Molecular Identification and Physiological Characterization of a Novel Monosaccharide Transporter from Arabidopsis Involved in Vacuolar Sugar Transport
- 1 December 2006
- journal article
- Published by Oxford University Press (OUP) in Plant Cell
- Vol. 18 (12), 3476-3490
- https://doi.org/10.1105/tpc.106.047290
Abstract
The tonoplast monosaccharide transporter (TMT) family comprises three isoforms in Arabidopsis thaliana, and TMT-green fluorescent protein fusion proteins are targeted to the vacuolar membrane. TMT promoter-beta-glucuronidase plants revealed that the TONOPLAST MONOSACCHARIDE TRANSPORTER1 (TMT1) and TMT2 genes exhibit a tissue- and cell type-specific expression pattern, whereas TMT3 is only weakly expressed. TMT1 and TMT2 expression is induced by drought, salt, and cold treatments and by sugar. During cold adaptation, tmt knockout lines accumulated less glucose and fructose compared with wild-type plants, whereas no differences were observed for sucrose. Cold adaptation of wild-type plants substantially promoted glucose uptake into isolated leaf mesophyll vacuoles. Glucose uptake into isolated vacuoles was inhibited by NH(4)(+), fructose, and phlorizin, indicating that transport is energy-dependent and that both glucose and fructose were taken up by the same carrier. Glucose import into vacuoles from two cold-induced tmt1 knockout lines or from triple knockout plants was substantially lower than into corresponding wild-type vacuoles. Monosaccharide feeding into leaf discs revealed the strongest response to sugar in tmt1 knockout lines compared with wild-type plants, suggesting that TMT1 is required for cytosolic glucose homeostasis. Our results indicate that TMT1 is involved in vacuolar monosaccharide transport and plays a major role during stress responses.Keywords
This publication has 58 references indexed in Scilit:
- Identification of a Vacuolar Sucrose Transporter in Barley and Arabidopsis Mesophyll Cells by a Tonoplast Proteomic ApproachPlant Physiology, 2006
- TRANSPORT MECHANISMS FOR ORGANIC FORMS OF CARBON AND NITROGEN BETWEEN SOURCE AND SINKAnnual Review of Plant Biology, 2004
- Engineering tolerance and accumulation of lead and cadmium in transgenic plantsNature Biotechnology, 2003
- Sugar transporters in higher plants – a diversity of roles and complex regulationTrends in Plant Science, 2000
- Sugar transporters in plant biologyCurrent Opinion in Plant Biology, 1999
- Molecular Cloning, Immunochemical Localization to the Vacuole, and Expression in Transgenic Yeast and Tobacco of a Putative Sugar Transporter from Sugar BeetPlant Physiology, 1996
- CLUSTAL W: improving the sensitivity of progressive multiple sequence alignment through sequence weighting, position-specific gap penalties and weight matrix choiceNucleic Acids Research, 1994
- Plant Physiology: Virtue on both sidesCurrent Biology, 1994
- Facilitated Transport of Glucose in Isolated Phloem Segments of CeleryPlant Physiology, 1987
- A Mutant of Synechococcus PCC7942 Incapable of Adapting to Low CO2 ConcentrationPlant Physiology, 1987