| Abstract Detail
Hormone Biology Zubo, Yan [1], Yamburenko, Maria [1], Selivankina, Svetlana [1], Shakirova, Farida [4], Avalbaev, Azamat [4], Kudryakova, Natalia [1], Zubkova, Natalia [1], Liere, Karlsten [8], Kusnetsov, Victor [1], Boerner, Thomas [8], Kulaeva, Olga [10]. Cytokinins regulate chloroplast gene transcription in detached barley leaves. It is shown for the first time that cytokinins are involved in the control of individual chloroplast gene transcription. The experiments were performed on the first barley leaves detached from 9-day-old plants. The leaves were incubated on water in the light (270 µmol/(m2 s) for 24 h; then they were transferred to the 6-benzyladenine (BA, 2.2 x 10-5M) solution for 3 h. Chloroplasts were isolated from the apical 2-cm leaf segments; they were used for run-on transcription. In vitro synthesized radioactive transcripts were hybridized with probes specific for 36 genes representing all functional groups of plastid genes. It was established that cytokinins regulated differentially 13 of 36 chloroplast genes. We demonstrated a complex interaction between the cytokinin control of chloroplast gene transcription and the regime of leaf illumination. All genes tested could be divided into the two groups after their response to illumination. For transcription activation of the rpl16, matK, trnEY, petLG, petD and rps14 genes, light was required during both leaf pre-incubation on water and incubation with BA. For the rbcL, rrn16, atpB, rps16, rps4, ndhC and rrn23 genes, light was required only during leaf pre-incubation on water, whereas cytokinin could exert its action in darkness as well. It was shown that detached leaf pre-incubation on water in the light for 24 h resulted in a sharp accumulation of ABA in them. Cytokinin regulation of chloroplast gene transcription depended on the leaf age and the leaf-blade zone. A dependence of chloroplast transcription sensitivity to cytokinin on the tissue age was also manifested in the shift of the cytokinin-responsive zone in the old first leaf of 22-day-old seedlings from the upper leaf part, which became too old, to the middle zone.
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1 - Timiriazev Institute of Plant Physiology, Russian Academy of Sciences,, Plant genome expression
2 - Timiriazev Institute of Plant Physiology, Russian Academy of Sciences,, Plant genome expression
3 - Timiriazev Institute of Plant Physiology, Russian Academy of Sciences,, Plant genome expression
4 - Institute of Biochemistry and Genetics, Ufa Research Center, Russian A
5 - Institute of Biochemistry and Genetics, Ufa Research Center, Russian A
6 - Timiriazev Institute of Plant Physiology, Russian Academy of Sciences,, Plant genome expression
7 - Timiriazev Institute of Plant Physiology, Russian Academy of Sciences,, Plant genome expression
8 - Humboldt University, Chausseestrasse 117, D-10115, Berlin, Germany, Institute of Biology
9 - Timiriazev Institute of Plant Physiology, Russian Academy of Sciences,, Plant genome expression
10 - Timiriazev Institute of Plant Physiology, Russian Academy of Sciences,, Plant genome expression, Botanicheskaya 35, Moscow, Russia, 127276, Russia
Keywords:
Cytokinin
chloroplast transcription.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P35036
Abstract ID:1368 |
