In vivo gibberellin biosynthesis in endosperm of Sechium edule Sw. seeds

Abstract

Biosynthesis of gibberellins (GAs) was studied in vivo in endosperms of Sechium edule Sw. Exogenous enf-[14C]kaurene was metabolized into four major products: GA12, GA4, GA7 and 16,17-dihydro-16-hydroxy-GA15 alcohol glucoside. Other minor metabolites were also observed including enf-kaurenol and enf-kaurenal. Conversion of enf-[14C]kaurene to eni-kaurenol glucoside by endosperm cell-free preparations in the presence of UDPG was observed. However, the finding was not confirmed in in vivo studies and is probably artifactual. Overall evidence coming from the analysis of endogenous GAs and in vitro and in vivo biosynthetic studies are discussed in relation to the possible existence in the Sechium seeds of a different route, along with the known pathway, branching from enf-kaurene or ent-7-α-hydroxykaurenoic acid and this also leading to biologically active GAs.