Evidence for the direct 2beta- and 3beta-hydroxylation of [2H2]GA20-13-O-[6'-2H2]glucoside in seedlings of Phaseolus coccineus.
[17-2H2]GA20-13-O-[6'-2H2]glucoside was synthesized and applied to seedlings of Phaseolus coccineus L. After incubation for 72 h the conjugate metabolites were purified and shown by LC-ESI-tandem-MS and GC-MS to be [17-2H2]GA1-13-O-[6'-2H2]glucoside and [17-2H2]GA29-13-O-[6'-2H2]glucoside. This is the first evidence for the conversion of intact GA-O-glucosides, and represents an additional metabolic pathway of the gibberellin metabolism in P. coccineus L. The results indicate that intact GA-O-glucosides are accepted by 2- and 3-oxidases in the plant.