59.苔類ツツソロイゴケにおけるジテルペン環化酵素(口頭発表)

概要

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Gibberellin (GA) is an important plant hormone regulating many aspects of plant growth. The biosynthesis, signaling, and physiological roles have been extensively investigated. In contrast, the biosynthetic pathway and physiological roles of GAs in the liverwort and moss (Bryophyta) have been unclear till now. The investigation of biosynthesis of GAs in a bryophyta not only would provide a new insight into the evolution of plant biosynthesis among land plants, but also would lead to our understanding of physiological GA actions in a Bryophyta. Ent-kaurene is a key intermediate in GA biosynthesis. We had identified a bifunctional ent-kaurene synthase (PpCPS/KS) gene from the moss Physcomitrellapatens. This enzyme directly converted geranylgeranyl diphosphate(GGDP) to ent-kamene and ent-16α-hydroxykaurene via ent-coparyl diphosphate(ent-CDP). Here , we describe the cloning and functional analysis of a bifunctional ent-kaurene synthase (JsCPS/KS) from liverwort Jungermannia subulata. The JsCPS/KS cDNA encoded 886 A.A. as an ORF and showed high similarity to PpCPS/KS. The JsCPS/KS function was analyzed with the in vitro protein synthesis system. GC-MS analysis demonstrated that JsCPS/KS directly converted GGDP to ent-kamene, but not to hydroxykaurenes. Mutational study of JsCPS/KS confirmed that JsCPS/KS catalyzes two-step cyclization from GGDP to ent-kaurene via ent-CDP as a reaction intermediate.
植物化学調節学会の論文
2007-10-05