CsALDH3I1 mediates crocetin biosynthesis in vitro. A, HPLC chromatograms (absorbance at 440 nm) of in vitro assays performed for 120 min in the absence (THIO) and presence (CsALDH3I1:THIO) of CsALDH3I1. STANDARD = crocetin dialdehyde authentic standard. In the presence of CsALDH3I1, the crocetin dialdehyde is converted into crocetin (1, trans-isomer, and 2, cis-isomer; Supplemental Fig. S4). B, Time course of crocetin dialdehyde conversion in the presence of CsALDH3I1. Data are averages ± sd of three biological replicates and expressed as fold internal standard (Fold IS).