The raz1 mutant of Arabidopsis thaliana lacks the activity of a high-affinity amino acid transporter
| Autor: | Michel Jacobs, Adrianus C. Borstlap, M. Van Montagu, Nathalie Verbruggen, Eric Messens |
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| Rok vydání: | 1996 |
| Předmět: |
Amino Acid Transport Systems
Proline biology Mutant Arabidopsis Chromosome Mapping Transporter Plant Science Genes Plant biology.organism_classification chemistry.chemical_compound chemistry Biochemistry Cell culture Mutation Genetics Osmoregulation Amino acid transporter Azetidine-2-carboxylic acid Carrier Proteins Azetidinecarboxylic Acid Plant Proteins |
| Zdroj: | Planta. 200:247-253 |
| ISSN: | 1432-2048 0032-0935 |
| DOI: | 10.1007/bf00208315 |
| Popis: | The raz1 mutant of Arabidopsis thaliana (L.) Heynh. has been selected as resistant to the toxic proline analogue, azetidine-2-carboxylic acid (2AZ). Seedlings of the mutant tolerated fivefold higher concentrations of 2AZ (ED50 = 0.25 mM) than the wild-type seedlings (EC50 = 0.05 mM). The mutant gene was found to be semi-dominant and the corresponding RAZ1 locus was mapped on chromosome 5 at 69.6 +/- 1.8 cM. The resistance to 2AZ could be fully and exclusively accounted for by the lower uptake rate of the proline analogue in the mutant. The influx of L-proline in roots of wild-type seedlings could be dissected into two components: (i) a component with a high affinity and a low capacity for L-proline (Km) approximately 20 microM, Vmax approximately 60 nmol.(g FW)-1.h-1) and also a high affinity for L-2AZ (Ki approximately 40 microM) and (ii) a low-affinity, high-capacity component (Km) approximately 5 mM: Vmax = 1300 nmol.(g FW)-1.h-1). Clearly, the raz1 mutation affects the activity of a high-affinity transporter, because the high-affinity uptake of proline in the mutant was at least fivefold lower than in the wild-type, whereas the low-affinity uptake was unchanged. |
| Databáze: | OpenAIRE |
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