Transgenic ipt tobacco overproducing cytokinins overaccumulates phenolic compounds during in vitro growth.
We present evidence that overproduction of endogenous cytokinins (CK) caused stress response in non-rooting Pssu-ipt transgenic tobacco (Nicotiana tabacum L.) grown in vitro. It was demonstrated by overaccumulation of phenolic compounds, synthesis of pathogenesis related proteins (PR proteins), and increase in peroxidase (POD) activities. Immunolocalization of zeatin and also PR-1b protein on leaf cryo-sections proved their accumulation in all mesophyll cells of transgenic tobacco contrary to control non-transgenic plants. Intensive blue autofluorescence of phenolic compounds induced by UV in cross-sections of leaf midrib showed enhanced contents of phenolics in transgenic tobacco compared with controls, nevertheless, no significant difference between both plant types was found in leaf total lignin content. Transgenic plantlets exhibited higher peroxidase activities of both soluble and ionically bound fractions compared with controls. HPLC analysis of phenolic acids confirmed the increase in all phenolic acids in transgenic tobacco except for salicylic acid (SA). The effect of high phenolic content on rooting of transgenic tobacco is discussed.
Schnablová
Renáta
R
Department of Plant Anatomy and Physiology, Faculty of Sciences, Charles University, Vinicná 5, 128 44 Praha 2, Czech Republic.
Synková
Helena
H
Vicánková
Anna
A
Burketová
Lenka
L
Eder
Josef
J
Cvikrová
Milena
M
D019883:Alkyl and Aryl Transferases / Q000235:genetics* / Q000378:metabolism*; D002478:Cells, Cultured; D003583:Cytokinins / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D010544:Peroxidases / Q000378:metabolism; D010636:Phenols / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000378:metabolism; D018517:Plant Roots / Q000254:growth & development; D030821:Plants, Genetically Modified; D014026:Nicotiana / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*
D003583:Cytokinins; D010636:Phenols; D010937:Plant Growth Regulators; D010544:Peroxidases; D019883:Alkyl and Aryl Transferases; C024274:adenylate isopentenyltransferase