Tan, Qiumin , Grennan, Aleel , Rentsch, Doris , Tegeder, Mechthild .
Identification and characterization of amino acid transporters in legume seeds.
Transport of amino acids to seeds mainly occurs via the phloem, and phloem unloading of reduced nitrogen into the seed coat is via plasmodesmata. Due to the symplasmic discontinuity between the seed coat and the cotyledons, amino acids are then released into the apoplast, and taken up by the cotyledons for development and storage proteins synthesis. The uptake of amino acids involves transport proteins located in the outer epidermis of legume cotyledons, especially at later stages of seed development when large amounts of storage proteins are synthesized and sufficient supply is required. To gain further insights into amino acid transport processes in legume seeds, yeast expression cDNA libraries were constructed from pea (Pisum sativum L.) and French bean (Phaseolus vulgaris L.) cotyledons and expressed in yeast mutants deficient in specific amino acid transport systems. Functional complementation resulted in the isolation of one bean (PvAAP3) and two pea (PsAAP4 and PsAAP5) amino acid permeases. In addition, one member of the cationic amino acid transporter family (CAT) was isolated from pea cotyledons (PsCAT6) by homologous cloning. Function of the newly isolated amino acid transporters could be shown by complementation in yeast mutants. RT-PCR was used to study the organ expression pattern of the transporters. Furthermore, cellular or subcellular localization of the transporters were investigated by in situ RNA hybridization or localization of GFP-transporter fusion proteins, respectively.
This work is funded by the National Science Foundation (grant IBN 0448506).
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1 - Washington State University, School of Biological Sciences, Pullman, WA, 99163, USA
2 - University of Illinois, Photosynthesis Research Unit, USDA/ARS
3 - University of Bern, Institute of Plant Sciences
4 - washington state university, School of Biological sciences
amino acid transport
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM