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Critical role of divalent cations and Na + efflux in Arabidopsis thaliana salt tolerance
Author(s) -
Elphick C. H.,
Sanders D.,
Maathuis F. J. M.
Publication year - 2001
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1046/j.0016-8025.2001.00713.x
Subject(s) - efflux , mutant , arabidopsis , wild type , divalent , calcineurin , elongation , calmodulin , chemistry , phosphatase , protein subunit , biochemistry , paclobutrazol , biology , potassium , microbiology and biotechnology , biophysics , botany , enzyme , gene , transplantation , medicine , materials science , organic chemistry , ultimate tensile strength , metallurgy
Detrimental effects of salinity on plants are known to be partially alleviated by external Ca 2+ . Previous work demonstrated that the Arabidopsis SOS3 locus encodes a Ca 2+ ‐binding protein with similarities to CnB, the regulatory subunit of protein phosphatase 2B (calcineurin). In this study, we further characterized the role of SOS3 in salt tolerance. We found that reduced root elongation of sos3 mutants in the presence of high concentrations of either NaCl or LiCl is specifically rescued by Ca 2+ and not Mg 2+ , whereas root growth is rescued by both Ca 2+ and Mg 2+ in the presence of high concentrations of KCl. Phenocopies of sos3 mutants were obtained in wild‐type plants by the application of calmodulin and calcineurin inhibitors. These data provide further evidence that SOS3 is a calcineurin‐like protein and that calmodulin plays an important role in the signalling pathways involved in plant salt tolerance. The origin of the elevated Na : K ratio in sos3 mutants was investigated by comparing Na + efflux and influx in both mutant and wild type. No difference in Na + influx was recorded between wild type and sos3; however, sos3 plants showed a markedly lower Na + efflux, a property that would contribute to the salt‐oversensitive phenotype of sos3 plants.