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Developmental regulation of the gibberellin pathway in pea shoots


Ross, JJ and Davidson, SE and Wolbang, CM and Bayly-Stark, E and Smith, JJ and Reid, JB, Developmental regulation of the gibberellin pathway in pea shoots, Functional Plant Biology, 30, (1) pp. 83-89. ISSN 1445-4408 (2003) [Refereed Article]

DOI: doi:10.1071/FP02108


To investigate gibberellin (GA) biosynthesis in mature tissue of pea (Pisum sativum L.) in the absence of potentially GA-producing meristematic tissue we grafted wild-type scions to rootstocks of the GA-deficient ls-1 mutant and later decapitated the shoot. After 2 d, decapitated shoots contained as much GA19 (a precursor of the bioactive GA1) as comparable tissue from intact plants, even though applied [14C]GA19 was metabolised rapidly during this time. These results show that the pool size of endogenous GA19 was maintained, probably by de novo GA19 synthesis. We also found that the LS gene, which catalyses an early step in GA biosynthesis, is expressed in mature tissue, as are the shoot-expressed GA 20-oxidase and GA 3-oxidase genes. Nevertheless, mature tissue contained very low levels of GA1 and GA20 compared with immature tissue. Levels of GA19, GA29 and GA8were less affected by tissue age. Metabolism studies using 14C-labelled GAs indicated that mature tissue rapidly converted GA19 to GA20 and GA20 to GA1; the latter step was promoted by IAA. However, the 2-oxidation steps GA1 to GA8, GA29 to GA29 and GA29 to GA29-catabolite appear to proceed very rapidly in mature tissue (regardless of IAA content), and we suggest this is the reason why GA1 and GA20 do not accumulate. This is supported by the high level of expression of a key GA 2-oxidase gene in mature tissue.

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:Davidson, SE (Dr Sandra Davidson)
UTAS Author:Wolbang, CM (Miss Carla Wolbang)
UTAS Author:Bayly-Stark, E (Miss Emma Bayly-Stark)
UTAS Author:Smith, JJ (Ms Jenny Smith)
UTAS Author:Reid, JB (Professor Jim Reid)
ID Code:27817
Year Published:2003
Web of Science® Times Cited:22
Deposited By:Plant Science
Deposited On:2003-08-01
Last Modified:2012-10-29

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