Molecular Confirmation of the Linkage between the Rhizopus oryzae CYP51A Gene Coding Region and Its Intrinsic Voriconazole and Fluconazole Resistance

is the most prevalent causative agent of mucormycosis, an increasingly reported opportunistic fungal infection. These Mucorales are intrinsically resistant to - and -active antifungal azole drugs, such as fluconazole (FLC) and voriconazole, respectively. Despite its importance, the molecular mechanisms of its intrinsic azole resistance have not been elucidated yet. The aim of this work was to establish if the genes are uniquely responsible for intrinsic voriconazole and fluconazole resistance in these fungal pathogens. Two genes were identified in the genome. We classified them as and based on their sequence similarity with other known fungal genes. Later, we obtained a chimeric strain harboring a functional gene expressed under the regulation of the wild-type promoter and terminator. The mutant was selected after transformation by using a novel procedure taking advantage of the FLC hypersusceptibility of the deletion mutant used as the recipient strain. The azole susceptibility patterns of the transformants harboring mimicked exactly the azole susceptibility patterns of this mucormycete. The data presented in this work demonstrate that the coding sequence is uniquely responsible for the azole susceptibility patterns.