Figure 2.

PAOx can be converted to PAA without benzyl glucosinolate hydrolysis.

A) A schematic diagram of PAOx and IAOx metabolism in Arabidopsis. The point of disruption in b2b3 and sur1 is marked in the schematic. The chemical structures shown represent deuterium labeled compound D₅-PAOx and D₅-PAA (the input and expected output of the labeled PAOx feeding assays done with sur1), with the red dots denoting the location of deuterium atoms. B) Representative 3-week-old wild type, cyp79b2 cyp79b3 double mutant (b2b3), and sur1 mutant. Scale bar = 1 cm. C) Indole-3-ylmethyl glucosinolate level in b2b3 and sur1 plants fed with water or IAOx for 24 hours (N=2 for sur1 and N=4 for b2b3). D) Benzyl glucosinolate level in b2b3 and sur1 plants fed with water or PAOx for 24 hours (N=2 for sur1 and N=4 for b2b3). C-E) Data represent mean ± SD. The means were compared by one-way ANOVA, and statistically significant differences (P < 0.05) were identified by Tukey’s test and indicated by letters to represent difference among groups. E) Free PAA content of water-fed and PAOx-fed 2-week-old sur1 seedlings (N=4). F) LC-MS chromatograms for the D₅-PAA standard (bottom) and endogenous D₅-PAA in sur1 seedlings after feeding D₅-PAOx (middle) or water (top).