Drought Tolerance Identification Of Transgenic Overexpressing Wheat Lines For Seven Lichen Genes And Functional Study Of EpTFIIA

Food security is the foundation of modern agriculture,and contributes to economic development,national independence,and social stability.Wheat is one of the most important food crops in the world,with total annual global production exceeding 620 million tons.Wheat comprises 20% of global food consumption and is a dietary staple of more than 35% of the world’s population.The wheat planting area in arid and semi-arid regions accounts for more than 60% of the total wheat area in my country.Therefore,improving the drought resistance of wheat and ensuring the production level and development speed of wheat in arid areas play a pivotal role in ensuring my country’s food security and the sustainable development of the national economy.Lichen is a symbiotic organism comprised of algae and fungi that can adapt to harsh living environments such as low temperature and drought conditions.The abundant metabolites and genetic resources found in lichens,particularly those genes related to cold tolerance and drought tolerance,have significant development potential.In this study,seven lichen genes were transferred into wheat to obtain overexpression lines.We evaluated the drought tolerance of the overexpression lines and initially screened the lichen gene EpTFIIA,which plays a role in wheat’s drought tolerance.We also identified the drought tolerance of EpTFIIA overexpression wheat lines and studied how its overexpression improves drought tolerance in wheat.The results of this study provide important genetic resources for genetically breeding drought tolerance in wheat.Our main findings are as follows:1.Seven lichen genes were transformed into wheat via an Agrobacterium-mediated genetic transformation system to obtain overexpression positive lines.There are 5,4,6,4,4,3,and 5 positive overexpression wheat lines associated with seven lichen genes Epmbf1,Epann,Ep GST,Ep NDK,Ep SLD,Ep MYB-like and EpTFIIA,respectively.Drought tolerance and statistical survival rate were both analyzed.Experimental results demonstrate that the survival rate of the EpTFIIA overexpression lineis significantly higher than the survival rate of the wild plants.2.Analysis of the expression pattern of EpTFIIA under stress conditions demonstrated that EpTFIIA could participate in several stress responses in Endocarpon pusillum.3.Analysis of subcellular localization and transcriptional activation characteristics demonstrated that EpTFIIA is specifically expressed in the nucleus,while its homologous wheat protein TaTFIIAγ and the homologous Arabidopsis protein AtTFIIA-S are both expressed in the nucleus and the cytoplasm.The lichen EpTFIIA is functionally differentiated from plantTFIIA,while the lichen EpTFIIA,wheat TaTFIIAγ,and Arabidopsis AtTFIIA-S displayed no transcriptional activation activity.4.Following drought treatment,EpTFIIA overexpression lines were more tolerant to drought than wild type plants.The water use efficiency of the overexpression lines is higher than that of the wild type,while the water loss rate and stomata density of the detached leaves and the number of fully opened stomata were both lower than the wild type.Under drought stress conditions,the proline and soluble sugar contents in the EpTFIIA overexpression lines were significantly higher than those of the wild type,while the malondialdehyde content was significantly lower than that of the wild type.5.Luciferase Complementation Assay demonstrated that EpTFIIA and TaTFIIAγ interact with TaTBP1 and TaTBP2 in vivo.