Subcellular localization of maize cytokinin dehydrogenases – Bc. Patricie JOHNOVÁ
Bc. Patricie JOHNOVÁ
Master's thesis
Subcellular localization of maize cytokinin dehydrogenases
Subcellular localization of maize cytokinin dehydrogenases
Abstract:
Cytokinindehydrogenasy (CKX; EC 1.5.99.12) patří do významné třídy enzymů, které zprostředkovávají irreversibilní degradaci rostlinných hormonů cytokininů a přispívají tak k udržování jejich rovnováhy. V mnoha rostlinných druzích byly nalezeny malé genové rodiny CKX. Jedním z jedinečných aspektů CKX je jejich odlišná subcelulární lokalizace, která zřejmě úzce souvisí s jejich odlišnou substrátovou …moreKeywords
Cytokinin dehydrogenases (CKX EC 1.5.99.12) belong to the important class of enzymes mediating irreversible degradation of plant hormones cytokinins and thus contribute to the maintainance of cytokinin homestasis. Presence of small CKX gene families have been reported in many plant species. One of the unique aspects of CKX isozymes is their diverse subcellular localization which is also assumed to be responsible for preferences of CKX to various substrates. So far best characterized is AtCKX gene family from dicotyledonous plant model Arabidopsis thaliana comprising seven members. Overexpression of AtCKX genes proved that distinct subcellular localization along with the distinct temporal distribution of CKX have strong impact on plant phenotype as a result of cytokinin-deficient syndrome. The maize genome encompasses thirteen ZmCKX members whose biochemical properties as well as tissue expression patterns were described in detail only recently. However the information on the CKX subcellular localization in monocots is still not clear. Previously only two isoforms has been studied in detail ZmCKX1 which was shown to be secreted to apoplastic space and ZmCKX10 indicating dual expression pattern partially in cytosol and nucleus.The goal of the present study was to disclose subcellular distribution of ten ZmCKX isozymes. Individual ZmCKX (1 2 4a 4b 5 6 8 9 10 and 12) genes were tagged to green fluorescent protein (GFP) and their expression pattern was examined using live cell confocal microscopy. Transient expression of Ubi1 ZmCKX-GFP in maize protoplasts revealed the majority of ZmCKX isoforms is associated with endoplasmic reticulum (ER). In order to confirm these results stable cell lines of Arabidopsis expressing CaMV35S ZmCKX-GFP were established. Surprisingly almost all ZmCKXs were primarily targeted to vacuoles. These results refer to the possibility that ER-localization is a transition point to vacuoles which seems to be the final destination of most of the ZmCKX isozymes. In addition the localization of apoplastic isoform ZmCKX1 and cytosolic/nuclear ZmCKX10 was proved in both assays. This study provided the first insight into the spatial distribution of cytokinin catabolism in monocotyledonous species.
Language used: English
Date on which the thesis was submitted / produced: 30. 4. 2015
Accessible from:: 30. 4. 2015
Thesis defence
- Date of defence: 25. 5. 2015
- Supervisor: Mgr. David Zalabák, Ph.D.
Citation record
The right form of listing the thesis as a source quoted
JOHNOVÁ, Patricie. Subcellular localization of maize cytokinin dehydrogenases. Olomouc, 2015. diplomová práce (Mgr.). UNIVERZITA PALACKÉHO V OLOMOUCI. Přírodovědecká fakulta
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Institution archiving the thesis and making it accessible: UNIVERZITA PALACKÉHO V OLOMOUCI, Přírodovědecká fakultaPALACKÝ UNIVERSITY OLOMOUC
Faculty of ScienceMaster programme / field:
Biochemistry / Biochemistry
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