1. 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.
- Author
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Wang TT, Ren ZJ, Liu ZQ, Feng X, Guo RQ, Li BG, Li LG, and Jing HC
- Subjects
- Amino Acid Sequence, Animals, Arabidopsis drug effects, Arabidopsis genetics, Arabidopsis growth & development, Arabidopsis physiology, Cation Transport Proteins chemistry, Cation Transport Proteins metabolism, Evolution, Molecular, Gene Expression Profiling, Gene Expression Regulation, Plant drug effects, Genes, Plant, Genetic Complementation Test, Ion Channel Gating drug effects, Kinetics, Molecular Sequence Data, Mutation genetics, Oocytes metabolism, Phylogeny, Plant Proteins chemistry, Plant Proteins metabolism, Saccharomyces cerevisiae drug effects, Saccharomyces cerevisiae metabolism, Salinity, Salt-Tolerant Plants drug effects, Salt-Tolerant Plants genetics, Salt-Tolerant Plants physiology, Sodium Chloride pharmacology, Sorghum drug effects, Stress, Physiological drug effects, Symporters chemistry, Symporters metabolism, Time Factors, Xenopus, Cation Transport Proteins genetics, Multigene Family, Plant Proteins genetics, Potassium metabolism, Sodium metabolism, Sorghum genetics, Sorghum physiology, Stress, Physiological genetics, Symporters genetics
- 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., (© 2013 Institute of Botany, Chinese Academy of Sciences.)
- Published
- 2014
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