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.