The expression levels of the genes associated with arginine biosynthesis (ARG1, ARG3, ARG4, and ARG5,6) were significantly elevated while CAR1 expression was decreased in the root caries plaques in the RC group compared with those in the sound root surface plaques in the HC group (Fig. 3C), which was in line with the transcriptome analysis in the dual-species biofilms and indicated that the enrichment of the C. albicans arginine biosynthesis pathway played key roles in the development of root caries. The gene discussed is ARG1; the disease is root caries.