Identification,Evolution And Functional Analysis Of SnRK Gene Family In Wheat

As the second largest grain crop of China,wheat has an important position in agricultural production.The abiotic stresses such as salt and drought and the biological stresses such as Fusarium graminearum and powdery mildew are the main factors restricting the sustainable development of wheat.Mining genes related to biological and abiotic stress resistance in wheat can enrich the resource pool of wheat stress resistance breeding.SnRK,which is a Ser/Thr protein kinase,regulates target proteins through phosphorylation and plays an important role in stress response by coordinating information exchange between multiple physiological signaling pathways in plants.Although there are comprehensive identification and related research of SnRK gene family in Arabidopsis and rice,but the family has never been systematically studied in wheat.Using bioinformatics methods,the 149,37,84 and 50 genes were identified from bread wheat,Triticum urartu,Aegilops tauschii,and Triticum dicoccoides.And the protein characteristics,gene expansion mechanism and evolutionary relationship of SnRK from four species were analyzed.Then,the expression pattern of wheat SnRK gene and the protein interaction network were analyzed.The role of TaSnRK2.4-B in wheat response to ABA stress was mainly studied.The main research results are as follows:1.Combining BLAST and HMM,186 amino acid sequences,62 amino acid sequences,317 amino acid sequences and 252 amino acid sequences were identified from bread wheat,Triticum urartu,Aegilops tauschii,and Triticum dicoccoides.According to the homology and structural characteristics of protein sequences,the SnRK gene families in these four species can be divided into three subfamilies(SnRK1,2 and 3).Analysis of the gene structure,protein characteristics and cis-acting element in the promoter showed that the gene sequence and protein sequence belong to one subfamily was conserved and the function was relatively stable.2.Chromosome localization,collinear analysis and Ka/Ks analysis indicated that genome-wide replication events and segment duplication events were the main mechanisms of wheat SnRK gene family expansion.The majority of SnRK homologous genes between wheat and its sub-genome donor species underwent purification selection to maintain the conservation and stability of gene function.At the same time,we also found that a few SnRK genes were positively selected,suggesting that some genes were evolving new functions through rapid mutation to adapt to the change of living environment.3.The results of transcriptome analysis,GO annotation,KEGG and PPI network indicate that TaSnRK family is widely involved in growth and development,stress resistance and other biological processes.4.Based on the classification of TaSnRK genes and the results of transcriptome expression profile analysis,three genes were selected from three subfamilies,respectively.The expression patterns of these nine genes under PEG,Na Cl and high ABA stress,as well as under the infection of wheat powdery mildew and Fusarium graminearum were studied by q RT-PCR.The results showed that the differential expression of TaSnRK2.4-B and TaSnRK3.16-D was more significant and the expression profile was wider5.Subcellular localization analysis showed that TaSnRK2.4-B was localized in the cytoplasm and nucleus of the cell membrane,and TaSnRK3.16-D was localized in the cell membrane.Over-expression of TaSnRK2.4-B and TaSnRK3.16-D can improve the resistance of tobacco leaves to P.infestans and inhibit infection,and TaSnRK2.4-B has a more significant inhibitory effect than TaSnRK3.16-D.The q RT-PCR analysis showed that ABA treatment could simultaneously induce the up-regulated expression of Ta SCS and downstream TaSnRK2.4-B in wheat.In conclusion,in this study,analysis of SnRK gene family in wheat and its sub-genome donor wheat from the whole genome was carried out,which filled the blank of the study on the evolutionary expansion mechanism of SnRK gene in wheat and enriched the theoretical basis for the study on the evolution process of wheat.The expression profile of wheat SnRK gene was analyzed,and some genes valuable for further study in biological and abiotic stress were obtained.The mechanism of TaSnRK2.4-B gene was explored and preliminarily verified,which laid a certain foundation for further study on the mechanism of wheat SnRK gene response to abiotic stress.