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Evidence that auxin promotes gibberellin A1 biosynthesis in pea


Ross, JJ and O'Neill, DP and Smith, JJ and Kerckhoffs, LH and Elliott, RC, Evidence that auxin promotes gibberellin A1 biosynthesis in pea, The Plant Journal, 21, (6) pp. 547-552. ISSN 0960-7412 (2000) [Refereed Article]

DOI: doi:10.1046/j.1365-313x.2000.00702.x


In shoots of the garden pea, the bioactive gibberellin (GA 1) is synthesised from GA 20, and the enzyme which catalyses this step (a GA 3-oxidase-PsGA3ox1) is encoded by Mendel's LE gene. It has been reported previously that decapitation of the shoot (excision of the apical bud) dramatically reduces the conversion of [ 3H]GA 20 to [ 3H]GA 1 in stems, and here we show that endogenous GA 1 and PsGA3ox1 transcript levels are similarly reduced. We show also that these effects of decapitation are completely reversed by application of the auxin indole-3-acetic acid (IAA) to the 'stump' of decapitated plants. Gibberellin A 20 is also converted to an inactive product, GA 29, and this step is catalysed by a GA 2-oxidase, PsGA2ox1. In contrast to PsGA3ox1, PsGA2ox1 transcript levels were increased by decapitation and reduced by IAA application. Decapitation and IAA treatment did not markedly affect the level of GA 1 precursors. It is suggested that in intact pea plants, auxin from the apical bud moves into the elongating internodes where it (directly or indirectly) maintains PsGA3ox1 transcript levels and, consequently, GA 1 biosynthesis.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Plant biology
Research Field:Plant physiology
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the environmental sciences
UTAS Author:Ross, JJ (Associate Professor John Ross)
UTAS Author:O'Neill, DP (Mr Damian O'Neill)
UTAS Author:Smith, JJ (Ms Jenny Smith)
UTAS Author:Kerckhoffs, LH (Dr Leonardus Kerckhoffs)
UTAS Author:Elliott, RC (Dr Robert Elliott)
ID Code:20581
Year Published:2000
Web of Science® Times Cited:198
Deposited By:Plant Science
Deposited On:2000-08-01
Last Modified:2011-08-04

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