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Genetic Manipulation of Gibberellin (GA) Oxidase Genes in Nicotiana sylvestris using constitutive promoter to modify Plant Architecture

Author Affiliations

  • 1 Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK 2BBIO, Jai Research Foundation, Vapi, Gujarat, INDIA
  • 2

Res. J. Recent Sci., Volume 1, Issue (5), Pages 1-7, May,2 (2012)


Gas is a large group of tetracyclic diterprenoid carboxylic acids. Gibberellins (GAs) control many aspects of plant development, including plant development, flowering, leaf expansion and growth. Leaf explants of Nicotiana sylvestris (Solanaceae) were used for Agrobacterium-mediated delivery of a range of GA-biosynthetic genes to determine the influence of their encoded enzymes on the production of bioactive GAs and plant stature in this species. Constructs were prepared containing the nptII gene for kanamycin resistance as a selectable marker, and the GA-biosynthetic genes, their expression under the control of the CaMV 35S promoter. The GA-biosynthetic genes comprised of PcGA2ox1 isolated from Phaseolus coccineus, and, is specific for C19-GAs and 2β-hydroxylates the bioactive GAs i.e. GA1 and GA4 and their immediate precursors GA20 and GA9, respectively. AtGA20ox1, isolated from Arabidopsis thaliana, the product from which catalyses the formation of C19-GAs, and MmGA3ox1 and MmGA3ox2, isolated from Marah macrocarpus, which encode functionally different GA 3-oxidases that convert C19-GAs to biologically active forms. Increase in stature was observed in plants transformed with AtGA20ox1, MmGA3ox1, MmGA3ox2 and MmGA3ox1 + MmGA3ox2, their presence and expression being confirmed by PCR and RT-PCR, respectively, accompanied by an increase in GA1 content, while PcGA2ox1 resulted in dwarf plant with four fold reduction of height and early flowering. The results are discussed in the context of regulating plant stature. Since this strategy would decrease the use of chemicals to promote plant growth and will result in value addition in ornamental industry, in an era of increasing demand, and ever changing consumer appetite.


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