+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Cloning and overproduction of gibberellin 3-oxidase in hybrid aspen trees. Effects on gibberellin homeostasis and development



Cloning and overproduction of gibberellin 3-oxidase in hybrid aspen trees. Effects on gibberellin homeostasis and development



Plant Physiology 135(1): 221-230



To broaden our understanding of gibberellin (GA) biosynthesis and the mechanism whereby GA homeostasis is maintained in plants, we have investigated the degree to which the enzyme GA 3-oxidase (GA3ox) limits the formation of bioactive GAs in elongating shoots of hybrid aspen (Populus tremula x Populus trenuloides). We describe the cloning of a hybrid aspen GA3ox and its functional characterization, which confirmed that it has 3beta-hydroxylation activity and more efficiently converts GA, to GA4 than GA20 to GA1. To complement previous studies, in which transgenic GA 20-oxidase (GA20ox) overexpressers were found to produce 20-fold higher bioactive GA levels and subsequently grew faster than wild-type plants, we overexpressed an Arabidopsis GA3ox in hybrid aspen. The generated GA3ox overexpresser lines had increased 3beta-hydroxylation activity but exhibited no major changes in morphology. The nearly unaltered growth pattern was associated with relatively small changes in GA1 and GA4 levels, although tissue-dependent differences were observed. The absence of increases in bioactive GA levels did not appear to be due to feedback or feed-forward regulation of dioxygenase transcripts, according to semiquantitative reverse transcription polymerase chain reaction analysis of PttGA20ox1, PttGA3ox1, and two putative PttGA2ox genes. We conclude that 20-oxidation is the limiting step, rather than 3beta-hydroxylation, in the formation of GA1 and GA4 in elongating shoots of hybrid aspen, and that ectopic GA3ox expression alone cannot increase the flux toward bioactive GAs. Finally, several lines of evidence now suggest that GA4 has a more pivotal role in the tree hybrid aspen than previously believed.

Please choose payment method:






(PDF emailed within 0-6 h: $19.90)

Accession: 004076372

Download citation: RISBibTeXText

PMID: 15122019

DOI: 10.1104/pp.104.038935


Related references

Cloning and Overproduction of Gibberellin 3-Oxidase in Hybrid Aspen Trees. Effects on Gibberellin Homeostasis and Development. Plant Physiology 135(1): 221-230, 2004

Expression cloning of a gibberellin 20-oxidase, a multifunctional enzyme involved in gibberellin biosynthesis. Proceedings of the National Academy of Sciences of the United States of America 91(18): 8552-8556, 1994

Gibberellin homeostasis in tobacco is regulated by gibberellin metabolism genes with different gibberellin sensitivity. Plant and Cell Physiology 49(5): 679-690, 2008

Daylength and spatial expression of a gibberellin 20-oxidase isolated from hybrid aspen (Populus tremula L. P. tremuloides Michx.). Planta 214(6): 920-930, 2002

Daylength and spatial expression of a gibberellin 20-oxidase isolated from hybrid aspen (Populus tremula L. x P. tremuloides Michx.). Planta 214(6): 920-930, 2002

Biosynthesis of gibberellin a 12 gibberellin a 15 gibberellin a 24 gibberellin a 36 and gibberellin a 37 by a cell free system from cucurbita maxima. Phytochemistry 13(8): 1433-1440, 1974

Transcriptional changes of gibberellin oxidase genes in grapevines with or without gibberellin application during inflorescence development. Journal of Plant Research 127(2): 359-371, 2014

Gibberellin 3-oxidase gene expression patterns influence gibberellin biosynthesis, growth, and development in pea. Plant Physiology 163(2): 929-945, 2014

Gibberellin 3-oxidase Gene Expression Patterns Influence Gibberellin Biosynthesis, Growth, and Development in Pea. Plant Physiology 163(2): 929-945, 2013

Modification of gibberellin production and plant development in Arabidopsis by sense and antisense expression of gibberellin 20-oxidase genes. Plant Journal 17(5): 547-556, 1999

Fungal products part 9 gibberellin a 16 gibberellin a 36 gibberellin a 37 gibberellin a 41 and gibberellin a 42 from gibberella fujikuroi. Journal of the Chemical Society Perkin Transactions I 22: 2824-2830, 1973

Transgenic hybrid aspen trees with increased gibberellin (GA) concentrations suggest that GA acts in parallel with FLOWERING LOCUS T2 to control shoot elongation. New Phytologist 205(3): 1288-1295, 2016

Gibberellins 89. synthesis of gibberellin a 55 and gibberellin a 57 as well as 1 oxygenated gibberellin a 5 and gibberellin a 20 analogs a new principle for the regioselective transposition of an allylic alcohol function. Tetrahedron 39(3): 449-454, 1983

Influence of light treatment on gibberellin gibberellin a 4 gibberellin a 7 and gibberellin a 9 content of lactuca sativa cultivar grand rapids achenes. Zeitschrift fuer Pflanzenphysiologie 101(3): 189-194, 1981

Activity of the aldehyde and alcohol of gibberellin a 12 and gibberellin a 14 2 derivatives of gibberellin a 15 and 4 decomposition products of gibberellin a 3 in 13 plant bioassays. Planta (Heidelberg) 130(2): 113-120, 1976