Correlation between SAP2 and CAP1 in clinical strains of Candida albicans at planktonic and biofilm states

This study aimed to explore the influences of SAP2 and CAP1 on itraconazole (ITR) resistance of Candida albicans at different states. A total of 10 ITR-resistant strains and 10 ITR-sensitive strains were used for SAP2 sequencing and CAP1 sequencing. SAP2 sequencing showed no missense mutation, and three synonymous mutations. CAP1 gene sequencing identified two missense mutations M140I (8) and K191Q (4), and 14 synonymous mutations G201A (1), A246C (5), C282T (6), G288A (6), C321T (7), A399C (16), C432T (16), C465T (11), G552A (16), G669T (1), G672A (1), G681T (2), T783C (1), and T819A (2). The biofilm formation capacity of resistant C. albicans strains, including the CAP1∆/∆ strain, was stronger. Afterward, real-time quantitative PCR was used to analyze the expression of SAP2 and CAP1. Compared with the sensitive strains, SAP2 and CAP1 expressions were both significantly upregulated in resistant strains at planktonic and biofilm states ( P < 0.05). Compared with the strains at planktonic state, SAP2 was significantly upregulated, while CAP1 was significantly downregulated at biofilm states ( P < 0.05). Additionally, SAP2 expression in the CAP1 knocked down strain of C. albicans was significantly upregulated, and SAP2 expression was evidently downregulated in the CAP1∆/∆ strain at biofilm states compared with that at planktonic states ( P < 0.05). Loss of CAP1 can increase SAP2 level and may influence the biofilm formation of C. albicans, thus increasing ITR resistance of C. albicans.