Figure 3.

Quantification of MpIAA turnover.

(A) Auxin biosynthesis via the indole pyruvic acid pathway is catalyzed by two key enzymes, TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS (TAA1) and YUCCA (YUC). To lower auxin levels in a tissue, these enzymes can be chemically inhibited by l-kynurenine and yucasin, respectively.(B) Time-lapse imaging of MpIAA-mSC-I gemmae pre-treated with 50 μM l-kynurenine and 50 μM yucasin. Upon auxin (1-NAA; 3 μM) treatment, fluorescence rapidly decreases owing to MpIAA-mSC-I degradation.(C) Fitting normalized fluorescence data using a 1-component exponential model results in an MpIAA half-life of 6.5 min. Scale bar, 25 μm.