Elsevier

Developmental Biology

Volume 153, Issue 2, October 1992, Pages 386-395
Developmental Biology

Full paper
Altered morphology in transgenic tobacco plants that overproduce cytokinins in specific tissues and organs

https://doi.org/10.1016/0012-1606(92)90123-XGet rights and content

Abstract

An auxin-inducible bidirectional promoter from the soybean SAUR gene locus was fused to a reporter gene in one direction and a cytokinin biosynthetic gene in the opposite direction and the expression of these fused genes was examined in transgenic tobacco. The Escherichia coli uidA gene, which encodes the enzyme β-glucuronidase (GUS), was used as the reporter gene and the Agrobacterium tumefaciens ipt gene, which encodes the enzyme isopentenyl transferase, was used as the cytokinin biosynthetic gene. These constructs allowed the overproduction of cytokinins in tobacco in a tissue- and organ-specific manner. Localized overproduction of cytokinins was monitored using the GUS reporter gene and measured by an ELISA assay. The tissue- and organ-specific overproduction of cytokinins produced a number of morphological and physiological changes, including stunting, loss of apical dominance, reduction in root initiation and growth, either acceleration or prolonged delayed senescence in leaves depending on the growth conditions, adventitious shoot formation from unwounded leaf veins and petioles, altered nutrient distribution, and abnormal tissue development in stems. While some of these morphological changes result directly from the localized overproduction of cytokinins, other changes probably result from the mobilization of plant nutrients to tissues rich in cytokinins.

References (26)

  • M. Bevan

    Binary Agrobacterium vectors for plant transformation

    Nucl. Acids Res

    (1984)
  • R.M. Devlin et al.

    Plant Physiology

  • J.J. Estruch et al.

    Viviparous leaves produced by somatic activation of an inactive cytokinin-synthesizing gene

    Science

    (1991)
  • M.A. Gee et al.

    Tissue-specific and organ-specific expression of soybean auxin-responsive transcripts GH3 and SAURs

    Plant Cell

    (1991)
  • G. Hagen et al.

    Auxin-induced expression of the soybean GH3 promoter in transgenic tobacco plants

    Plant Mol. Biol

    (1991)
  • F. Heidekamp et al.

    Nucleotide sequence of the Agrobacterium tumefaciens octapine Ti plasmid-encoded tmr gene

    Nucl. Acids Res

    (1983)
  • M. Holden

    Chlorophylls

  • R. Horgan

    Analytical procedures for cytokinins

  • R. Horgan

    Cytokinins

  • R.A. Jefferson

    Assaying for chimeric genes in plants: The GUS fusion system

    Plant Mol. Biol. Rep

    (1987)
  • H. Klee et al.

    Molecular genetic approaches to plant hormone biology

    Annu. Rev. Plant Physiol. Plant Mol. Biol

    (1991)
  • Y. Li et al.

    An auxin-responsive promoter is differentially induced by auxin gradients during tropisms

    Plant Cell

    (1991)
  • B.A. McClure et al.

    Characterization of a class of small auxin-inducible polyadenylated RNAs

    Plant Mol. Biol

    (1987)
  • Cited by (0)

    This work was supported by Grant DCB 8904493 from the National Science Foundation (to T.J.G. and G.H.). This paper is No. 11,649 of the Journal Series of the Missouri Agricultural Experiment Station.

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