title: Effects of cor15a-IPT gene expression on leaf senescence in transgenic Petunia x hybrida and Dendranthema x grandiflorum.
abstract: 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 x hybrida 'Marco Polo Odyssey' and Dendranthema x 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 degrees C) after an initial exposure to a brief cold-induction period (4 degrees 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 degrees C.
authors.affiliation: University of Connecticut, Plant Science Department, Agricultural Biotechnology Laboratories, 1390 Storrs Rd, U-4163, Storrs, CT 06269-4163, USA.
authors.forename: Mariya
authors.initials: M
authors.lastname: Khodakovskaya
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.forename: Jisheng
authors.initials: J
authors.lastname: Li
authors.forename: Radomíra
authors.initials: R
authors.lastname: Vanková
authors.forename: Jirí
authors.initials: J
authors.lastname: Malbeck
authors.forename: Richard
authors.initials: R
authors.lastname: McAvoy
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000235:genetics*; D002734:Chlorophyll / Q000378:metabolism; D031202:Chrysanthemum / Q000235:genetics*; D017931:DNA Primers; D018506:Gene Expression Regulation, Plant; D014644:Genetic Variation; D032306:Petunia / Q000201:enzymology / Q000235:genetics*; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D010940:Plant Proteins / Q000235:genetics*; D018520:Plant Shoots / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics; D016133:Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; D010940:Plant Proteins; D002734:Chlorophyll; D019883:Alkyl and Aryl Transferases; C024274:adenylate isopentenyltransferase