Ulrich Hammes - Amino acid cycling and post-phloem transport: the long and the short of it

Amino acid transport therefore is critical for nitrogen efficiency with a huge potential to maintain yield quantity and quality with reduced fertilizer input. We identified UmamiTs, a novel, plant-specific family of amino acid transporters, which can transport amino acids bidirectionally across membranes. In the tissues, in which they are expressed, UmamiTs act as the long-sought exporters of amino acids. We were able to demonstrate this role for four UmamiTs that are essential for loading amino acids into the vasculature, unloading them from the vasculature and amino acid supply to seeds and root-knot nematode-induced feeding sites in Arabidopsis.

Karmann, Julia, Müller, Benedikt, and Hammes, Ulrich Z. (2018). The long and winding road: transport pathways for amino acids in Arabidopsis seeds. Plant Reprod. 31, 253-261.

Tegeder, Mechthild, and Hammes, Ulrich Z. (2018). The way out and in: phloem loading and unloading of amino acids. Curr. Opin. Plant Biol. 43, 16-21.

Müller, Benedikt, Fastner, Astrid, Karmann, Julia, Mansch, Verena, Hoffmann, Thomas, Schwab, Wilfried, Suter-Grotemeyer, Marianne, Rentsch, Doris, Truernit, Elisabeth, Ladwig, Friederike, Bleckmann, Andrea, Dresselhaus, Thomas, and Hammes, Ulrich Z. (2015). Amino acid export in developing Arabidopsis seeds depends on UmamiT facilitators. Curr. Biol. 25, 3126-3131.

Ladwig, Friederike, Stahl, Mark, Ludewig, Uwe, Hirner, Axel A., Hammes, Ulrich Z., Stadler, Ruth, Harter, Klaus, and Koch, Wolfgang. (2012). Siliques are red1 from Arabidopsis acts as a bidirectional amino acid transporter that is crucial for the amino acid homeostasis of siliques. Plant Physiol. 158, 1643-1655.

Hoth, Stefan, Stadler, Ruth, Sauer, Norbert, and Hammes, Ulrich Z. (2008). Differential vascularization of nematode-induced feeding sites. Proc. Natl. Acad. Sci. U. S. A. 105, 12617-12622.