Identification and Characterization of Genetic Loci Associated With Environmental Thermotolerance in Native Strains of Aspergillus salvadorensis (2025)
Loading...
Date
2025-04-12
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
IKR Journal of Agriculture and Biosciences (IKRJAB)
Abstract
Thermotolerance in Aspergillus salvadorensis is based on an integrated network of
molecular and physiological responses activated to heat stress. Genomic analysis
showed open reading frames corresponding to atg1, atg7 and atg8 in genes of the ATG
system (Autophagy-related genes). These participate in the detection of heat-induced
protein damage, autophagosome biogenesis and the recycling of altered
macromolecules, contributing to the maintenance of cellular homeostasis. The
induction of heat shock proteins, particularly Hsp20 and Hsp70, whose overexpression
under high temperatures confirms their function as molecular chaperones, was also
identified. These stabilize partially denatured proteins, prevent their aggregation and
facilitate their functional folding. The presence of HSE-like regulatory sequences (Heat
Shock Elements) in promoter regions supports specific transcriptional activation
dependent on thermal stimulus. The energy component is also decisive. The detection
of ATP synthase subunits, NADPH-dependent enzymes and elements associated with
the AMPK-like pathway (AMP-Activated Protein Kinase) indicates an increase in
energy demand and metabolic monitoring systems. Sustained ATP production is
essential to sustain repair processes, intracellular transport and protein quality control.
Without ATP, fungal cells would not be able to respond to extreme temperatures. Heat
stress increases the generation of reactive oxygen species, which induces the activation
of antioxidant systems such as superoxide dismutase, catalases and peroxidases,
together with NADPH (Nicotinamide Adenine Dinucleotide Phosphate) regeneration
mechanisms, configuring a protective redox response. Experimentally, mycelial growth
decreases progressively and around 50 °C metacaspases associated with regulated cell
death are activated, establishing the physiological limit of thermal tolerance. In
conclusion, heat resistance in A. salvadorensis depends on the coordinated interaction
between autophagy, chaperones, energy regulation, antioxidant defense and structural
remodeling, mechanisms that guarantee its viability in high temperature environments
in summer when El Salvador has a tropical savannah climate
Description
Keywords
Thermotolerance, Aspergillus salvadorensis, Hsp, Metacaspases, Trehalose