Abstract
We have reported on a cytosolic gibberellin-binding protein (GBP) in adzuki bean (Vigna angularis) seedlings. The GBP showed a high affinity specific to GAs carrying a biological activity. Speculating that the metabolic enzymes for GAs, 2-oxidases (GA2ox) could show a ligand-selectivity similar to the GBP, we cloned GA2ox genes of adzuki bean (VaGA2oxs) and examined the GA-binding characters of their recombinant proteins. VaGA2oxA1 which gene was majorly expressed in the seedlings showed high affinities specific to GAs in active forms like the GBP. However, the antiserum which cross-reacted with all recombinant VaGA2oxs failed to inhibit the interaction of the GBP and GA, suggesting that the adzuki-GBP was different from VaGA2oxs. Recently a cytosolic GA-receptor gene Gibberellin Insensitive Dwarf1 (GID1) was identified from rice. We studied its GA-binding characters and will discuss on the similarity between GID1 and GBP.
