Cytokinin-to-auxin ratios and morphology of shoots and tissues transformed by a chimeric isopentenyl transferase gene

Tissues transformed with the isopentenyl transferase (ipt) gene cloned from the T-DNA region of the Ti plasmid or with the ipt gene placed under the control of the cauliflower mosaic virus 35S promoter (35S-ipt) were analyzed for auxin and cytokinin. Free and total indole-3-acetic acid (IAA) levels...

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Bibliographic Details
Published in:Plant physiology (Bethesda) 1989-11, Vol.91 (3), p.808-811
Main Authors: Smigocki, A.C. (ARS, USDA, Plant Molecular Biology Laboratory, Beltsville, MD), Owens, L.D
Format: Article
Language:English
Subjects:
ACIDE INDOLACETIQUE
ACIDO INDOLACETICO
Agronomy. Soil science and plant productions
Auxins
Biological and medical sciences
Biotechnology
Cell growth
Communications
CRECIMIENTO
CROISSANCE
Cucumbers
CUCUMIS SATIVUS
Cytokinins
Development and Growth Regulation
Fundamental and applied biological sciences. Psychology
Genes
Genetic engineering
Genetic engineering applications
Genetic technics
Genetics and breeding of economic plants
Insulin antibodies
Methods. Procedures. Technologies
MORFOGENESIS
MORPHOGENESE
NICOTIANA
NICOTIANA TABACUM
Plant breeding: fundamental aspects and methodology
Plant cells
Plant growth regulators
Plant tumor inducing plasmids
Plants
TRANSFERASAS
TRANSFERASE
TRANSFORMACION GENETICA
TRANSFORMATION GENETIQUE
ZEATINA
ZEATINE
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Summary:Tissues transformed with the isopentenyl transferase (ipt) gene cloned from the T-DNA region of the Ti plasmid or with the ipt gene placed under the control of the cauliflower mosaic virus 35S promoter (35S-ipt) were analyzed for auxin and cytokinin. Free and total indole-3-acetic acid (IAA) levels in 35S-ipt-transformed formed Nicotiana tabacum and cucumber cells were reduced by 12 to 78% in comparison to untransformed tissues. In contrast free IAA concentrations in 35S-ipt-transformed Nicotiana plumbaginifolia were almost three times those of untransformed tissues, while total IAA levels were not significantly affected. Cytokinin levels in these antibodies were elevated an average of 300-fold resulting in a 24- to over 2000-fold increase in the cytokinin-to-auxin ratios. High cytokinin-to-auxin ratios correlated with the shooty phenotype of transformed tissues propagated in vitro in the absence of added growth hormones. We conclude that increased endogenous cytokinin-to-auxin ratios can induce cells to undergo morphogenesis and that elevated cytokinin levels can also induce auxin-autonomous growth of transformed tissues without causing a corresponding increase in endogenous IAA levels
ISSN:0032-0889
1532-2548
DOI:10.1104/pp.91.3.808