| Abstract Detail
Hormone Biology Khodakovskaya, M. [1], Vankova, Radomira [2], Li, Aizhen [3], Malbeck, J. [2], Li, Yi. [4], McAvoy, Richard [4]. Changes in the endogenous cytokinin profile of LEACO10.821kb-ipt transgenic chrysanthemum lines correspond with variations in flowering and branching morphology. A total of 26 lines of Dendranthema x grandiflorium ¡®lridon' (chrysanthemum) were transformed with the cytokinin biosynthesis gene, isopentenyl transferase (ipt), under the control of an 821 bp fragment of the LEACO1 gene promoter (from Lycopersicon esculentum). All transgenic lines were grown under both vegetative and generative growth conditions, and phenotypic traits were characterized. The wild type and selected transgenic lines were analyzed for cytokinin composition under both vegetative and generative growth conditions. LEACO10.821kb-ipt transgenic lines exhibited a range of branching habits and internode lengths under vegetative growth conditions. Under generative growth conditions, LEACO10.821kb-ipt transgenic lines exhibited flower bud counts that ranged from a number similar to the wild type up to 10-times higher. Dramatic increases in bud counts were observed even in transgenic lines that displayed a branching morphology similar to the wild type. Increases in flower bud number were associated with delayed bud development and decreased bud diameter. RT-PCR analyses indicated a marked change in ipt gene expression between the most extreme phenotypes observed in this study. In general, transgenic lines accumulated higher concentrations of bioactive, storage-form cytokinins (O-glucosides) and deactivated-form cytokinins (N-glucosides) in generative shoots than in vegetative shoots. Expression of ipt in transgenic lines correlated well with the elevated sum of bioactive cytokinins plus their glucosides and phosphates, under both vegetative and generative growth conditions. Our results suggest the LEACO10.821kb-ipt gene has potential for use in ornamental crop improvement.
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1 - Russian Academy of Sciences, Institute of Biology and Soil Sciences
2 - Academy of Sciences of the Czech Republic, Institute of Experimental Botany, v.v.i.
3 - University of Connecticut, Plant Science, 1390 Storrs Rd, U-4163, Storrs, CT, 06269, USA
4 - University of Connecticut, Plant Science
Keywords:
Cytokinin
ipt gene
chrysanthemum.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P35006
Abstract ID:2549 |
