Expression of an arctic chickweed dehydrin, CarDHN, enhances tolerance to abiotic stress in tobacco plants

Dehydrin proteins are known to serve a wide variety of intracellular protective functions and enhance the capability of plants to deal with abiotic stresses. The gene for a SK5 type dehydrin from the arctic chickweed plant Cerastium arcticum (CarDHN) was introduced into tobacco plants. Stress responses of the transgenic plants were evaluated. Compared to the untransformed wild type plants, the CarDHN-expressing plants exhibited improved tolerance to salt and osmotic stress during seed germination and seedling growth, and survived in -10 A degrees C freezing treatment. These CarDHN plants also accumulated lower levels of free proline under salt stress and exhibited lower transcription levels of HSP70 and HSP26 under drought or salt stress, suggesting a possible pleiotropic effect of CarDHN on stress response at cellular or molecular level. However, no significant phenotypic differences were observed between the wild type and the CarDHN-expressing plants under drought stress. Our study demonstrated the specific role of the arctic chickweed dehydrin in tolerance to salt, osmotic and freezing stress.