The effect of salinity stress on Na+, K+ concentration, Na+/K+ ratio, electrolyte leakage and HKT expression profile in roots of Aeluropus littoralis

Document Type : Original research paper


1 Department of Plant Biotechnology, University of Jahrom, Iran

2 Department of Plant Breeding and Biotechnology, Ferdowsi University of Mashhad, Iran

3 Institute of Biotechnology, Collage of Agriculture, Shiraz University, Iran

4 Department of Plant Breeding and Biotechnology, Shirvan University, Iran


Among abiotic stresses, salinity has been increasing over the time for many reasons like using chemical fertilizers, global warming and rising sea levels. Under salinity stress, the loss of water availability, toxicity of Na+ and ion imbalance directly reduces carbon fixation and biomass production in plants. K+ is a major agent that can counteract Na+ stresses, thus the potential of plants to tolerate salinity is strongly dependent on their potassium nutrition. HKTs (High-affinity K+ Transporters) are a family of transporters that mediate Na+-specific or Na+-K+ transport and play a key role in the regulation of ion homeostasis. In this study, we intended to focus on Electrolyte Leakage, ratio of K+/Na+, transcriptomic responses of a subclass two HKT in the roots of Aeluropus littoralis under salt stress. We investigated a noticeably different expression pattern over studied time points and found a snappy increase of AlHKT and rebalance of K+ concentration. It can be suggested that the early and high response of a Na+-K+ coupled transporter acted as a part of A. littoralis salt tolerance.


[1]      Ahmad, I. and Maathuis, F. J. 2014. Cellular and tissue distribution of potassium: physiological relevance, mechanisms and regulation. Journal of plant physiology 171(9): 708-714.
[2]      Babgohari, M. Z., Niazi, A., Moghadam, A. A., Deihimi, T. and Ebrahimie, E. 2013. Genome-wide analysis of key salinity-tolerance transporter (HKT1; 5) in wheat and wild wheat relatives (A and D genomes). In Vitro Cellular & Developmental Biology-Plant 49(2): 97-106.
[3]      Bañuelos, M. A., Haro, R., Fraile-Escanciano, A. and Rodríguez-Navarro, A. 2008. Effects of polylinker uATGs on the function of grass HKT1 transporters expressed in yeast cells. Plant and cell physiology 49(7): 1128-1132.
[4]      Barhoumi, Z., Djebali, W., Smaoui, A., Chaïbi, W. and Abdelly, C. 2007. Contribution of NaCl excretion to salt resistance of Aeluropus littoralis (Willd) Parl. Journal of plant physiology 164(7): 842-850.
[5]      Barkla, B. J. and Blumwald, E. 1991. Identification of a 170-kDa protein associated with the vacuolar Na+/H+ antiport of Beta vulgaris. Proceedings of the National Academy of Sciences 88(24): 11177-11181.
[6]      Benito, B., Haro, R., Amtmann, A., Cuin, T. A. and Dreyer, I. 2014. The twins K+ and Na+ in plants. Journal of plant physiology 171(9): 723-731.
[7]      Berthomieu, P., Conéjéro, G., Nublat, A., Brackenbury, W. J., Lambert, C., Savio, C., Uozumi, N., Oiki, S., Yamada, K. and Cellier, F. 2003. Functional analysis of AtHKT1 in Arabidopsis shows that Na+ recirculation by the phloem is crucial for salt tolerance. The EMBO Journal 22(9): 2004-2014.
[8]      Chen, Z., Zhou, M., Newman, I. A., Mendham, N. J., Zhang, G. and Shabala, S. 2007. Potassium and sodium relations in salinised barley tissues as a basis of differential salt tolerance. Functional Plant Biology 34(2): 150-162.
[9]      Cramer, G. R., Lynch, J., Läuchli, A. and Epstein, E. 1987. Influx of Na+, K+, and Ca2+ into roots of salt-stressed cotton seedlings effects of supplemental Ca2+. Plant Physiology 83(3): 510-516.
[10]    Datta, K. and Datta, S. K. (2006). Indica rice (Oryza sativa, BR29 and IR64). Agrobacterium Protocols, Springer: 201-212.
[11]    Enders, A. and Lehmann, J. 2012. Comparison of wet-digestion and dry-ashing methods for total elemental analysis of biochar. Communications in soil science and plant analysis 43(7): 1042-1052.
[12]    Evans, H. J. and Sorger, G. J. 1966. Role of mineral elements with emphasis on the univalent cations. Annual review of plant physiology 17(1): 47-76.
[13]    Garciadeblas, B., Benito, B. and Rodríguez-Navarro, A. 2002. Molecular cloning and functional expression in bacteria of the potassium transporters CnHAK1 and CnHAK2 of the seagrass Cymodocea nodosa. Plant molecular biology 50(4-5): 623-633.
[14]    Gierth, M. and Mäser, P. 2007. Potassium transporters in plants–involvement in K+ acquisition, redistribution and homeostasis. FEBS letters 581(12): 2348-2356.
[15]    Gregorio, G. B., Senadhira, D. and Mendoza, R. D. 1997. Screening rice for salinity tolerance. International Rice Research Institute discussion paper series (22).
[16]    Hakim, M., Juraimi, A. S., Hanafi, M., Ali, E., Ismail, M. R., Selamat, A. and Karim, S. R. 2014. Effect of salt stress on morpho-physiology, vegetative growth and yield of rice. Journal of Environmental Biology 35: 317-326.
[17]    Hauser, F. and Horie, T. 2010. A conserved primary salt tolerance mechanism mediated by HKT transporters: a mechanism for sodium exclusion and maintenance of high K+/Na+ ratio in leaves during salinity stress. Plant, cell & environment 33(4): 552-565.
[18]    Horie, T., Hauser, F. and Schroeder, J. I. 2009. HKT transporter-mediated salinity resistance mechanisms in Arabidopsis and monocot crop plants. Trends in plant science 14(12): 660-668.
[19]    Horie, T., Yoshida, K., Nakayama, H., Yamada, K., Oiki, S. and Shinmyo, A. 2001. Two types of HKT transporters with different properties of Na+ and K+ transport in Oryza sativa. The Plant Journal 27(2): 129-138.
[20]    Huang, S., Spielmeyer, W., Lagudah, E. S. and Munns, R. 2008. Comparative mapping of HKT genes in wheat, barley, and rice, key determinants of Na+ transport, and salt tolerance. Journal of experimental botany 59(4): 927-937.
[21]    James, R. A., Blake, C., Byrt, C. S. and Munns, R. 2011. Major genes for Na+ exclusion, Nax1 and Nax2 (wheat HKT1; 4 and HKT1; 5), decrease Na+ accumulation in bread wheat leaves under saline and waterlogged conditions. Journal of Experimental Botany 62(8): 2939-2947.
[22]    James, R. A., Davenport, R. J. and Munns, R. 2006. Physiological characterization of two genes for Na+ exclusion in durum wheat, Nax1 and Nax2. Plant Physiology 142(4): 1537-1547.
[23]    Kao, W.-Y. 2011. Na, K and Ca Contents in Roots and Leaves of Three Glycine Species Differing in Response to NaCl Treatments. Taiwania 56(1): 17-22.
[24]    Khan, M., Shirazi, M., Khan, M. A., Mujtaba, S., Islam, E., Mumtaz, S., Shereen, A., Ansari, R. and Ashraf, M. Y. 2009. Role of Proline, K/Na Ratio And Chlorophyll Content In Salt Tolerance of Wheat (Triticum aestivum L.). Pak. J. Bot 41(2): 633-638.
[25]    Korn, S. J. and Ikeda, S. R. 1995. Permeation selectivity by competition in a delayed rectifier potassium channel. Science 269(5222): 410.
[26]    Maathuis, F. J. and Amtmann, A. 1999. K+ nutrition and Na+ toxicity: the basis of cellular K+/Na+ ratios. Annals of Botany 84(2): 123-133.
[27]    Martínez-Cordero, M. A., Martínez, V. and Rubio, F. 2004. Cloning and functional characterization of the high-affinity K+ transporter HAK1 of pepper. Plant molecular biology 56(3): 413-421.
[28]    Mäser, P., Gierth, M. and Schroeder, J. I. 2002. Molecular mechanisms of potassium and sodium uptake in plants. Plant and soil 247(1): 43-54.
[29]    Mian, A., Oomen, R. J. F. J., Isayenkov, S., Sentenac, H., Maathuis, F. J. M. and Véry, A.-A. 2011. Over-expression of an Na+- and K+-permeable HKT transporter in barley improves salt tolerance. The Plant Journal 68(3): 468-479.
[30]    Nieves-Cordones, M., Alemán, F., Martínez, V. and Rubio, F. 2014. K+ uptake in plant roots. The systems involved, their regulation and parallels in other organisms. Journal of plant physiology 171(9): 688-695.
[31]    Pfaffl, M. W. 2001. A new mathematical model for relative quantification in real-time RT–PCR. Nucleic acids research 29(9): e45-e45.
[32]    Platten, J. D., Cotsaftis, O., Berthomieu, P., Bohnert, H., Davenport, R. J., Fairbairn, D. J., Horie, T., Leigh, R. A., Lin, H.-X. and Luan, S. 2006. Nomenclature for HKT transporters, key determinants of plant salinity tolerance. Trends in plant science 11(8): 372-374.
[33]    Roy, S. J., Tucker, E. J. and Tester, M. 2011. Genetic analysis of abiotic stress tolerance in crops. Current opinion in plant biology 14(3): 232-239.
[34]    Su, H., Golldack, D., Zhao, C. and Bohnert, H. J. 2002. The expression of HAK-type K+ transporters is regulated in response to salinity stress in common ice plant. Plant Physiology 129(4): 1482-1493.
[35]    Su, Q., Feng, S., An, L. and Zhang, G. 2007. Cloning and functional expression in Saccharomyces cereviae of a K+ transporter, AlHAK, from the graminaceous halophyte, Aeluropus littoralis. Biotechnology letters 29(12): 1959-1963.
[36]    Véry, A.-A., Nieves-Cordones, M., Daly, M., Khan, I., Fizames, C. and Sentenac, H. 2014. Molecular biology of K+ transport across the plant cell membrane: what do we learn from comparison between plant species? Journal of plant physiology 171(9): 748-769.
[37]    Wigoda, N., Moshelion, M. and Moran, N. 2014. Is the leaf bundle sheath a “smart flux valve” for K+ nutrition? Journal of plant physiology 171(9): 715-722.
Volume 3, Issue 2 - Serial Number 2
December 2015
Pages 1-10
  • Receive Date: 02 August 2015
  • Revise Date: 25 October 2015
  • Accept Date: 21 November 2015
  • First Publish Date: 01 December 2015