title: Emission of ent-kaurene, a diterpenoid hydrocarbon precursor for gibberellins, into the headspace from plants.
abstract: ent-Kaurene is a tetracyclic hydrocarbon precursor for gibberellins (GAs) in plants and fungi. To address whether fungal GA biosynthesis enzymes function in plants, we generated transgenic Arabidopsis plants overexpressing ent-kaurene synthase (GfCPS/KS) from a GA-producing fungus Gibberella fujikuroi. GfCPS/KS catalyzes a two-step reaction corresponding to ent-copalyl diphosphate synthase (CPS) and ent-kaurene synthase (KS) activities in plants. When GfCPS/KS was overexpressed and targeted to plastids, a range of GA-deficient phenotypes of the ga1-3 and ga2-1 mutants (defective in CPS and KS, respectively) were restored to wild type. Unexpectedly, the transgenic lines overproducing GfCPS/KS emitted the GA precursor ent-kaurene into the headspace besides its accumulation in the plant body. When co-cultivated with the ent-kaurene overproducers in a closed environment, the airborne ent-kaurene was able to fully complement the dwarf phenotype of ga1-3 and ga2-1 mutants, but not that of the ga3-1 mutant (defective in ent-kaurene oxidase). These results suggest that ent-kaurene may be efficiently metabolized into bioactive GAs in Arabidopsis when supplied as a volatile. We also provide evidence that ent-kaurene is released in the headspace of wild-type Chamaecyparis obtusa and Cryptomeria japonica plants, suggesting the occurrence of this hydrocarbon GA precursor as a volatile in nature.
authors.affiliation: Course of the Science of Bioresources, United Graduate School of Agricultural Sciences, Iwate University (Yamagata University), Tsuruoka, Yamagata, 997-8555 Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Otsuka
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Kenmoku
authors.forename: Mikihiro
authors.initials: M
authors.lastname: Ogawa
authors.forename: Kazunori
authors.initials: K
authors.lastname: Okada
authors.forename: Wataru
authors.initials: W
authors.lastname: Mitsuhashi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sassa
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kamiya
authors.forename: Tomonobu
authors.initials: T
authors.lastname: Toyomasu
authors.forename: Shinjiro
authors.initials: S
authors.lastname: Yamaguchi
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D017931:DNA Primers; D045786:Diterpenes, Kaurane / Q000378:metabolism*; D005875:Gibberellins / Q000096:biosynthesis*; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; D045786:Diterpenes, Kaurane; D005875:Gibberellins; C002627:kaurene; D019883:Alkyl and Aryl Transferases; C021459:kaurene synthetase