Nucleotidic variabilty and phylogenetic studies of the ITS1-5.8S-ITS2 locus in Candida tropicalis.

MADRASSI, LUCAS M.; ALVAREZ CECCO, PAULO; MIZGIER, NIKOLA; SALVATIERRA, KARINA

Mendoza

Congreso; XVII Latin American Congress of Genetics; 2019

Latin American Assosiation of Genetics

Yeast species belonging to the genus Candida are the most common human opportunistic pathogens. Invasive fungal infections are often life-threatening, mostly due to inefficient diagnostic methods such as traditional methodologies of identification that are not suitable for rapid nor accurate and reliable identification, leading sometimes to inadequate antifungal therapies. Fungal barcoding seeks the DNA-borne species identification standardization through the use of gene sequences from annotated reference specimens. Internal transcribed spacer regions contained within the nuclear ribosomal repeat unit are one of the most commonly used loci for both species identification and subgeneric phylogenetic inference. It is composed of a conserved, intercalary 5.8S gene, and two variable spacers ITS1 and ITS2 which, jointly or separated, are often species specific. The aim of this study was to explore intraspecific nucleotidic differences within 372 complete ITS1-5.8S-ITS2 sequences of C. tropicalis strains isolated from both clinical and environmental sources downloaded from NCBI Genbank database and infer common haplotypes. MEGA v7.0.26 software was used for sequence edition and phylogenetic tree assembly. Multi-sequence alignments and haplotypes infere were done using DECIPHER and haplotypes R-packages. Haplotypes trees were made with PopArt v1.7. Highlighted, these revealed 3 haplotypes with a frequency > 10% diverging only in 1-3 nucleotides, along with some other small groups. Moreover, phylogenetic analysis demonstrated that this locus is species-specific for C. tropicalis.