Differential expression analysis of the SRB1 gene in fluconazole-resistant and susceptible strains of Candida albicans

Abstract

To study differences in SRB1 gene expression between Candida albicans fluconazole-resistant strains and fluconazole-sensitive strains, and to identify new antifungal drug treatment targets. We studied 30 fluconazole-resistant and 47 fluconazole-sensitive C. albicans strains. The strains were routinely cultured, and total RNA was extracted, reverse transcribed into cDNA and analyzed with real-time PCR amplification with 18S rRNA used as an internal reference gene. The expression levels of the two groups were analyzed in Light Cycler system software version 3.0, and independent Student’s t test was performed in SPSS 19.0 statistical software. P < 0.05 was considered to indicate a statistical difference. DNAMAN multiple sequence alignment analysis was used to randomly analyze SBR1 related sequences of four resistant strains and four sensitive strains. An evolutionary tree was constructed with the maximum likelihood method in Mega6.0 software. The mean SRB1 gene expression in the drug-resistant group was 0.75138 × 10^–3, and that in the sensitive group was 1.6664 × 10^–3. Independent Student’s t test indicated a statistically significant difference (T = −3.972, P = 0.000, P < 0.05). DNAMAN multiple sequence alignment analysis showed that the sequence identity of the CDS in the eight strains was 75.17%, and that of sequences 1000 bp upstream of the CDS was 96.35%. Cluster analysis showed that the CDS and sequences 1000 bp upstream of the CDS showed no significant differences between groups. At the mRNA level, the SRB1 gene expression in fluconazole-resistant C. albicans was lower than that in fluconazole-sensitive strains, thus suggesting that the gene may be associated with drug resistance and that the regulatory mechanism leading to this difference is complex.