1. The Arabidopsis thaliana ABC transporter AtMRP5 controls root development and stomata movement.
- Author
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Gaedeke N, Klein M, Kolukisaoglu U, Forestier C, Müller A, Ansorge M, Becker D, Mamnun Y, Kuchler K, Schulz B, Mueller-Roeber B, and Martinoia E
- Subjects
- ATP-Binding Cassette Transporters classification, Amino Acid Sequence, Anions metabolism, Glyburide pharmacology, Indoleacetic Acids analysis, Molecular Sequence Data, Mutation, Plant Leaves cytology, Plant Proteins classification, Plant Proteins genetics, Sequence Homology, Amino Acid, Tissue Distribution, ATP-Binding Cassette Transporters genetics, Arabidopsis physiology, Arabidopsis Proteins, Multidrug Resistance-Associated Proteins, Plant Leaves physiology, Plant Roots growth & development
- Abstract
In the present study, we investigated a new member of the ABC transporter superfamily of Arabidopsis thaliana, AtMRP5. AtMRP5 encodes a 167 kDa protein and exhibits low glutathione conjugate and glucuronide conjugate transport activity. Promotor- beta-glucuronidase fusion constructs showed that AtMRP5 is expressed mainly in the vascular bundle and in the epidermis, especially guard cells. Using reverse genetics, we identified a plant with a T-DNA insertion in AtMRP5 (mrp5-1). mrp5-1 exhibited decreased root growth and increased lateral root formation. Auxin levels in the roots of mrp5-1 plants were increased. This observation may indicate that AtMRP5 works as an auxin conjugate transporter or that mutant plants are affected in ion uptake, which may lead to changes in auxin concentrations. Experiments on epidermal strips showed that in contrast to wild type, the sulfonylurea glibenclamide had no effect on stomatal opening in mrp5-1 plants. This result strongly suggests that AtMRP5 may also function as an ion channel regulator.
- Published
- 2001
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