title: Endogenous diterpenes derived from ent-kaurene, a common gibberellin precursor, regulate protonema differentiation of the moss Physcomitrella patens.
abstract: Gibberellins (GAs) are a group of diterpene-type plant hormones biosynthesized from ent-kaurene via ent-kaurenoic acid. GAs are ubiquitously present in seed plants. The GA signal is perceived and transduced by the GID1 GA receptor/DELLA repressor pathway. The lycopod Selaginella moellendorffii biosynthesizes GA and has functional GID1-DELLA signaling components. In contrast, no GAs or functionally orthologous GID1-DELLA components have been found in the moss Physcomitrella patens. However, P. patens produces ent-kaurene, a common precursor for GAs, and possesses a functional ent-kaurene synthase, PpCPS/KS. To assess the biological role of ent-kaurene in P. patens, we generated a PpCPS/KS disruption mutant that does not accumulate ent-kaurene. Phenotypic analysis demonstrates that the mutant has a defect in the protonemal differentiation of the chloronemata to caulonemata. Gas chromatography-mass spectrometry analysis shows that P. patens produces ent-kaurenoic acid, an ent-kaurene metabolite in the GA biosynthesis pathway. The phenotypic defect of the disruptant was recovered by the application of ent-kaurene or ent-kaurenoic acid, suggesting that ent-kaurenoic acid, or a downstream metabolite, is involved in protonemal differentiation. Treatment with uniconazole, an inhibitor of ent-kaurene oxidase in GA biosynthesis, mimics the protonemal phenotypes of the PpCPS/KS mutant, which were also restored by ent-kaurenoic acid treatment. Interestingly, the GA(9) methyl ester, a fern antheridiogen, rescued the protonemal defect of the disruption mutant, while GA(3) and GA(4), both of which are active GAs in angiosperms, did not. Our results suggest that the moss P. patens utilizes a diterpene metabolite from ent-kaurene as an endogenous developmental regulator and provide insights into the evolution of GA functions in land plants.
authors.affiliation: Department of Biochemistry, Okayama University of Science, Okayama 700-0005, Japan. hayashi@dbc.ous.ac.jp
authors.forename: Ken-ichiro
authors.initials: K
authors.lastname: Hayashi
authors.forename: Keisuke
authors.initials: K
authors.lastname: Horie
authors.forename: Yuji
authors.initials: Y
authors.lastname: Hiwatashi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kawaide
authors.forename: Shinjiro
authors.initials: S
authors.lastname: Yamaguchi
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hanada
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Nakashima
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Nakajima
authors.forename: Lewis N
authors.initials: LN
authors.lastname: Mander
authors.forename: Hisakazu
authors.initials: H
authors.lastname: Yamane
authors.forename: Mitsuyasu
authors.initials: M
authors.lastname: Hasebe
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nozaki
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000378:metabolism; D053898:Biosynthetic Pathways / Q000187:drug effects; D019068:Bryopsida / Q000166:cytology* / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation / Q000187:drug effects; D004952:Esters / Q000494:pharmacology; D055786:Gene Knockout Techniques; D017343:Genes, Plant / Q000235:genetics; D018525:Germination / Q000187:drug effects; D005875:Gibberellins / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D007210:Indoleacetic Acids / Q000494:pharmacology; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D013170:Spores / Q000187:drug effects / Q000378:metabolism
chemical_list: D004952:Esters; D005875:Gibberellins; D007210:Indoleacetic Acids; D019883:Alkyl and Aryl Transferases; C105712:ent-kaurene synthetase B