Analysis Of Raffinose Synthase Gene Family In Wheat And Identification Of Drought Resistance And Salt Tolerance Function Of TaRS15-3B

Wheat(Triticum aestivum L.)is one of the widely cultivated food crops in the world,but its yield and quality suffer losses due to the adverse effects of environmental pressures such as drought,high salinity,high and low temperature,and the attack of pathogens and pests.Therefore,the discovery of candidate genes in response to stress in wheat is an urgent problem in wheat production.Relevant studies have shown that raffinose synthase(RS)participates in a variety of biological processes and plays a crucial role in plant growth and development,response to biotic and abiotic stresses.However,its research in wheat is rarely reported.Therefore,this study used bioinformatics methods to screen and identify the raffinose synthase gene family of wheat based on wheat genome information,and analyzed its physical and chemical properties,phylogenetic and evolutionary relationships,conserved domains,promoter cis acting elements,and expression patterns.On this basis,the drought resistance and salt tolerance functions of the screened candidate gene TaRS15-3B in wheat germination stage,seedling stage and the middle and late stages of growth and development were evaluated.The main research results are as follows:1.A total of 34 genes encoding raffinose synthase were screened from the wheat genome,all of which have conserved domains Raffinose＿Syn(PF05691),which can be divided into four subfamilies.The RS gene family of wheat has more collinear blocks with the monocotyledonous plant Aegilops tauschii,and the evolutionary relationship is closer,indicating that the RS protein is conserved in the process of species evolution,and the RS gene family in wheat may be derived from the polyploidization process of wheat.2.The results of cis acting element analysis,go enrichment analysis and interaction protein prediction of wheat RS gene family showed that the wheat RS gene family directly or indirectly participated in sugar metabolism in plants through ABA and Me JA signal transduction pathways,thus further responding to abiotic stresses in plants.There are differences in protein motifs,cis acting elements,chromosomal localization and expression levels in different tissues and abiotic stresses of wheat among subfamilies of RS gene family,indicating that each subfamily performs different functions.3.TaRS13-3A、TaRS15-3B and TaRS17-3D on chromosome 3 of wheat RS Ⅲ subfamily have specific expression patterns,and their protein similarities are as high as 98.38%.The expression of TaRS15-3B gene was relatively high in leaves and seeds,and was up-regulated under drought,salt,ABA and Me JA treatments.4.TaRS15-3B gene was constructed into p WMB003 vector,and the callus of wheat variety Kenong 199 was bombarded by gene gun to obtain T3 generation of wheat overexpressing TaRS15-3B.It was found that the proline content,CAT activity,SOD activity and POD activity of wheat overexpressing TaRS15-3B increased significantly under drought and salt stress.TaRS15-3B gene could enhance the tolerance of transgenic wheat to drought and salt stress at germination stage,seedling stage and mid late development stage.5.The silencing of TaRS15-3B gene mediated by BSMV will lead to the sensitivity of wheat seedlings to drought and salt stress,and reduce the expression levels of wheat plant stress-related genes(TaP5CS、TaLEA7、TaDREB1)and ROS scavenging system related genes(TaPOD、TaSOD1、TaCAT3),thus further affecting the ability of wheat to cope with drought and salt stress.In summary,this study revealed the important role of wheat RS gene family in plant response to abiotic stress.TaRS15-3B gene can improve the tolerance of transgenic wheat to drought and salt stress,and provide direction for the research of other wheat RS gene families,as well as candidate genes for developing stress resistant molecular breeding of wheat.