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ARS Home » Research » Publications at this Location » Publication #123774
Title: NITRATE, SUGAR, AND LIGHT REGULATION OF AMINO ACID TRNSPORTER EXPRESSION

Author
item GUO, MENGJUAN - PLANT BIOLOGY UOFI URBANA
item BUSH, DANIEL

Submitted to: Arabidopsis Research International Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 7/25/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: In higher plants, amino acids are the currency of nitrogen exchange between sites of primary assimilation and import-dependent tissues. The partitioning of amino acids in this resource allocation process requires the activity of several amino acid transporters in the plasma membrane. In the results reported here, we show that the expression level of one of these transporters is regulated as a function of nutrient status and environmental cues. The transcript of AAP1, a proton-amino acid symporter, in mature leaf tissue is induced by both nitrogen and carbon sources. AAP1 message is highly induced in nitrogen depleted plants after feeding KNO3 for 30 min. AAP1 is also induced in dark-adapted plants after 3 hours of illumination. Light dependent changes in expression may be mediated by a specific photoreceptor or by photosynthesis-dependent increases in leaf sugar content. We show that both sucrose or glucose feeding induces AAP1 message in dark- adapted plants, suggesting light induction is an indirect effect of sugar-signaling. However, we can not rule out a role for a photoreceptor and therefore, we are exploring this question directly with defined light treatments and non-responsive mutants. These results demonstrate that AAP1 expression is regulated by key metabolites that tie its expression to the global distribution of organic nutrients.