Cloning,expression And Functional Analysis Of A Wheat Transcriptional Factor Gene TaMYB108

Plants are constantly confronted with multiple abiotic stresses,such as high salinity,drought and extreme temperatures in their growth process.In the process of adapting to the abiotic stresses,plants have developed a series of complex regulatory network.Among them,transcription factor regulation network plays an important role in response to those abiotic stresses.MYB family,one of the largest transcription factor family in plants,participates in plant abiotic stress response through a variety of mechanisms.In recent years,functions of MYB domain-contained transcription factors in different plant species have been extensively studied in response to abiotic stresses.However,little research about MYB gene function in response to abiotic stress has been reported in wheat,which is an important grain crop.In this study,a new R2R3-MYB gene,designed TaMYB108,has been cloned from wheat?Triticum aestivum L.cv.Chinese Spring?,and its function in abiotic stress response was analyzed using transgenic approach.The main results are as follows:?1?The TaMYB108 gene was identified and successfully cloned from wheat genome.?2?The expression profiles of the TaMYB108 in wheat organs?root,stem,leaf,mature root,mature stem and mature leaf?were analyzed by quantitative qRT-PCR method.The results showed that TaMYB108 was expressed at different levels in organs examined with highest expression in stems and lowest expression in leaves.?3?The expression levels of the TaMYB108 in wheat seedlings under NaCl,H₂O₂ and ABA treatments were analyzed by quantitative qRT-PCR method.The results showed that the expressions of the TaMYB108 was upregulated after the treatments.?4?The five TaMYB108 ORFs fragments including 1-870 bp,1-399 bp,217-870 bp,400-870 bp and 481-870 bp were inserted into pGBKT7 vector,respectively.The fused pGBKT7-TaMYB108 recombinants and the negative control pGBKT7 were transformed into the yeast strain AH109,respectively.The results showed that full length of TaMYB108 had transcriptional activation activity and the transcriptional activation activity region is the C-terminal of 160²89 aa.?5?TaMYB108-GFP fusion expression vector was constructed,and was transiently expressed in onion epidermal cells via particle bombardment.Subcellular localization analysis showed that TaMYB108-GFP was only localized in the nucleus.?6?Eukaryotic expression vector of pBI121-TaMYB108-GFP was constructed,and then was transformed into tobacco?Nicotiana tabacum L.cv Samsun?by Agrobacterium-mediated leaf disc transformation method.Transgenic lines overexpressing TaMYB108 showed enhanced salt tolerance compared with wild type tobacco control.Results of physiological indice analyses indicated that TaMYB108-overexpressing transgenic lines had lower ion leakage,MDA and H₂O₂ contents,higher proline and chlorophyll content and higher antioxidant enzyme activities.In summary,TaMYB108-overexpressing lines enhanced tolerance to salt stress than in WT tobacco plants.Results of present study provide useful information for further investigation on the functions of the TaMYB108.