Expression And Functional Analyses Of Wheat Transcription Factor Gene TaNAC8B

Adverse factors such as drought, high salinity, extreme temperature severely affect the normal growth and development of plants, resulting in decrease of crop productivity and quality. During long-time evolution process, plants have formed a series of defense mechanisms by, e.g. regulating the expressions of different genes against adverse environmental impacts, such as transcription factors(TFs). Transcription factors can bind to their corresponding cis-acting sequences to regulate gene expression temporally and spatially. NAC(NAM, ATAF, and CUC) TFs, as one of the biggest families of TFs, have been reported to play important roles in response to stresses. Most of the researches on NAC TFs were focused on model plant Arabidopsis and rice, while the functional analysis of NAC TFs in the wheat is quite limited. Previously, one member of TaNAC named TaNAC8 B was cloned from wheat in our lab. My research was to study the function of TaNAC8 B through the gene expression pattern analysis and transgenic approach. The main results are as follows:(1) The expression profiles analyses by semi-quantatative RT-PCR method showed that TaNAC8 B expression was increased strongly following the treatment with PEG6000. While there was no obvious expression changes of TaNAC8 B with treatments of salt, ABA and low temperature(LT).(2) We have constructed the eukaryotic expression vector of pGBKT7-TaNAC8 B. TaNAC8 B was proved to have transcriptional activation activities in yeast. And only variable region of the carboxyl terminal of TaNAC8 B shows the transcriptional activation activity.(3) We successfully transformed TaNAC8 B into tobacco and obtained positive transgenic plants via Agrobacterium tumefaciens-mediated transformation method. Stresses assay showed that transgenic lines overexpressing TaNAC8 B had better stress tolerance as indicated by root length, phenotypic analysis and determination of related physiological indexes experiments. It was consistent with the experimental results of TaNAC8 B gene expression pattern analysis.In conclusion, TaNAC8 B transcription factors can respond to drought stress treatment. TaNAC8B-over expression plants had better drought stress tolerance. Results of present study provided useful information for further investigation on the functions of TaNAC8 B.