CONTROLLED CYTOKININ PRODUCTION IN TRANSGENIC TOBACCO USING A COPPER-INDUCIBLE PROMOTER

Citation
Mj. Mckenzie et al., CONTROLLED CYTOKININ PRODUCTION IN TRANSGENIC TOBACCO USING A COPPER-INDUCIBLE PROMOTER, Plant physiology, 116(3), 1998, pp. 969-977
Citations number
46
Categorie Soggetti
Plant Sciences
Journal title
ISSN journal
00320889
Volume
116
Issue
3
Year of publication
1998
Pages
969 - 977
Database
ISI
SICI code
0032-0889(1998)116:3<969:CCPITT>2.0.ZU;2-S
Abstract
The cytokinin group of plant hormones regulates aspects of plant growt h and development, including the release of lateral buds from apical d ominance and the delay of senescence. In this work the native promoter of a cytokinin synthase gene (ipn was removed and replaced with a Cu- controllable promoter. Tobacco (Nicotiana tabacum L. cv tabacum) trans formed with this Cu-inducible ipt gene (Cu-ipt) was morphologically id entical to controls under noninductive conditions in almost all lines produced. However, three lines grew in an altered state, which is indi cative of cytokinin overproduction and was confirmed by a full cytokin in analysis of one of these lines. The in vitro treatment of morpholog ically normal Cu-ipt transformants with Cu2+ resulted in delayed leaf senescence and an increase in cytokinin concentration in the one line analyzed. In vivo, inductive conditions resulted in a significant rele ase of lateral buds from apical dominance. The morphological changes s een during these experiments may reflect the spatial aspect of control exerted by this gene expression system, namely expression from the ro ot tissue only. These results confirmed that endogenous cytokinin conc entrations in tobacco transformants can be temporally and spatially co ntrolled by the induction of ipt gene expression through the Cu-contro llable gene-expression system.