm the functional impact of efflux systems and their relevance in clinical
and environmental contexts.
