Overexpression of a Fragaria vesca MYB Transcription Factor Gene (FvMYB82) Increases Salt and Cold Tolerance in Arabidopsis thaliana

Abstract

The MYB transcription factor (TF) family is one of the largest transcription families in plants, which is widely involved in the responses to different abiotic stresses, such as salt, cold, and drought. In the present study, a new MYB TF gene was cloned from <i>Fragaria vesca</i> (a diploid strawberry) and named <i>FvMYB82</i>. The open reading frame (ORF) of <i>FvMYB82</i> was found to be 960 bp, encoding 319 amino acids. Sequence alignment results and predictions of the protein structure indicated that the <i>FvMYB82</i> contained the conserved R2R3-MYB domain. Subcellular localization analysis showed that <i>FvMYB82</i> was localized onto the nucleus. Furthermore, the qPCR showed that the expression level of <i>FvMYB82</i> was higher in new leaves and roots than in mature leaves and stems. When dealing with different stresses, the expression level of <i>FvMYB82</i> in <i>F. vesca</i> seedlings changed markedly, especially for salt and cold stress. When <i>FvMYB82</i> was introduced into <i>Arabidopsis thaliana</i>, the tolerances to salt and cold stress of <i>FvMYB82</i>-OE <i>A. thaliana</i> were greatly improved. When dealt with salt and cold treatments, compared with wild-type and unloaded line (UL) <i>A. thaliana</i>, the transgenic lines had higher contents of proline and chlorophyll, as well as higher activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). However, the transgenic <i>A. thaliana</i> had lower level of malondialdehyde (MDA) and electrolytic leakage (EL) than wild-type and UL <i>A. thaliana</i> under salt and cold stress. Meanwhile, <i>Fv</i><i>MYB82</i> can also regulate the expression of downstream genes associated with salt stress (<i>AtSnRK2.4</i>, <i>AtSnRK2.6</i>, <i>AtKUP6</i>, and <i>AtNCED3</i>) and cold stress (<i>AtCBF1</i>, <i>AtCBF2</i>, <i>AtCOR15a</i>, and <i>AtCOR78</i>). Therefore, these results indicated that <i>FvMYB82</i> probably plays an important role in the response to salt and cold stresses in <i>A. thaliana</i> by regulating downstream related genes.