A wheat R2R3-MYB gene, TaMYB30-B, improves drought stress tolerance in transgenic Arabidopsis.

The MYB-type proteins are involved in various processes of plant growth, development, and stress response. In a previous work, a polyethylene glycol (PEG) stress-induced gene, TaMYB30, which encodes a R2R3-type MYB protein was identified in wheat. In this study, the isolation and functional characterization of the TaMYB30 gene are reported. Three homologous sequences of TaMYB30 were isolated from hexaploid wheat and designated as TaMYB30-A, TaMYB30-B, and TaMYB30-D genes based on the localizations of these three sequences to chromosomes 2A, 2B, and 2D, respectively. The expression levels of these three genes were similar under PEG stress conditions, and TaMYB30-B was selected for further analysis. The TaMYB30-B protein was localized to the nucleus where it activated transcription. The detailed characterization of Arabidopsis transgenic plants that overexpress the TaMYB30-B gene revealed that the TaMYB30-B protein can improve drought stress tolerance during the germination and the seedling stages. It was also found that overexpression of TaMYB30-B resulted in altered expression levels of some drought stress-responsive genes and changes in several physiological indices, which allow plants to overcome adverse conditions. These results indicate that the TaMYB30-B protein plays important roles in plant stress tolerance, and modification of its expression may improve drought stress tolerance in crop plants.