Stress tolerance and glucose insensitive phenotypes in Arabidopsis overexpressing the CpMYB10 transcription factor gene.

The resurrection plant Craterostigma plantagineum has the ability to survive complete dehydration. In an attempt to further understand desiccation tolerance in this plant, the CpMYB10 transcription factor gene was functionally characterized. CpMYB10 is rapidly induced by dehydration and abscisic acid (ABA) treatments in leaves and roots, but no expression was detected in fully hydrated tissues. Electrophoretic mobility shift assay experiments showed binding of rCpMYB10 to specific mybRE elements within the LEA Cp11-24 and CpMYB10 promoters. Localization of CpMYB10 transcript by in situ reverse transcription-PCR reactions showed expression in vascular tissues, parenchyma, and epidermis both in leaves and roots in response to ABA. Transgenic Arabidopsis plants transformed with CpMYB10 promoter fused to GUS gene showed reporter expression under ABA and stress conditions in several organs. Overexpression of CpMYB10 cDNA in Arabidopsis led to desiccation and salt tolerance of transgenics lines. Interestingly, it was found that plants overexpressing CpMYB10 exhibited Glc-insensitive and ABA hypersensitive phenotypes. Therefore, our results indicate that CpMYB10 in Arabidopsis is mediating stress tolerance and altering ABA and Glc signaling responses.