Expression of Two α-Type Expansins from Ammopiptanthus nanus in Arabidopsis thaliana Enhance Tolerance to Cold and Drought Stresses

摘要

Expansins, cell-wall loosening proteins, play an important role in plant growth and development and abiotic stress tolerance. ( ) is an important plant to study to understand stress resistance in forestry. In our previous study, two α-type expansins from were cloned and named and . In this study, we found that they responded to different abiotic stress and hormone signals. It suggests that they may play different roles in response to abiotic stress. Their promoters show some of the same element responses to abiotic stress and hormones, but some special elements were identified between the expansins that could be essential for their expression. In order to further testify the reliability of the above results, we conducted an analysis of β-glucuronidase (GUS) dyeing. The analysis showed that was only induced by cold stress, whereas responded to hormone induction. and transgenic plants showed better tolerance to cold and drought stresses. Moreover, the ability to scavenge reactive oxygen species (ROS) was significantly improved in the transgenic plants, and expansin activity was enhanced. These results suggested that and play an important role in the response to abiotic stress. Our research contributes to a better understanding of the regulatory network of expansins and may benefit agricultural production.