Journal Article

Effects of cor15a-IPT gene expression on leaf senescence in transgenic Petunia×hybrida and Dendranthema×grandiflorum

Mariya Khodakovskaya, Yi Li, Jisheng Li, Radomíra Vaňková, Jiří Malbeck and Richard McAvoy

in Journal of Experimental Botany

Published on behalf of Society for Experimental Biology

Volume 56, issue 414, pages 1165-1175
Published in print April 2005 | ISSN: 0022-0957
Published online February 2005 | e-ISSN: 1460-2431 | DOI: https://dx.doi.org/10.1093/jxb/eri109

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To prevent leaf senescence of young transplants or excised shoots during storage under dark and cold conditions, the cytokinin biosynthetic gene isopentenyl transferase (ipt) was placed under the control of a cold-inducible promoter cor15a from Arabidopsis thaliana and introduced into Petunia×hybrida ‘Marco Polo Odyssey’ and Dendranthema×grandiflorum (chrysanthemum) ‘Iridon’. Transgenic cor15a-ipt petunia and chrysanthemum plants and excised leaves remained green and healthy during prolonged dark storage (4 weeks at 25 °C) after an initial exposure to a brief cold-induction period (4 °C for 72 h). However, cor15a-ipt chrysanthemum plants and excised leaves that were not exposed to a cold-induction period, senesced under the same dark storage conditions. Regardless of cold-induction treatment, leaves and plants of non-transformed plants senesced under prolonged dark storage. Analysis of ipt expression indicated a marked increase in gene expression in intact transgenic plants as well as in isolated transgenic leaves exposed to a short cold-induction treatment prior to dark storage. These changes correlated with elevated concentrations of cytokinins in transgenic leaves after cold treatment. Cor15a-ipt transgenic plants showed a normal phenotype when grown at 25 °C.

Keywords: Cold-inducible promoter; cytokinins; ipt expression; leaf senescence; ornamental plants

Journal Article.  7601 words.  Illustrated.

Subjects: Plant Sciences and Forestry

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