American Society of Plant Biologists 
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Poster: Membrane Transport

Abs # P10011: Transporters for di- and tripeptides in Arabidopsis

Presenter: Brinkmann, Christopher       Contact Presenter
AuthorsBrinkmann, Christopher  (A)   Komarova, Nataliya  (A)   Thor, Kathrin  (A)   Suter-Grotemeyer, Marianne  (A)   Rentsch, Doris  (A)   Dietrich, Daniela  (B)  
Affiliations: (A): University of Bern, Institute of Plant Sciences
(B): University of Nottingham, Division of Agricultural and Environmental Sciences
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For the efficient redistribution of organic nitrogen in plants, small peptides are proposed as an important alternative to amino acids. Transporters for di- and tripeptides have been identified belonging to the PTR (peptide transporter) family, a large family with over 50 members in Arabidopsis that also comprises low-affinity nitrate transporters and a large number of non-characterized transporter proteins. <br />In this study we focus on five highly homologous AtPTR genes. Using heterologous expression systems, we could demonstrate that at least three AtPTRs are able to transport di- and tripeptides. Expression of the GUS reporter gene under the control of the different AtPTR promoters showed distinct expression patterns. Furthermore, AtPTR/GFP fusion proteins were localized at the plasma membrane or at the tonoplast when transiently expressed in protoplasts. The results suggest that the AtPTRs play specific roles in intracellular and long-distance transport of small peptides, in uptake of peptides from the soil and in nitrogen redistribution during seed loading, germination and senescence. To further assess their physiological function, T-DNA insertion lines and lines overexpressing AtPTRs are currently being analyzed.

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