Class I
|
AtHTK1;1 |
Arabidopsis |
Na+
|
Roots: Xylem parenchyma, phloem Shoots: Phloem |
PM |
Unload Na+ from the xylem transpiration stream Load of Na+ into shoot pholem |
Berthomieu et al., 2003Berthomieu P, Conejero G, Nublat A, Brackenbury WJ, Lambert C, Savio C, Uozumi N, Oik S, Yamada K, Cellier F, et al. (2003) Functional analysis of AtHKT1 in Arabidopsis shows that Na+ recirculation by the phloem is crucial for salt tolerance. EMBO J 22:2004-2014.; Møller et al., 2009Møller IS, Gilliham M, Jha D, Mayo GM, Roy SJ, Coates JC, Haseloff J and Tester M (2009) Shoot Na+ exclusion and increased salinity tolerance engineered by cell type-specific alteration of Na+ transport in Arabidopsis. Plant Cell 7:2163-2178.; Sunarpi et al., 2005Sunarpi HT, Motoda J, Kubo M, Yang H, Yoda K, Horie R, Chan WY, Leung HY, Hattori K, et al. (2005) Enhanced salt tolerance mediated by AtHKT1 transporter-induced Na unloading from xylem vessels to xylem parenchyma cells. Plant J. 44:928-938.
|
OsHTK1;1 |
Rice |
Na+
|
Roots: Similar as OsHKT2;1 Leaves: Bulliform cells and vascular tissues |
PM |
N/A |
Jabnoune et al., 2009Jabnoune M, Espeout S, Mieulet D, Fizames C, Verdeil JL, Conejero G, Rodríguez-Navarro A, Sentenac H, Guiderdoni E, Abdelly C, et al. (2009) Diversity in expression patterns and functional properties in the rice HKT transporter family. Plant Physiol 150:1955-1971.
|
OsHTK1;2 |
Rice |
N/A |
N/A |
PM |
N/A |
Wu et al., 2009Wu Y, Hu Y and Xu G (2009) Interactive effects of potassium and sodium on root growth and expression of K+/Na+ transporter genes in rice. Plant Growth Regulation 57:271-280.
|
OsHTK1;3 |
Rice |
Na+
|
Roots: Cortex and vascular tissues in the stele. Leaves: Bulliform cells and vascular tissues, mesophyll cells. |
PM |
N/A |
Jabnoune et al., 2009Jabnoune M, Espeout S, Mieulet D, Fizames C, Verdeil JL, Conejero G, Rodríguez-Navarro A, Sentenac H, Guiderdoni E, Abdelly C, et al. (2009) Diversity in expression patterns and functional properties in the rice HKT transporter family. Plant Physiol 150:1955-1971.
|
OsHTK1;4 |
Rice |
N/A |
Leaves sheaths |
PM |
Control of sheath to blade transfer of Na+
|
Cotsaftis et al., 2012Cotsaftis O, Plett D, Shirley N, Tester M and Hrmova M (2012) A two-staged model of Na+ exclusion in rice explained by 3D modeling of HKT transporters and alternative splicing. PLoS ONE 7:e39865.
|
OsHTK1;5 |
Rice |
Na+
|
Roots and Shoots: Xylem parenchyma |
PM |
Unload Na+ from the xylem transpiration stream |
Ren et al., 2005Ren ZH, Gao JP, Li LG, Cai XL, Huang W, Chao DY, Zhu MZ, Wang ZY, Luan S and Lin HX (2005) A rice quantitative trait locus for salt tolerance encodes a sodium transporter. Nat Genet 37:1141-1146.
|
TaHKT1;4 |
Wheat |
Na+
|
Roots and Leaves |
PM |
Unload Na+ from the xylem transpiration stream |
Huang et al., 2006Huang S, Spielmeyer W, Lagudah ES, James RA, Platten JD, Dennis ES and Munns R (2006) A sodium transporter (HKT7) is a candidate for Nax1, a gene for salt tolerance in durum wheat. Plant Physiol. 142:1718-1727.
|
TaHKT1;5 |
Wheat |
Na+
|
Roots |
PM |
Unload Na+ from the xylem transpiration stream |
Byrt et al., 2007Byrt CS, Platten JD, Spielmeyer W, James RA, Lagudah ES, Dennis ES, Tester M and Munns R (2007) HKT1;5-like cation transporters linked to Na+ exclusion loci in wheat, Nax2 and Kna1. Plant Physiol 143:1918-1928.;Munns et al., 2012Munns R, James RA, Xu B, Athman A, Conn SJ, Jordans C, Byrt CS, Hare RA, Tyerman SD, Tester M, et al. (2012) Wheat grain yield on saline soils is improved by an ancestral Na+ transporter gene. Nat Biotechnol 30:360-364.
|
Class II
|
OsHKT2;1 |
Rice |
Na+/K+
|
Roots: Epidermis, exodermis, cortex differentiated into aerenchyma, stele (mainly pholem). Leaves: Bulliform cells, xylem, phloem, mesophyll cells. |
PM |
Nutritional Na+ uptake from the external medium. |
Jabnoune et al., 2009Jabnoune M, Espeout S, Mieulet D, Fizames C, Verdeil JL, Conejero G, Rodríguez-Navarro A, Sentenac H, Guiderdoni E, Abdelly C, et al. (2009) Diversity in expression patterns and functional properties in the rice HKT transporter family. Plant Physiol 150:1955-1971.; Horie et al., 2007Horie T, Costa A, Kim TH, Han MJ, Horie R, Leung HY, Miyao A, Hirochika H, An G and Schroeder JI (2007) Rice OsHKT2;1 transporter mediates large Na+ influx component into K+-starved roots for growth. EMBO J 20:3003-3014.
|
OsHKT2;2 |
Rice |
Na+/K+
|
Roots |
PM |
Na+ and K+ uptake under K+ starvation conditions. |
Yao et al., 2010Yao X, Horie T, Xue S, Leung HY, Katsuhara M, Brodsky DE, Wu Y and Schroeder JI (2010) Differential sodium and potassium transport selectivities of the rice OsHKT2;1 and OsHKT2;2 transporters in plant cells. Plant Physiol 152:341-355.; Oomen et al., 2012Oomen RJ, Benito B, Sentenac H, Rodríguez-Navarro A, Talón M, Véry AA and Domingo C (2012) HKT2;2/1, a K+-permeable transporter identified in a salt-tolerant rice cultivar through surveys of natural genetic polymorphism. Plant J 71:750-762.
|
TaHKT2;1 |
Wheat |
Na+/K+
|
Roots: Cortical and stele Leaves: Vasculature tissue of mesophyll. |
PM |
Na+ uptake from external medium. |
Schachtman and Schroeder, 1994Schachtman DP and Schroeder JI (1994) Structure and transport mechanism of a high-affinity potassium uptake transporter from higher plants. Nature.370:655-658.
|
HvHKT2;1 |
Barley |
Na+/K+
|
Roots: Cortex. Leaves: Blade and sheath. |
PM |
K+ uptake at very low K+ concentrations (possible) and uptake of Na+ in the roots (possible). |
Mian et a., 2011Mian A, Oomen RJ, Isayenkov S, Sentenac H, Maathuis FJ and Very AA (2011) Over-expression of an Na+-and K+-permeable HKT transporter in barley improves salt tolerance. Plant J 68:468-479.; Haro et al., 2005Haro R, Bañuelos MA, Senn ME, Barrero-Gil J and Rodríguez-Navarro A (2005) HKT1 mediates sodium uniport in roots. Pitfalls in the expression of HKT1 in yeast. Plant Physiol. 139:1495-1506.
|