J Integr Plant Biol. ›› 2014, Vol. 56 ›› Issue (3): 315-332.DOI: 10.1111/jipb.12144

Special Issue: Abiotic Stresses

• Research Articles • Previous Articles    

SbHKT1;4, a member of the high-affinity potassium transporter gene family from Sorghum bicolor, functions to maintain optimal Na+/K+ balance under Na+ stress

Tian-Tian Wang1, Zhi-Jie Ren2, Zhi-Quan Liu1, Xue Feng1,4, Rui-Qi Guo1,3, Bao-Guo Li3, Le-Gong Li2* and Hai-Chun Jing1*   

  1. 1Key Laboratory of Plant Resources, Institute of Botany, the Chinese Academy of Sciences, Beijing, China
    2College of Life Sciences, Capital Normal University, Beijing, China
    3The Laboratory of Soil and Water, College of Resources and Environmental Sciences, China Agricultural University, Beijing, China
    4Shanghai Key Laboratory of Urbanization and Ecological Restoration, School of Life Science, East China Normal University, Shanghai, China

Abstract:

In halophytic plants, the high-affinity potassium transporter HKT gene family can selectively uptake K+ in the presence of toxic concentrations of Na+. This has so far not been well examined in glycophytic crops. Here, we report the characterization of SbHKT1;4, a member of the HKT gene family from Sorghum bicolor. Upon Na+ stress, SbHKT1;4 expression was more strongly upregulated in salt-tolerant sorghum accession, correlating with a better balanced Na+/K+ ratio and enhanced plant growth. Heterogeneous expression analyses in mutants of Saccharomyces cerevisiae and Arabidopsis thaliana indicated that overexpressing SbHKT1;4 resulted in hypersensitivity to Na+ stress, and such hypersensitivity could be alleviated with the supply of elevated levels of K+, implicating that SbHKT1;4 may mediate K+ uptake in the presence of excessive Na+. Further electrophysiological evidence demonstrated that SbHKT1;4 could transport Na+ and K+ when expressed in Xenopus laevis oocytes. The relevance of the finding that SbHKT1;4 functions to maintain optimal Na+/K+ balance under Na+ stress to the breeding of salt-tolerant glycophytic crops is discussed.

Wang TT, Ren ZJ, Liu ZQ, Feng X, Guo RQ, Li BG, Li LG, Jing HC (2014) SbHKT1;4, a member of the high‐affinity potassium transporter gene family from Sorghum bicolor, functions to maintain optimal Na+/K+ balance under Na+ stress. J Integr Plant Biol 56: 315–332. doi: 10.1111/jipb.12144

Key words: Sorghum bicolour, High affinity potassium transporter (HKT), Na+/K+ ratio, Na+ stress, Salt tolerance

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