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Washington State University Molecular Plant Sciences

Mechthild Tegeder

Professor of Biological Sciences
Ph.D., University of Göttingen, Germany


The development of strategies to improve crop productivity to meet growing societal needs for food supply and alternative sources of energy provides a challenge to current and future research on plants. In addition, the balanced intake of essential nutrients or metabolites is important for human nutrition worldwide, but sub-optimal content often occurs in crop species, as for example the case for the essential amino acid methionine in legume seeds. Nitrogen (N) is an important nutrient that plants require in large amounts for growth and development. N is needed for the synthesis of many crucial compounds, such as amino acids, proteins, chlorophyll and specialized metabolites, and it is fundamental for physiological processes including photosynthesis and plant defense. In agricultural systems, high N fertilization guarantees maximum crop yields. However, intensive fertilizer production and application are unsustainable because of high-energy requirements and environmental damage due to N pollution.

Within plants, N partitioning and long-distance transport mainly occurs in the forms of amino acids and ureides. The distribution of the organic N from the location of synthesis (sources e.g. root, nodules or leaves) to sites of utilization (sinks e.g. developing leaves, tubers and seeds) is a major factor influencing plant growth and seed development. It requires the function of transport proteins localized in cellular membranes of the N exporting and importing plant organs. Our program has been at the forefront of research on source-to-sink transport of amino acids and ureides. Major breakthroughs on transporter function have been achieved by using transporter repression or overexpression approaches in the model system Arabidopsis and in legumes (i.e. pea, Pisum sativum and soybean, Glycine max), and complex biochemical, physiological, genetic, molecular and cell-biological analyses of the transgenic plants.

Please see also:


Publications since 2016

Perchlik M. and Tegeder M. (2018) AAP2 amino acid transporter function in photosynthetic and plant nitrogen use efficiency in Arabidopsis. Plant Physiology. In press. DOI:

Garneau M.G., Tan Q. and Tegeder M. (2018). Amino acid permease AAP6 is essential for nitrogen export from pea nodules, but does not control nitrogen fixation. Journal of Experimental Botany. In press. DOI:

Tegeder M. and Masclaux-Daubresse C. (2018) Source and sink mechanisms of nitrogen transport and use. Tansley Review. New Phytologist 217: 5-53. doi: 10.1111/nph.14876

Tegeder M. and Hammes U. (2018) The way out and in: phloem loading and unloading of amino acids. Current Opinion in Plant Biology 43: 16–21. doi: 10.1016/j.pbi.2017.12.002

Perchlik M. and Tegeder M. (2017) Improving plant nitrogen use efficiency through alteration of amino acid transport processes. Plant Physiology, 175: 235-247. doi: 10.1104/pp.17.00608. Recommended by F1000

Santiago J.P. and Tegeder M. (2017) Implications of nitrogen phloem loading for carbon metabolism and transport during Arabidopsis development. Journal of Integrated Plant Biology 59, 409–421; doi: 10.1111/jipb.12533.

Carter A. and Tegeder M. (2016) Increasing nitrogen fixation and seed yield in soybean requires complex adjustments of nodule nitrogen metabolism and partitioning processes; Current Biology 26, 1-8. Highly recommended by F1000

Santiago J.P. and Tegeder M. (2016) Connecting source with sink: the role of Arabidopsis AAP8 in phloem loading of amino acids. Plant Physiology 171, 508-521. Highly Recommended by F1000

Publications 2015-2010

Zhang L., Garneau M.G. Majumdar R., Grant J. and Tegeder M. (2015) Improvement of pea biomass and seed productivity by simultaneous increase of phloem and embryo loading with amino acids. The Plant Journal 81, 134–146. Recommended by F1000

Perchlik M., Foster J. and Tegeder M. (2014) Different and overlapping functions of Arabidopsis LHT6 and AAP1 transporters in root amino acid uptake. Journal of Experimental Botany, 65, 5193-5204.

Tegeder M. (2014) Transporters involved in source to sink partitioning of amino acids and ureides: opportunities for crop improvement. Journal of Experimental Botany 65, 1865-1878.

Collier R. and Tegeder M. (2012) Soybean ureide transporters play a critical role in nodule development, function and nitrogen export. The Plant Journal 72, 355-367, COVER ILLUSTRATION. Recommended by F1000

Tegeder M. (2012) Transporters for amino acids in plant cells: some functions and many unknowns. Current Opinion in Plant Biology 15:315–321

Tegeder M. and Ward J.M. (2012) Molecular evolution of plant AAP and LHT amino acid transporters, Frontiers in Plant Physiology 3, 1-11, doi: 10.3389/fpls.2012.00021

Zhang L., Tan Q., Lee R., Trethewy A., Lee Y.-H. and Tegeder M. (2010) Altered amino acids transported by AAP2 changes seed yield and oil content in Arabidopsis. Plant Cell 22, 3603-3620. Recommended by F1000

Tan Q., Zhang L., Grant J., Cooper P. and Tegeder M. (2010) Altered phloem transport of S-methylmethionine affects plant metabolism and seed number in pea plants. Plant Physiology 154, 1886-1896.

Tegeder M. and Rentsch D. (2010) Uptake and Partitioning of Amino Acids and Peptides. Molecular Plant 3, 997-1011.

Sanders, A., R. Collier, A. Trethewy, G. Gould, R. Sieker and Tegeder M. (2009) AAP1 regulates import of amino acids into developing Arabidopsis embryos. The Plant Journal 59, 540–552.

Publications before 2010

Telang M.A., Giri A.P., Pyati P.S., Gupta V.S., Tegeder M. and Franceschi V.R. (2009) Winged bean chymotrypsin inhibitors retard growth of Helicoverpla anmigera. Gene 431, 80-85.

Komarova N.Y., Thor K., Gubler A., Meier S., Dietrich D., Weichert A., Suter Grotemeyer M., Tegeder M., and Rentsch D. (2008) AtPTR1 and AtPTR5 transport dipeptides in planta. Plant Physiology 148, 856-869.

Foster J., Lee Y.H. and Tegeder M. (2008) Distinct expression of members of the LHT amino acid transporter family in flowers indicates specific roles in plant reproduction. Sexual Plant Reproduction 21, 143-152.

Tan Q., Grennan A., Rentsch D. and Tegeder M. (2008) Isolation and characterization of an amino acid transporter from French bean (Phaseolus vulgaris L.). Plant Science 174, 348-356.

Tegeder M., Tan Q., Grennan A. and Patrick J.W. (2007) Amino acid transporter expression and localisation studies in pea (Pisum sativum L.). Functional Plant Biology 34, 1019-1028 (month’s feature paper).

Rentsch D., Schmidt S. and Tegeder M. (2007). Transporters for uptake and allocation of organic nitrogen compounds in plants. FEBS Letters 581, 2281-2289.

Lee Y.H., Foster J., Chen J., Voll L.M., Weber A.P.M. and Tegeder M. (2007). AAP1 transports uncharged amino acids into roots of Arabidopsis. The Plant Journal 50, 305-319.

Pélissier H.C. and Tegeder M. (2007) PvUPS1 plays a role in source-sink transport of allantoin in French bean (Phaseolus vulgaris). Functional Plant Biology 34, 282-291.

Lee Y.-H. and Tegeder M. (2004) Selective expression of a novel high affinity transport system for acidic and neutral amino acids in the tapetum cells of Arabidopsis flowers. The Plant Journal 40, 60-74. COVER ILLUSTRATION.

Okumoto S., Koch W., Tegeder M. Fischer W.N., Biehl A., Leister D., Stierhof Y. and Frommer W.B. (2004) Root phloem-specific expression of the plasma membrane amino acid proton co-transporter AAP3. Journal of Experimental Botany 55: 2155-2168.

Pelissier H. C., Frerich A., Desimone M., Schumacher M., and Tegeder M. (2004) PvUPS1, an allantoin transporter in nodulated roots of French bean. Plant Physiology 134, 664-675.

Koch W., Kwart M., Laubner M. , Heineke D., Stransky H., Frommer W.B. and Tegeder M. (2003) Reduced amino acid content in transgenic potato tubers due to antisense inhibition of the leaf H+/amino acid symporter StAAP1. The Plant Journal 33, 211-220. Recommended by F1000

Wipf D. , Benjdia M., Rikirsch E., Zimmermann S., Tegeder M., and Frommer W.B.  (2003) A Hebeloma cylindrosporum expression cDNA library for suppression cloning in yeast mutants, complementation of a yeast his4 mutant and EST analysis. Genome 46, 177-81.

Lalonde S., Tegeder M., Thorne-Holst M., Frommer W.B. and Patrick J.W. (2003) Phloem loading and unloading of sugars and amino acids. Plant Cell Environment 26, 37-56.

Okumoto S., Schmidt R., Tegeder M., Fischer W.N., Rentsch D, Frommer W.B., Koch W.  (2002) High affinity amino acid transporters specifically expressed in xylem parenchyma and developing seeds of Arabidopsis. Journal Biological Chemistry 277, 45338-45346.

Wipf D., Ludewig U., Tegeder M., Rentsch D., Koch W. and Frommer W.B. (2002) Amino acid/neurotransmitter transporters are highly conserved between fungi, plants, and animals. Trends Biochem Sci 27, 139-47.

Wipf D., Benjdia M., Tegeder M.  and Frommer W.B.  (2002). Characterization of a general amino acid permease from Hebeloma cylindrosporum by functional complementation of a yeast mutant. FEBS Letters 528, 119-124.

Fischer W.N., Loo D.D.F., Koch W., Ludewig U., Boorer K.J., Tegeder M., Rentsch D., Wright E.M. and Frommer W.B. (2002) Low and high affinity amino acid H+-cotransporters for cellular import of neutral and charged amino acids. The Plant Journal 29, 717-31.

Desimone M., Catoni E., Ludewig U., Hilpert M., Schneider A., Kunze R., Tegeder M., Frommer W.B. and Schumacher K. (2002) A novel superfamily of transporters for allantoin and other oxo-derivatives of N heterocyclic compounds in Arabidopsis. Plant Cell 14, 847-56.

Rosche E., Blackmore D., Tegeder M., Richardson T., Schroeder H., Higgins T.J.V., Frommer W.B., Offler C.E. and Patrick J.W. (2002) Seed-specific overexpression of a potato sucrose transporter increases sucrose uptake and growth rates of developing pea cotyledons. The Plant Journal 30 (2), 165-175.

Delrot S., Rochat C., Tegeder M. and Frommer W.B. (2001). Amino acid transport. In: Plant Nitrogen, (Eds) P Lea and JF Morot Gaudry, INRA-Springer, ISBN 3-540-67799-2, pp 213-235.

Tegeder M., Offler C.E., Frommer W.B. and Patrick J.W. (2000) Amino acid transporters are localized to transfer cells of developing pea seeds. Plant Physiology 122, 319-326.

Tegeder M., Thomas M., Hetherington L., Wang X.-D., Offler C.E. and Patrick J.W. (2000) Genotypic differences in seed growth rates of Phaseolus vulgaris L. Factors contributing to cotyledon sink activity and sink size. Aust J Plant Physiol 27, 119-29.

Tegeder M., Wang X.-D, Frommer W.B, Offler C.E, and Patrick J.W. (1999). Sucrose transport into developing seeds of Pisum sativum L. The Plant Journal 18, 151-61.

Montamat F., Tegeder M., Frommer W.B. and Delrot S. (1999) Cloning and expression of a pod-specific amino acid transporter from broad bean. Plant Molecular Biology 41, 259-268.

Fischer W.-N., André B.A., Rentsch D., Krolkiewicz S., Tegeder M., Breitkreuz K. and Frommer W.B. (1998). Amino acid transport in plants. Trends Biochem Sci 3, 188-95.

Harrington G.N., Franceschi V.R., Offler C.E., Patrick J.W., Tegeder M., Frommer W.B., Harper J.F. and Hitz W.D. (1997). Cell specific expression of three genes involved in plasma membrane sucrose transport in developing Vicia faba seed. Protoplasma 197, 160-173.

Harrington G.N., Nussbaumer Y., Wang X.-D. Tegeder M., Offler C.E, Patrick J.W., Franceschi V.R. and Frommer W.B. (1997). Temporal and spatial expression of plasma membrane sucrose transport-related genes in cotyledons of Vicia faba L. Protoplasma 200, 35-50.

Ward J.M., Kühn C., Tegeder M., and Frommer W.B. (1997). Sucrose transport in plants. International Review of Cytology 178, 41-71.

Zenkteler M., Tegeder M., and Schieder O. (1998). Embryological studies of reciprocal crosses between Vicia faba and Vicia narbonensis. Acta Soc Bot Pol 67, 37-43.

Tegeder M., Kohn H., Nibbe M., Schieder O. and Pickardt T. (1996). Plant regeneration from protoplasts of Vicia narbonensis via somatic embryogenesis and shoot organogenesis. Plant Cell Reports 16, 22-25.

Tegeder M., Schieder O. and Pickardt T. (1995). Breakthrough in the plant regeneration from protoplasts of Vicia faba and V. narbonensis. Current Issues in Plant and Cellullar Biology. Kluwer, London, pp 75-80.

Tegeder M., Gebhardt D., Schieder O. and Pickardt T. (1995). Thidiazuron-induced plant regeneration from protoplasts of Vicia faba cv. Mythos. Plant Cell Reports 15, 164-169.

Pickardt T., Schieder O., Saalbach I., Tegeder M., Machemahl F., Saalbach G., Kohn H. and Muentz K. (1994). Regeneration and transformation in the legume Vicia narbonensis. In: Oono K. (ed.). Plant Tissue and Gene Manipulation for Breeding and Formation of Phytochemicals. NIAR, Japan, pp 89-94.

Books and Book Chapters

Tegeder M. and Perchlik M. (2018) The importance of organic nitrogen transport processes for plant productivity and nitrogen use efficiency. In Shrawat A.K. Zayed A. and Lightfoot D.A., eds, Engineering Nitrogen Utilization in Crop Plants, Springer New York; pp 233-253.

Tegeder M., Ruan Y.-L. and Patrick J.W. (2013) Roles of membrane transporters in phloem functions; in Thompson G. and van Bel A., eds, Biochemistry of Phloem, Wiley-Blackwell, Oxford, pp 63-101.

Tegeder M., Rentsch D. and Patrick J.W. (2011) Organic carbon and nitrogen transporters. In Murphy A., Peer W. and Schulz B., eds, Plant Plasma Membrane. Plant Cell Monographs, Springer, Berlin, pp 331-352.

Tegeder M. and Weber A.P.M. (2006) Metabolite transporters in control of primary plant metabolism. In: Control of Primary Metabolism in Plants. (Eds) W. C. Plaxton and M. T. McManus. Blackwell Publishing. 85-120.

Gerdemann-Knoerck M. and Tegeder M. (1997) Compendium of genetically modified plants relevant for field releases: Brassicacea, Beta vulgaris, Linum usitatissimum. pp 1-221. Environmental Federal Office, Berlin.