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Monitoring the role of distinct sugars on cell division in Arabidopsis plant cells and seedlings
Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Within the last decades, research on sugar-dependent plant growth provided evidence for a directregulation of cell division by sugars. Recently we showed, in A. thaliana cell suspension cultures, thatdistinct sugars differentially regulate a rapid transcriptional response of genes, some of which functionduring the cell cycle progression. In order to assess the relationship between sugar species and celldivision, we developed a new methodology for long-term real-time live-cell imaging on dividing A.thaliana cell suspension cultures. This technique, using cells grown in hormone-free media, allowed toestimate the cell cycle synchronicity and efficiency of an entire cell population and to monitor thedynamics and geometry of cell division in single cells in response to a given sugars. A marker cell lineconstitutively expressing TUA::GFP, a protein that labels microtubule-based structures hallmarkingprogression of the mitotic division, was used to measure the sugar-dependent efficiency andsynchronicity of the cell cycle progression. Altogether, we were able to confirm the distinct relationshipsof specific sugar molecules on the cell cycle progression at a single cell level. Cell division efficiencyand synchronicity were altered when grown on the different sugars sucrose, glucose and xylose.Interestingly, the progression of the mitotic division appeared unaffected by the sugar species supplied,indicating that length of the interphase is likely to control the cell division rate. In contrast, treatment ofA. thaliana cell cultures and seedlings with the Glc-analogue 2-deoxy-glucose (2dog) led to growtharrest and to cell death during long exposure. The growth resulting from 2dog removal in cell culturesand seedlings showed the unique feature of plants to induce new active zones of cell division.

Keyword [en]
Cell suspension culture, cell division, long-term real-time live cell imaging, sugar regulation of gene expression and cellular processes
National Category
Cell Biology Botany Biochemistry and Molecular Biology
Research subject
Physiological Botany; cellforskning
URN: urn:nbn:se:umu:diva-96579OAI: diva2:765457
Available from: 2014-11-24 Created: 2014-11-24 Last updated: 2014-11-25Bibliographically approved
In thesis
1. Sugar-modulated gene expression and cell division in cell culture and seedlings of A. thaliana
Open this publication in new window or tab >>Sugar-modulated gene expression and cell division in cell culture and seedlings of A. thaliana
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Throughout their life cycle, plants adjust growth in response to their developmental and environmental situation within the limits of their energetic capacities. This capacity is defined by the local sugar availability, which is constantly modulated through synthesis, transport and consumption of sugar. The monitoring of sugar presence is carried out by a complex signalling network in which simple sugars (e.g. glucose, fructose and sucrose) act as metabolic signals for the modulation of physiological processes. However, often it remains unclear whether the regulation is induced by the simple sugars themselves or by their derivatives generated during sugar metabolism. This thesis focuses on the dissection of distinct sugar signals, their generation, perception and impact on the modulation of gene expression and cell division both in cell culture and young seedlings.

Based on a stem-cell-like A. thaliana cell culture, which could be sustained in a hormone-free media, a new biological system, supplied with Xyl as the only carbon source was developed. The performance of a variety of sugar and sugar analogue treatments in this novel system allowed for the identification of sugar-responsive candidate genes, which were specifically regulated by glucose, fructose and sucrose. For several genes (e.g. bZIP63, AT5g22920, TPS9, MGD2 and BT2), this regulation required both sugar transport into the cytosol and metabolisation for the generation of the signal. Furthermore, gene expression analyses in young A. thaliana seedlings indicated the requirement for the catalytic activity of hexokinase 1 in the regulation of bZIP63, Atg22920 and BT2 under conditions of a perturbed carbohydrate balance. These findings have been combined in a proposed model for the transcriptional regulation of bZIP63, AT5g22920, TPS9, MGD2 and BT2, which further proposes a function of those genes in the regulation of cell division.

The optimisation of a protocol for long-term real-time live-cell imaging provided a valuable tool to show that, similar to gene expression, the progression of cell division depended on a sugar-type-specific regulation at the single-cell level; this regulation was most likely caused by prolongation of the interphase. Together with the observation of cell death and growth arrest of the primary root in intact seedlings in response to the glucose analogue 2dog, this led to the conclusion that sugar signals themselves were sufficient to induce cell division. However, the continuation of cell cycle progression and consequently organ growth over long-time required the availability of the energy contained in the sugar.

Place, publisher, year, edition, pages
Umeå: Umeå University, 2014. 59 p.
Arabidopsis thaliana, carbohydrates, cell culture, cell division, gene expression, homeostasis, live cell imaging, sugar-signals, sugar-analogues
National Category
Biochemistry and Molecular Biology Botany Cell Biology
Research subject
Physiological Botany
urn:nbn:se:umu:diva-96580 (URN)978-91-7601-174-4 (ISBN)
Public defence
2014-12-17, KB3A9; KBC huset, Umeå universitet, Umeå, 10:00 (English)
Available from: 2014-11-26 Created: 2014-11-24 Last updated: 2015-04-29Bibliographically approved

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Kunz, Sabine
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