Variability of the secondary structure of ITS2 region of rDNA as a diagnostic marker for non-marneffei species of the genus Talaromyces

DOI: https://doi.org/10.7124/FEEO.v38.1821
Keywords: non-marneffei species, Talaromyces C. R. Benj., ribosomal DNA, ITS2 region, secondary DNA structure

Abstract

Aim. Identifying the causative agents of fungemia belonging to the microscopic fungi of the genus Talaromyces C. R. Benj. remains a difficult task today. Therefore, the aim of this study was to investigate the variability of the secondary structure of the ITS2 region of ribosomal DNA of potential non-marneffei causative agents of talaromycosis based on the analysis of consensus models and to determine the possibility of its use as an additional phylogenetic marker. Methods. The study used methods of comparative analysis of primary DNA sequences, construction of their secondary structure based on minimum free energy (MFE RNAfold), and analysis of conservative structures and mutation points (ITS2 Database). Results. It was determined that the ITS2 region of the studied species consists of 153–158 bp. It was established that secondary structure models constructed using the MFE method form three classic ITS2 hairpins. Mutations in the sequence of the second loop from the 5' end of the structure are considered decisive for the identification of the studied species Talaromyces. Conclusions. The secondary structure of the ITS2 region of rDNA can be used as an additional marker in the molecular identification of known non-marneffei pathogens of talaromycosis.

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