Molecular Mechanism Of The Transcription Factor TaERFL1a-enhanced Drought Tolerance In Wheat

Wheat is one of the most important grain crops in our country.Drought is one of the main limiting factors affecting its yield.It is of great theoretical and practical value to improve wheat drought resistance.Previously,we used BSMV-VIGS technology to negatively verify the transcription factor Ta ERFL1 a mediated drought stress tolerance process in wheat.In order to positively verify the drought tolerance function of the transcription factor,we obtained homozygous transgenic wheat plants with overexpression of Ta ERFL1 a.In this study,drought stress treatment was performed on homozygous wheat transgenic lines Ta ERFL1a-OE1 and Ta ERFL1a-OE2,which overexpressed Ta ERFL1 a,and it was found that transgenic plants were more tolerant to drought stress.Then,transcriptomic sequencing was used to analyze the molecular mechanism of Ta ERFL1a’s involvement in drought stress tolerance,and the possible molecular regulatory effects of Ta ERFL1a’s involvement in drought stress were identified,and the molecular mechanism of Ta ERFL1a’s involvement in drought stress of wheat was further analyzed.The main research results are as follows:(1)The physiological mechanism of Ta ERFL1 a improving drought tolerance in wheat was studiedUnder PEG simulated drought and soil natural drought conditions,Ta ERFL1 a overexpressed transgenic wheat lines showed increased tolerance to drought stress.The transgenic plants began to show significant phenotype after 7 days of PEG simulated drought,but the degree of leaf wilting was lower than that of the control,and the water content of leaves was significantly higher than that of the control.Under natural soil drought conditions,drought stress symptoms of transgenic plants began to appear later than that of wild-type plants on the 12 th day of stress.Most leaves of transgenic plants were rehydrated for 2 days.Compared with wild-type transgenic plants,most leaves of transgenic plants recovered to grow,indicating that overexpressing Ta ERFL1 a transgenic plants improved drought tolerance of wheat.Furthermore,the stress tolerance related indexes were determined,and it was found that the contents of ascorbic acid(ASA)and glutathione(GSH),the activities of superoxide dismutase(SOD)and catalase(CAT)in transgenic plants were significantly increased,while the content of malondialdehyde(MDA)and the accumulation of hydrogen peroxide(H2O2)were significantly decreased.These results indicated that transgenic plants overexpressing Ta ERFL1 a could increase their tolerance to drought stress by improving their antioxidant capacity.(2)The molecular mechanism of Ta ERFL1 a improving drought tolerance in wheat was analyzedIn order to analyze the molecular mechanism that overexpression of Ta ERFL1 a gene enhances drought tolerance of wheat,this study used transcriptomic methods to discriminate the leaves of transgenic wheat plants overexpressing Ta ERFL1 a gene and wild-type wheat plants under drought stress for 12 days.It was found that there were 7845 and 17808 different genes in the two transgenic lines compared with the wild type under drought stress,among which 3480 genes were common.Functional classification of these differential genes showed that these differential genes were involved in water stress,glutathione metabolism,lipid metabolism,cell REDOX homeostasis and other metabolic pathways.In order to verify the expression levels of the above genes in transcriptome sequencing,q PCR was used in this study to verify the expression of the above metabolic pathway genes.It was found that the expression levels of most of the above selected genes were consistent with the transcriptome results under PEG simulated drought and soil natural stress conditions,which verified the reliability of the transcriptome results.In addition,the expression of the glutathione synthesis catalase gene DHAR was significantly induced under PEG simulated drought and soil natural stress conditions,especially in transgenic plants with overexpression of Ta ERFL1 a,indicating that Ta ERFL1 a positively regulates the expression of this gene.Furthermore,this study verified that Ta ERFL1 a regulates the expression of DHAR gene by binding to the gene promoter using yeast single hybridization.