Glutamine transport and feedback regulation of nitrate reductase activity in barley roots leads to changes in cytosolic nitrate pools
The size of tissue amino acid pools in plants may indicate nitrogen status and provide a signal that can regulate nitrate uptake and assimilation. The effects of treating barley roots with glutamine have been examined, first to identify the transport system for the uptake of the amino acid and then...
| Veröffentlicht in: | Journal of experimental botany. - 1985. - 57(2006), 6 vom: 15., Seite 1333-40 |
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| 1. Verfasser: | |
| Weitere Verfasser: | , , |
| Format: | Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2006
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| Zugriff auf das übergeordnete Werk: | Journal of experimental botany |
| Schlagworte: | Journal Article Research Support, Non-U.S. Gov't Amino Acid Transport Systems Amino Acids Anion Transport Proteins Nitrate Transporters Nitrates Nitrogen Isotopes Glutamine 0RH81L854J mehr... |
| Zusammenfassung: | The size of tissue amino acid pools in plants may indicate nitrogen status and provide a signal that can regulate nitrate uptake and assimilation. The effects of treating barley roots with glutamine have been examined, first to identify the transport system for the uptake of the amino acid and then to measure root NR activity and cellular pools of nitrate. Treating N replete roots with glutamine elicited a change in the cell membrane potential and the size of this response was concentration dependent. In addition, the size of the electrical change depended on the previous exposures of the root to glutamine and was lost after a few cycles of treatment. Whole root tissue pools of glutamine and phenylalanine increased when roots were incubated in a nutrient solution containing 10 mM nitrate and 1 mM glutamine. Treating roots with 1 mM glutamine increased cytosolic nitrate activity from 3 mM to 7 mM and this change peaked after 2 h of treatment. Parallel measurements of root nitrate reductase activity during treatment with 1 mM glutamine showed a decrease. These measurements provide evidence for feedback regulation on NR activity that result in changes in cytosolic nitrate activity. After 6 h in glutamine both root NR activity and cytosolic nitrate activity returned to pretreatment values, while tissue concentrations of glutamine and phenylalanine remained elevated. The data are discussed in terms of the mechanisms that are most likely to be responsible for the changes in cytosolic nitrate |
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| Beschreibung: | Date Completed 03.08.2006 Date Revised 09.03.2022 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1460-2431 |