The Arabidopsis GA1 locus encodes the cyclase ent-kaurene synthetase A of gibberellin biosynthesis.

Sun, Tai-ping; Kamiya, Yûji

doi:10.1105/tpc.6.10.1509

Cited by 451 publications

(252 citation statements)

References 32 publications

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“…Therefore, we used a strong allele of ga1 (Koornneef 1978;Dubreucq et al 1996), de®cient for the GA-biosynthetic enzyme ent-kaurene synthase (Sun and Kamiya 1994), which allowed us to look at the eect of much lower concentrations than in previous experiments.…”

Section: Gibberellins Are Required For Normal Endoreduplicationmentioning

confidence: 99%

Gibberellin and ethylene control endoreduplication levels in the Arabidopsis thaliana hypocotyl

Gendreau

Orbović

Höfte

et al. 1999

Planta

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We have previously shown that endoreduplication levels in hypocotyls of Arabidopsis thaliana (L.) Heynh. are under negative control of phytochromes. In this study, the hormonal regulation of this process was analysed using a collection of A. thaliana mutants. The results show that two hormones in particular, gibberellin (GA) and ethylene, play distinct roles. Hypocotyl cells of the GA-deficient mutant ga1-11 grown in the dark did not elongate and showed a greatly reduced endoreduplication. Normal endoreduplication could be restored by supplying 10(-9) M of the gibberellin GA(4+7), whereas the restoration of normal cell growth required 100-fold higher concentrations. The GA-insensitive mutant gai showed reduced cell elongation but normal ploidy levels. We conclude that (i) GA(4+7) has a global positive effect on endoreduplication and (ii) that endoreduplication is more sensitive to GA(4+7) than cell elongation. Ethylene had a completely different effect. It induced an extra round of endoreduplication both in light- and dark-grown seedlings and acted mainly on discrete steps rather than having a global effect on endoreduplication. The genes EIN2 and CTR1, components of the ethylene signal transduction pathway were both involved in this process.

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Section: Gibberellins Are Required For Normal Endoreduplicationmentioning

confidence: 99%

Gibberellin and ethylene control endoreduplication levels in the Arabidopsis thaliana hypocotyl

Gendreau

Orbović

Höfte

et al. 1999

Planta

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“…Two discrete enzymes, ent-copalyl diphosphate synthase (CPS) and ent-kaurene synthase (KS), are used by plants and bacteria for the transformation of GGPP via ent-copalyl diphosphate (4, ent-CPP) to 5. [5][6][7] In F. fujikuroi and two additional fungal producers, a bifunctional terpene cyclase with two domains (CPS/KS) catalyses the consecutive cyclisation of GGPP to 5 (Scheme 2). [1,8] Downstream steps include the oxidation by the cytochrome P450-4 monooxygenase sequentially furnishing ent-kaurenol (6), entkaurenal (7), and ent-kaurenoic acid (8).…”

Section: Introductionmentioning

confidence: 99%

Biosynthesis of Sesqui‐ and Diterpenes by the Gibberellin Producer Fusarium fujikuroi

Brock¹,

Tudzynski²,

Dickschat³

2011

ChemBioChem

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The fungus Fusarium fujikuroi IMI58289 emits a complex pattern of volatile terpenoids including two major compounds, the sesquiterpene alcohol α-acorenol and the diterpene ent-kaurene. ent-Kaurene is the precursor for the phytohormone gibberellic acid (GA(3)) and is produced from geranylgeranyl diphosphate (GGPP) via ent-copalyl diphosphate by the bifunctional ent-copalyl diphosphate/ent-kaurene synthase (CPS/KS). Several structurally related diterpenes were identified as side products of the CPS/KS. Deletion of the cps/ks gene or the whole GA(3) biosynthetic gene cluster resulted in completely abolished diterpene production. Mutants with deletions of the cytochrome P450 monooxygenase gene P450-4, which is responsible for the three oxidation steps from ent-kaurene to ent-kaurenoic acid en route to GA(3), accumulate diterpene hydrocarbons. Feeding with [6,6,6-(2) H(3)] mevalonolactone gave insights into the stereochemistry of the GGPP cyclisation, which operates with a chair-chair-"antipodal" fold. A rational biosynthetic scheme for all identified sesquiterpenes demonstrated their formation from farnesyl diphosphate (FPP) via three alternative initial cyclisations. Genome sequencing revealed the presence of five putative sesquiterpene synthase genes in the F. fujikuroi genome. The structures of several trace compounds from other classes have been identified as new natural products; these were delineated from their mass spectra and unambiguously assigned by comparison to synthetic references.

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“…However, these transgenic plants exhibited undesirable morphologies known as the hairy root syndrome (Spena et al 1987) in addition to dwarfness. Gibberellins (GAs) play a key role in the regulation of many aspects of plant growth and development including internode elongation, leaf expansion and transition from vegetative growth to flowering (Koornneef and van der Veen 1980;Sun and Kamiya 1994;Wilson et al 1992). In higher plants, GAs are catalyzed and metabolized by several different GA oxidases, which control the endogenous level of bioactive GAs (Hedden and Kamiya 1997;Hedden and Phillips 2000;Lange 1998).…”

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confidence: 99%

Horticultural characterization of a tetraploid transgenic plant of <i>Tricyrtis</i> sp. carrying the gibberellin 2-oxidase gene

Ôtani

Ishibe

Inthima

et al. 2014

Plant Biotechnology

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The gibberellin 2-oxidase catalyzes the bioactive gibberellins or their immediate precursors to inactive forms. We have previously produced transgenic plants of the liliaceous plant Tricyrtis sp. containing the GA2ox gene from the linderniaceous plant Torenia fournieri. These transgenic plants showed dwarf phenotypes as expected but unfortunately had no flowers or only small, unopened flowers. Recently, one newly produced transgenic line (G2-55) formed fully opened flowers. G2-55 showed a moderately dwarf phenotype and the shoot length decreased to 63.4% of that of the control, non-transgenic plants. No significant differences in the number of flowers per shoot and in the flower size were observed between G2-55 and the control. Flow cytometry analysis and chromosome observation showed that G2-55 was tetraploid (2n=4x=52), whereas the other transgenic lines producing no or only small flowers were diploid (2n=2x=26) as the mother plant. Pollen fertility of G2-55 was 81.2% as determined by acetocarmine staining. The tetraploidy in G2-55 might be resulted from somaclonal variation of embryogenic calluses used as a target material for Agrobacterium-mediated transformation. The tetraploid transgenic plant G2-55 may be useable not only directly as a potted plant, but also as a material for further breeding of Tricyrtis spp.

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The Arabidopsis GA1 locus encodes the cyclase ent-kaurene synthetase A of gibberellin biosynthesis.

Cited by 451 publications

References 32 publications

Gibberellin and ethylene control endoreduplication levels in the Arabidopsis thaliana hypocotyl

Gibberellin and ethylene control endoreduplication levels in the Arabidopsis thaliana hypocotyl

Biosynthesis of Sesqui‐ and Diterpenes by the Gibberellin Producer Fusarium fujikuroi

Horticultural characterization of a tetraploid transgenic plant of <i>Tricyrtis</i> sp. carrying the gibberellin 2-oxidase gene

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