Gibberellin A12 is converted to gibberellin A53 in cultured cells of Nicotiana tabacum and Catharanthus roseus

Abstract

The metabolism of GA12 and its precursors was investigated in cultured cells of seven cell lines of Nicotiana tabacum and three cell lines of Catharanthus roseus using l4C-labeled substrates. The presence of a metabolic pathway from ent-7α-hydroxykaurenoic acid to GA53 via GA12-aldehyde and GA12 was demonstrated in the cultured cells. GA12 was effectively converted to GA53 in cells of BY-2, 2b-4, 2b-13 and CG from N. tabacum. By contrast, GA53 was not converted to any other GAs in all of the lines of cells examined. The metabolism of C19-GAs was also examined using 3H-labeled substrates. The conversion of GA20 to GA29 and GA, and of GA4 to GA34 occurred more efficiently in cells from C. roseus than in cells from N. tabacum. However, 13-hydroxylation of GA4 and GA9 was not observed in any of the cell cultures examined. Among the various metabolites, GA53, GA29 and GA34 were identified by full-scan GC/MS.