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Molecular physiology of the raffinose family oligosaccharides (RFOs) in plants

English title Molecular physiology of the raffinose family oligosaccharides (RFOs) in plants
Applicant Keller Felix
Number 116599
Funding scheme Project funding
Research institution Institut für Pflanzen- und Mikrobiologie Universität Zürich
Institution of higher education University of Zurich - ZH
Main discipline Botany
Start/End 01.11.2007 - 30.11.2011
Approved amount 318'779.00
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Keywords (12)

raffinose oligosaccharides; maltose; carbohydrate metabolism; carbon partitioning; phloem loading; compartmentation; carbon partitioning; maltose; compartmentation; carbohydrate metabolism; phloem loading; raffinose oligosaccharides

Lay Summary (English)

Lead
Lay summary

Carbohydrates are key-players in a multitude of fundamental physiological events in plants, such as development, signaling, carbon transport and storage, cell wall synthesis, and stress protection. We have primarily focused our research on one type of carbohydrate, the water-soluble raffinose family oligosaccharides (RFOs) which are α-1,6 galactosyl extensions of sucrose (Suc) with the most common species being raffinose (Suc-Gal1), stachyose (Suc-Gal2), and verbascose (Suc-Gal3). RFOs are the most abundant oligosaccharides in the plant kingdom and many RFO-producing plants are of economic importance including cucurbits, mints, legumes, olives, grapes, and pines. As primary photosynthetic products RFOs are jacks of all trades, fulfilling diverse physiological functions, such as storage and translocation of carbon and protection against environmental stresses. We have mainly worked with the Lamiaceae, common bugle (Ajuga reptans), because this frost-hardy evergreen is an RFO all-rounder. We have shown that Ajuga utilizes RFOs as the principle form of carbon storage in leaves and roots (up to 80% of the DW) and carbon transport in the phloem (up to 80% of the phloem sugars. After having cloned, characterized, and localized most key-enzymes of the RFO biosynthetic pathway in Ajuga, we will now be focusing our research mainly (i) on the role of RFOs in frost tolerance of Ajuga, comparing it to that of the Brassicaceae, Arabidopsis thaliana (thale cress or mouse-ear cress, a facultative transient RFO accumulator) and (ii) on the pathways of RFO mobilization in source and RFO utilization in sink tissues. To this end, state-of-the-art methods, such as cDNA library construction and screening, biochemical characterization of enzymes using heterologous gene expression systems, stable plant transformation, in situ enzyme activity staining, in situ hybridization, confocal microscopy, immunolocalization, HPLC carbohydrate analysis etc. will be applied. Collectively, the proposed research will illuminate how RFOs are involved in conferring stress tolerance and how the organization of the RFO catabolic pathway facilitates proper growth. Both processes are of fundamental importance and still poorly understood.


Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

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Publications

Publication
Frost tolerance in excised leaves of the common bugle (
Peters Shaun, Keller Felix, Frost tolerance in excised leaves of the common bugle (, in Plant Cell and Environment, 32, 1099-1107.
Functional identification of Arabidopsis AtSIP2 (At3g57520) as an alkaline α-galactosidase with a substrate specificity for raffinose and an apparent sink-specific expression pattern
Peters Shaun, Egert Aurélie, Stieger Bruno, Keller Felix, Functional identification of Arabidopsis AtSIP2 (At3g57520) as an alkaline α-galactosidase with a substrate specificity for raffinose and an apparent sink-specific expression pattern, in Plant and Cell Physiology, 51, 1815-1819.
Phloem loading, plant growth form, and climate
Davidson Anna, Keller Felix, Turgeon Robert, Phloem loading, plant growth form, and climate, in Protoplasma, 248, 153-163.
Protection mechanisms in the resurrection plant
Lehner A., Chopera D. R., Peters S. W., Keller F., Mundree S. G., Thomson J. A., Farrant J. M., Protection mechanisms in the resurrection plant, in Functional Plant Biology, 35, 26-39.
Quantitative detection of changes in the leaf-mesophyll tonoplast proteome in dependency of a cadmium exposure of barley (Hordeum vulgare L.) plants
Schneider T., Schellenberg M., Meyer S., Keller F., Gehrig P., Riedel K., Lee Y., Eberl L., Martinoia E., Quantitative detection of changes in the leaf-mesophyll tonoplast proteome in dependency of a cadmium exposure of barley (Hordeum vulgare L.) plants, in Proteomics, 9, 2668-77.
Raffinose in chloroplasts is synthesized in the cytosol and transported across the chloroplast envelope
Schneider Thomas, Keller Felix, Raffinose in chloroplasts is synthesized in the cytosol and transported across the chloroplast envelope, in Plant Cell Physiology, 50, 2174-2182.

Associated projects

Number Title Start Funding scheme
103681 Molecular physiology of the raffinose family oligosaccharides (RFOs) in plants 01.04.2004 Project funding

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