Office Address

1445 Gortner Avenue
St. Paul, MN 55108
United States

John M.


Plant and Microbial Biology

We are interested in the mechanisms used by cells to take up and export nutrients and metabolites and the physiological processes that depend on transmembrane transport. We study transporter proteins mainly by heterologous expression in Xenopus oocytes and electrophysiology (two-electrode voltage clamping).

Research interests

In my lab we are interested in the function of transporters, pumps, and channels in plants. These are membrane proteinsthat control the flow of solutes into and out of cells and cellular organelles. Our main focus is on metabolite transporters in the plasma membrane and their role in long-distance transport in plant vascular tissue. We use the tools of molecular biology, electrophysiology, and genetics to study membrane protein structure/function and transgenic approaches to understand the roles of genes encoding membrane proteins in plants.

Selected publications

Taylor, M., Reinders, A., Ward, J.M. (2015) Transport function of rice amino acid permeases (AAPs). Plant and Cell Physiology 56: 1355-63

Knoblauch, M., Vendrell, M., de Leau, E., Paterlini, A., Knox, K., Ross-Elliot, T., Reinders, A., Brockman, S.A., Ward, J.M. Oparka, K. (2015) Multispectral phloem-mobile probes: properties and applications. Plant Physiol 167: 1211-20

Reinders, A., Ward, J.M. (2015) Investigating polymorphisms in membrane-associated transporter protein SLC45A2, using sucrose transporters as a model. Mol Med Rep 12: 1393-8

Sun Y, Ward JM (2012) Arg188 in rice sucrose transporter OsSUT1 is crucial for substrate transport. BMC Biochem. 13:26

Reinders A, Sun Y, Karvonen KL, Ward JM (2012) Identification of amino acids important for substrate specificity in sucrose transporters using gene shuffling. J. Biol. Chem. 287: 30296-304

Gora PJ, Reinders A, Ward JM (2012) A novel fluorescent assay for sucrose transporters. Plant Methods 8:13

Eom JS, Choi SB, Ward JM, Jeon JS (2012) The mechanism of phloem loading in rice (Oryza sativa). Mol Cells 33: 431-438

Reinders A, Sivitz AB, Ward JM (2012) Evolution of plant sucrose uptake transporters (SUTs). Front. Plant Sci. 3: 00022

Sun Y, Lin Z, Reinders A, Ward JM (2012) Functionally Important Amino Acids in Rice Sucrose Transporter OsSUT1 Biochemistry 51: 3284-3291

Tegeder M, Ward JM (2012) Molecular evolution of AAP and LHT amino acid transporters in the plant kingdom. Front. Plant Sci. 3: 00021

Eom JS, Cho JI, Reinders A, Lee SW, Yoo Y, Tuan PQ, Choi SB, Bang G, Park YI, Cho MH, Bhoo SH, An G, Hahn TR, Ward JM, Jeon JS (2011) Impaired function of the tonoplast-localized sucrose transporter in rice, OsSUT2, limits the transport of vacuolar reserve sucrose and affects plant growth. Plant Physiol 157: 109-119

Sun Y, Reinders A, LaFleur KR, Mori T, Ward JM. (2010) Transport activity of rice sucrose transporters OsSUT1 and OsSUT5. Plant Cell Physiol. 51:114-22.

Tian H, Baxter IR, Lahner B, Reinders A, Salt DE, Ward JM (2010) Arabidopsis NPCC6/NaKR1 Is a Phloem Mobile Metal Binding Protein Necessary for Phloem Function and Root Meristem Maintenance. Plant Cell 12: 3963-3979

Hammes UZ, Meier S, Dietrich D, Ward JM, Rentsch D (2010) Functional properties of the Arabidopsis peptide transporters AtPTR1 and AtPTR5. J Biol Chem 285: 39710-39717

Ward JM, Mäser P, Schroeder JI. (2009) Plant Ion Channels: Gene Families, Physiology, and Functional Genomics Analysis. Annu Rev Physiol.71: 59-82.

Weise A, Lalonde S, Kühn C, Frommer WB, Ward JM (2008) Introns control expression of sucrose transporter LeSUT1 in trichomes, companion cells and in guard cells. Plant Mol. Biol. 68: 251-262

Reinders A, Sivitz AB, Starker CG, Gantt JS, Ward JM (2008) Functional analysis of LjSUT4, a vacuolar sucrose transporter from Lotus japonicus. Plant Mol. Biol. 68: 289-299

Sivitz AB, Reinders A, Ward JM. Arabidopsis sucrose transporter AtSUC1 is important for pollen germination and sucrose-induced anthocyanin accumulation. Plant Physiol. 2008 May;147(1):92-100.

Zhao J, Cheng NH, Motes CM, Blancaflor EB, Moore M, Gonzales N, Padmanaban S, Sze H, Ward JM, Hirschi KD. AtCHX13 is a plasma membrane K+ transporter. Plant Physiol.2008 Oct;148(2):796-807.

Morris J, Tian H, Park S, Sreevidya CS, Ward JM, Hirschi KD. (2008) AtCCX3 is an Arabidopsis endomembrane H+ -dependent K+ transporter. Plant Physiol.148:1474-1486.

Padmanaban, S., Chanroj, S., Kwak, J., Li, X., Ward, J. M. and Sze, H. (2007) Participation of an endomembrane cation/H+ exchanger AtCHX20 in osmoregulation of guard cells. Plant Physiol.144: 82-93.

Sivitz, A. B., Reinders, A., Johnson, M., Krentz, A. D., Grof, C. P. L., Perroux, J. M. and Ward, J. M. (2007) Arabidopsis sucrose transporter AtSUC9: high affinity transport activity, intragenic control of expression and early-flowering phenotype. Plant Physiol. 143: 188-198.

Reinders, A., Sivitz, A.B., Hsi, A., Grof, C.P.L., Perroux, J.M. and Ward, J.M. (2006). Sugarcane ShSUT1: analysis of sucrose transport activity and inhibition by sucralose. Plant Cell Env. 29: 1871-1880

Bock, K.W., Honys, D., Ward, J.M., Padmanaban, S., Nawrocki, E., Hirschi, K.D., Twell, D., and Sze, H. (2006). Integrating Membrane Transport with Male Gametophyte Development and Function through Transcriptomics. Plant Physiol.240:1151-1168.

Reinders, A., Panshyshyn, J.A., Ward, J.M. (2005). Analysis of transport activity of Arabidopsis sugar alcohol permease homolog AtPLT5. J. Biol. Chem.280, 1594-1602.

Shigaki, T., Kole, M., Ward, J.M., Sze, H., Hirschi, K.D. (2005). Cre-loxP recombination vectors for the expression of Riken Arabidopsis full-length cDNAs in plants. Biotechniques. 39:301-302.

Sivitz, A.B., Reinders, A., Ward, J.M. (2005). Analysis of the Transport Activity of Barley Sucrose Transporter HvSUT1. Plant Cell Physiol.46:1666-1673).


Ph.D., University of Maryland, 1991