Details

Autor(en) / Beteiligte

• Dobrev, Petre
• Motyka, Václav
• Gaudinová, Alena
• Malbeck, Jiří
• Trávníčková, Alena
• Kamínek, Miroslav
• Vaňková, Radomíra

Titel

Transient accumulation of cis- and trans-zeatin type cytokinins and its relation to cytokinin oxidase activity during cell cycle of synchronized tobacco BY-2 cells

Ist Teil von

• Plant physiology and biochemistry, 2002-04, Vol.40 (4), p.333-337

Ort / Verlag

Paris: Elsevier Masson SAS

Erscheinungsjahr

2002

Quelle

Elsevier Journal Backfiles on ScienceDirect (DFG Nationallizenzen)

Beschreibungen/Notizen

• Changes in levels of endogenous cytokinins and activity of cytokinin oxidase (EC 1.4.3.6) were followed during the cell cycle progression in large-scale (ca. 30 g FW) synchronized culture of the tobacco cell line BY-2. Synchronization was induced either by 4 mM hydroxyurea or 15 μM aphidicolin alone (a single block of the cell cycle at G 1/S) or in combination with 1 μM oryzalin (double blocking at G 1/S and G 2/M). Up to 46% synchrony was obtained. Two distinct cytokinin peaks were detected at 0-2 h and 8.5-9 h after the release from the first block coinciding with the beginning of the S phase and with the onset of mitosis, respectively. Interestingly, as identified by MS/MS, very sharp and transient premitotic peak of cytokinins contained, in addition to trans-zeatin, also considerable amounts of cis-zeatin and zeatin- O-glucoside. Cytokinin oxidase activity exhibited conspicuous maximum parallel to the first peak of cytokinin accumulation and deep minimum corresponding to the culmination of mitotic index. Possible roles of zeatin cis- trans isomerisation, glucosylation and degradation by cytokinin oxidase in regulation of cytokinin levels during the cell cycle progression are discussed.