The Diageotropica gene differentially affects auxin and cytokinin responses throughout development in tomato

• Published in: Plant physiology (Bethesda) 1998-05, Vol.117 (1), p.63-72
• Main Authors: Coenen, C. (Oregon State University, Corvallis, OR.), Lomax, T.L
• Format: Article
• Language: English
• Subjects: 2,4-D; 2,4-Dichlorophenoxyacetic Acid - pharmacology; 6-BENZILADENINA; 6-BENZYLADENINE; Agronomy. Soil science and plant productions; AHILAMIENTO; ANATOMIA DE LA PLANTA; ANATOMIE VEGETALE; APTITUD REGENERATIVA; APTITUDE A LA REGENERATION; Auxins; Biological and medical sciences; BIOSINTESIS; BIOSYNTHESE; BIOSYNTHESIS; CAL; CALLO; CALLUS; Chemical agents; CRECIMIENTO; CROISSANCE; Cross resistance; CULTIVO DE TEJIDOS; CULTURE DE TISSU; Culture Media; Culture Techniques; Cytokinins; Cytokinins - pharmacology; Development and Growth Regulation; DEVELOPMENTAL STAGES; DOSAGE EFFECTS; Dose-Response Relationship, Drug; Economic plant physiology; EFECTOS DE DOSIFICACION; EFFET DOSE; ETAPAS DE DESARROLLO; ETAPAS DE DESARROLLO DE LA PLANTA; ETHYLENE; Ethylenes - biosynthesis; ETILENO; ETIOLATION; ETIOLEMENT; EXPLANT; EXPLANTES; EXPLANTS; Fundamental and applied biological sciences. Psychology; GENETIC VARIATION; GROWTH; Growth and development; HIPOCOTILOS; Hormones; Hypocotyl - drug effects; Hypocotyl - genetics; Hypocotyl - growth & development; HYPOCOTYLE; HYPOCOTYLS; Indoleacetic Acids - metabolism; Indoleacetic Acids - pharmacology; INTERACTIONS; LYCOPERSICON ESCULENTUM; Lycopersicon esculentum - drug effects; Lycopersicon esculentum - genetics; Lycopersicon esculentum - growth & development; Morphogenesis, differentiation, rhizogenesis, tuberization. Senescence; Mutation; PLANT ANATOMY; PLANT DEVELOPMENTAL STAGES; Plant growth regulators; Plant Growth Regulators - biosynthesis; Plant Growth Regulators - pharmacology; Plant physiology and development; Plant roots; Plant Roots - drug effects; Plant Roots - genetics; Plant Roots - growth & development; Plant Shoots - drug effects; Plant Shoots - genetics; Plant Shoots - growth & development; Plants; PLANTULAS; PLANTULE; RACINE; RAICES; REGENERATIVE ABILITY; REGULATION; ROOTS; SEEDLINGS; SIGNALS; Space life sciences; STADE DE DEVELOPPEMENT; STADE DE DEVELOPPEMENT VEGETAL; TISSUE CULTURE; VARIACION GENETICA; VARIATION GENETIQUE; Vegetative apparatus, growth and morphogenesis. Senescence; WILD STRAINS
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.117.1.63

The interactions between the plant hormones auxin and cytokinin throughout plant development are complex, and genetic investigations of the interdependency of auxin and cytokinin signaling have been limited. We have characterized the cytokinin sensitivity of the auxin-resistant diageotropica (dgt) mutant of tomato (Lycopersicon esculentum Mill.) in a range of auxin- and cytokinin-regulated responses. Intact, etiolated dgt seedlings showed cross-resistance to cytokinin with respect to root elongation, but cytokinin effects on hypocotyl growth and ethylene synthesis in these seedlings were not impaired by the dgt mutation. Seven-week-old, green wild-type and dgt plants were also equally sensitive to cytokinin with respect to shoot growth and hypocotyl and internode elongation. The effects of cytokinin and the dgt mutation on these processes appeared additive. In tissue culture organ regeneration from dgt hypocotyl explants showed reduced sensitivity to auxin but normal sensitivity to cytokinin, and the effects of cytokinin and the mutation were again additive. However, although callus induction from dgt hypocotyl explants required auxin and cytokinin, dgt calli did not show the typical concentration-dependent stimulation of growth by either auxin or cytokinin observed in wild-type calli. Cross-resistance of the dgt mutant to cytokinin thus was found to be limited to a small subset of auxin- and cytokinin-regulated growth processes affected by the dgt mutation, indicating that auxin and cytokinin regulate plant growth through both shared and separate signaling pathways