부산대학교 도서관

Gibberellins are diterpenoid phytohormones that regulate plant growth, and are biosynthesized from a diterpene intermediate, ent-kaurene, which is produced from geranylgeranyl diphosphate via ent-copalyl diphosphate (ent-CDP). The successive 2 cyclization reactions are catalyzed by 2 distinct diterpene synthases, ent-CDP synthase (ent-CPS) and ent-kaurene synthase (KS). Various diterpene synthase genes involved in specialized metabolism were likely created through duplication and neofunctionalization of gibberellin-biosynthetic ent-CPS and KS genes in crops. Brachypodium distachyonis a monocotyledonous species that is a model plant in grasses. We herein found 1 ent-CPS gene homolog BdCPSand 4 tandemly arrayed KS-like genes BdKS1, KSL2, KSL3, and KSL4in the B. distachyongenome, a simpler collection of paralogs than in crops. Phylogenetic and biochemical analyses showed that BdCPSand BdKS1are responsible for gibberellin biosynthesis. BdKSL2and BdKSL3are suggested to be involved in specialized diterpenoid metabolism. Moreover, we restored KS activity of BdKSL2 through amino acid substitution.Graphical AbstractCopy number and diversity of diterpene synthase gene is reduced in the model poaceous grass Brachypodium distachyoncompared with cereals including rice, maize and wheat.