SEQUENCING AND PRELIMINARY ANALYSIS OF GENES INVOLVED IN IRON METABOLISM IN CANDIDA AFRICANA CBS11016 STRAIN

In this study we report a molecular characterization including differential gene expression analysis of the transcription factor (AFT2) and other genes involved in the uptake (FTR1) and oxidation (FET3, FET31, FET33 FET34, FET99) of iron in C. africana, a less pathogenic biovariant of the well-known human pathogen C. albicans. The type strain C. africana CBS11016 and the C. albicans WO-1 strain were used for specific phenotypic and genetic analysis. For phenotypic tests, the strains were grown on YPD agar containing different concentrations (80,150, 200 and 500 µM) of bathophenanthrolinedisulfonate (BPS). From each strain, DNA and total RNA were extracted according to standard protocols and used for sequencing and qPCR analysis of the genes listed above. The results revealed that CBS11016 and WO-1 strains were able to growth in YPD+80 µM BPS, but at higher concentrations C. africana showed a reduced growth and a hyperfilamentous phenotype if compared to C. albicans. DNA sequence analysis showed a number of characteristic nucleotide substitutions in all examined genes. Moreover, FET34 and AFT2 genes showed also a specific deletion of three and six nucleotides respectively. No transcriptional differences were observed among the two Candida strains examined. Only the FET99 gene was significantly down-regulated in the CBS11016 strain. Unlike C. albicans, C. africana shows a retarded growth when cultured in iron deficient conditions and this appears not be exclusively linked to genes involved in the iron metabolism. Therefore further analysis are needed to elucidate the molecular network related to iron utilization in C. africana.