Overexpression of the Poplar WRKY51 Transcription Factor Enhances Salt Tolerance in Arabidopsis thaliana

Salt is a severe environmental stressor that affects growth and development in plants. It is significant to enhance the salt tolerance in plants. In this study, a salt-responsive WRKY transcription factor PtrWRKY51 was isolated from Populus trichocarpa (clone 'Nisqually-1 '). PtrWRKY51 was highly expressed in mature leaves and root and induced by salt stress. The PtrWRKY51 was overexpressed in Arabidopsis to investigate its biological functions. Compared with Col-0 lines, Overexpressed lines had an increase in germination rate of seed, root length, higher photosynthetic rate, instantaneous leaf WUE, chlorophyll content to improve salt tolerance under salt stress conditions. In contrast, compared to overexpressed and Col-0 lines, the mutant wrky51 was more sensitive to salt stress with lower photosynthetic rate and WUE. Additionally, it was found that the complementary lines (wrky51/ PtrWRKY51) had almost the same salt response as Col-0. In conclusion, PtrWRKY51 is a potential target in the enhancement of poplar tolerance by genetic engineering strategies.