Transcript levels of the actin-encoding gene, PDR1, MDR1, MDR2, MDR3, and MDR4 in TRF-resistant strains (NUBS21011 and NUBS21012) and TRF-susceptible strains (N45 and N46) of T. rubrum. All strains were cultured in SDB containing 0.05 μg/mL ITZ for 3 h at 28°C. Expression levels of all genes were normalized to that of the actin-encoding gene and are expressed as a relative quantity.