Uncoupling Auxin and Ethylene Effects in Transgenic Tobacco and Arabidopsis Plants

• Published in: The Plant cell Vol. 5; no. 2; pp. 181 - 189
• Main Authors: Romano, Charles P., Cooper, Mark L., Klee, Harry J.
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01.02.1993
• Subjects: Apical dominance; Auxins; Biological and medical sciences; Ethylene production; Fundamental and applied biological sciences. Psychology; Growth regulators; Insulin antibodies; Metabolism; Overproduction; Plant cells; Plant growth; Plant physiology and development; Plants; Transgenes; Transgenic plants; Auxin; Enzyme; Ethylene; Gene overexpression; Nicotiana tabacum; Tryptophan 2-monooxygenase; Biological activity; Arabidopsis thaliana; Morphogenesis; Investigation method; Cruciferae; Dicotyledones; Angiospermae; Plant growth substance; Spermatophyta; Transgenic plant; Solanaceae; Apical dominance; Elongation
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1105/tpc.5.2.181

Overproduction of auxin in transgenic plants also results in the overproduction of ethylene. Plants overproducing both auxin and ethylene display inhibition of stem elongation and growth, increased apical dominance, and leaf epinasty. To determine the relative roles of auxin and ethylene in these processes, transgenic tobacco and Arabidopsis plants expressing the auxin-overproducing tryptophan monooxygenase transgene were crossed to plants expressing an ethylene synthesis-inhibiting 1-aminocyclopropane-1-carboxylate deaminase transgene. Tobacco and Arabidopsis plants with elevated auxin and normal levels of ethylene were obtained by this strategy. Transgenic auxin-overproducing Arabidopsis plants were also crossed with the ethylene-insensitive ein1 and ein2 mutants. Analysis of these plants indicates that apical dominance and leaf epinasty are primarily controlled by auxin rather than ethylene. However, ethylene is partially responsible for the inhibition of stem elongation observed in auxin-overproducing tobacco. Finally, these data show that auxin overproduction can be effectively uncoupled from ethylene overproduction in transgenic plants to enable direct manipulation of plant morphology for agronomic and horticultural purposes.