Functional Study Of Wheat Abiotic Stress Transcription Factor TabZIP15

bZIP protein is a common family of transcription factors in eukaryotes,it is not only involved in regulating a variety of biological processes,but also plays an important role in the response of plants to stress,however,there are still preliminary studies on the functional of bZIP transcription factors induced by abiotic stress in wheat.In this study,firstly,based on the results of the functional verification of TabZIP15 transgenic Arabidopsis thaliana in the early laboratory,we overexpressed TabZIP15 gene in wheat,conducted sequence analysis,subcellular localization,expression analysis and functional verification of this gene,thus analyze the regulatory mechanism of TabZIP15 resistance to abiotic stress in wheat.Secondly,based on the results of transcriptome sequencing,we analyzed the expression profile of bZIP family transcription factors under salt stress,in order to provide candidate genes for further study of the function of bZIP family transcription factors in response to salt stress in wheat.Sequence analysis indicated that TabZIP15 is 1 255 bp in full length with a 756 bp ORF,encoding 251 amino acids with a predicted molecular mass of 27.178 kD and the isoelectric point is 8.38,The protein secondary structure was predicted to contain 4 alpha-helices.Homologous evolution analysis shows that TabZIP15 had a high similarity to a sequence from Aegilops tauschii.The results of subcellular localization showed that TabZIP15 was a protein located in the cell nucleus.qRT-PCR analysis showed that the expression of TabZIP15 could be induced after low temperature,ABA,PEG and salt treatment,and the expression of TabZIP15 was different in different tissues.In order to verify the function of TabZIP15 in wheat under drought and salt stress,it was overexpressed in KN199.The phenotypic observation of salt tolerance in seedling stage showed that the above ground growth of four TabZIP15 transgenic strains and wild type KN199 in salt treatment group were inhibited to varying degrees.The main physiological indexes showed that salt stress would seriously reduce the plant height and fresh weight of wheat seedlings,and the TabZIP15 transgenic strain could maintain higher plant height,fresh weight of aboveground,root length and fresh weight of root after salt stress compared with wild type KN199.The results of repeated drought experiment in seedling stage showed that most of the materials could survive after the 1st drought treatment,and the average survival rate of TabZIP15 transgenic strain was 92.08%,after the 2nd drought treatment,the average survival rate of TabZIP15 transgenic strain was reduced to 35.61%,after the 3rd drought treatment,the average survival rate of TabZIP15 transgenic strain was only 3.46%.Moreover,the survival rate of TabZIP15 transgenic strain was significantly higher than that of the control KN199,it means that TabZIP15 transcription factor could improve drought resistance of wheat at seedling stage.qRT-PCR analysis showed that the expression of 9 stress-resistant genes in TabZIP15 was significantly higher than that of KN199.These results showed that the overexpression of TabZIP15 gene enhanced the ability of transgenic wheat to resist abiotic stress by activating the expression of stress resistance related genes.In order to study whether the bZIP family transcription factor gene was involved in the regulation of salt stress response in wheat,obtaining more bZIP transcription factors related to salt stress,and used KN199 as the experimental material,the differential expression of bZIP family transcription factor gene in wheat under salt stress was analyzed by transcriptome sequencing.The quality analysis of transcriptome sequencing data shows that the sample sequencing quality was good.The results of RNA-Seq cluster analysis showed that the correlation coefficient between biological repeats of each treatment was above 0.97.PCA shows that the difference between the samples at different time points was very significant.The results of chromosome distribution statistics showed that 14 of the 156 bZIP family genes screened from Chinese Spring(CS)reference genome were located on chromosome 5B.The results of differentially expressed genes analysis showed that 14 544 DEGs including 49 bZIP transcription factor genes were identified 1 hour after salt treatment,and 25 546 DEGs including 59 bZIP transcription factor genes were identified 6 hours after salt treatment,and there were 35 bZIP transcription factors common DEGs between the two groups of samples,25 of which were up-regulated expression and 10 down regulated expression.Cluster analysis of bZIP transcription factor genes in response to salt stress showed that the results were consistent with those of gene expression difference analysis.It was found that the number of total DEGs and differentially expressed bZIP transcription factor genes increased with the increase of processing time,It is suggested that these genes may play an important role in the process of regulating salt stress response in wheat,make a profound study of these genes was conducive to the analysis of the mechanism of salt resistance regulation in wheat.