Figure 2.

 Identification of UGT74E2 as an IBA Glucosyltransferase.

(A) Relative conversion rates of different plant hormones to their glucosylated form by recombinant UGT74E2. The naturally occurring auxin IBA is the preferred substrate. Error bars are se (n = 2). JA, jasmonic acid.

(B) Separation by liquid chromatography of buffered samples containing UDP-Glc and IBA without (left) and with (right) addition of recombinant UGT74E2. Peak identity was determined by mass spectrometry. A significant proportion of IBA was glucosylated only in the presence of UGT74E2.

(C) Separation by liquid chromatography of buffered samples containing UDP-Glc and IAA (top) or IBA (bottom) in short-term incubation assays (10 min). No IAA-Glc could be detected, whereas a significant proportion of IBA was glucosylated.