Elongation factor 1α from A. thaliana functions as molecular chaperone and confers resistance to salt stress in yeast and plants

Salt stress is a major environmental factor influencing plant growth and development and plants have many tolerance mechanisms to overcome salt stress. To identify salt tolerance determinants in higher plants, an Arabidopsis cDNA clone that encodes translation elongation factor 1 alpha (AtEF1α) was isolated by functional complementation of the salt-sensitive phenotype of a calcineurin (CaN)-deficient yeast mutant (cnbΔ). AtEF1α displayed a chaperone activity in a dose-dependant manner in vitro and the chaperone activity of AtEF1α was required for NaCl tolerance in cnbΔ cells. When compared with wild-type Arabidopsis, AtEF1α knock-out plants were more sensitive to NaCl stress. Furthermore, transgenic plants with transgene AtEF1α were more tolerant to NaCl than the wild-type. These results suggest that AtEF1α functions as molecular chaperone, and this activity enhances NaCl tolerance in yeast and plants.