Correlation between HU-resistance–gene-expression profile for bulk-selected, HU-tolerant 3D7HU65 parasites and the efficacy of ACT partner drugs against HU-tolerant strains. (A) Correlation between change in EC₅₀ and levels of gene expression of RNR (pfr1, pfr2 and pfr4) and multidrug resistance marker 1 (pfmdr1) genes of HU-tolerant 3D7HU65 parasites analyzed using qRT-PCR. Parental Pf3D7 line (3D7wt) was used as baseline. (B-C) Antiplasmodial activity of current, major antimalarial drugs against 3D7HU65 HU-tolerant parasites. The horizontal bar represents the median and the vertical bar the interquartile range. For the mean comparisons, the Mann-Whitney test was used for the fold-change of EC₅₀ in panels A-C, and Wilcoxon signed rank test for the fold-change of gene expression in panel A.