Function Research Glycosyltransferases Genes Of UGT43 And UGT73C1 Involved In Drought And Salt Stress Tolerance In Tomato

Tomato（Lycopersicon esculentum M.）is widely grown and economically valuable.But drought,salinity,flood,and other harsh environment will affect its yield and quality.Drought and salt stress affect plant physiological and biochemical,metabolic pathways,thereby affecting plant growth and development.Glycosyltransferases catalyze glycosylation of small molecules such as plant hormones,secondary metabolites,etc.These substances play important roles in plant growth and physiological activities,and then participate in plant tolerance and resistance to various stresses.However,most of the studies on the response of glycosyltransferase genes to salt and drought stress were concentrated in Arabidopsis,while tomato is rarely reported.Therefore,it is of great significance to explore the role and function of glycosyltransferase in regulating tomato resistance to salt and drought stress.The results of this experiment show that:（1）RT-PCR and Real-Time PCR analysis showed that the expression of Sl UGT73C1 and Sl UGT43 genes in tomatoes increased under salt and drought stress.And Sl UGT73C1 gene expression level was significantly increased.Therefore,the Sl UGT73C1 and Sl UGT43 genes were further studied.（2）Sl UGT73C1 and Sl UGT43 genes were cloned successfully.Bioinformatics analysis showed that the full length of Sl UGT73C1 gene was 1 485 bp,encoding 494 amino acids.In the secondary structure of the protein,α-helix content is the highest.Promoter sequence analysis suggested that the gene might be involved in plant stress response.The full length of Sl UGT43 gene was 1 446 bp,encoding 481 amino acids.The secondary structure of the protein consists of α-helix,β-turn,extended strand,and random coil.Promoter sequence analysis suggested that the gene might be involved in the hormone pathway and regulate plant tolerance to stress.（3）The tissue expression characteristics of Sl UGT73C1 and Sl UGT43 genes were analyzed by Real-Time PCR.Sl UGT73C1 and Sl UGT43 were expressed in all tissues of the tomato.Sl UGT73C1 was highest expressed in flowers,and Sl UGT43 was highest expressed in lateral roots.GUS staining results showed that Sl UGT73C1 was expressed highly in the lateral roots and rosette leaves of A.thaliana,and Sl UGT43 was highly expressed in the stem leaves of A.thaliana.（4）The expression of Sl UGT73C1 and Sl UGT43 genes in tomato leaves and roots under drought stress and salt stress were analyzed.It was found that under the two stress conditions,the expression of the Sl UGT73C1 gene in leaves and roots was first increased and then decreased.The expression trend of the Sl UGT43 gene in leaves under salt and drought stress and roots under drought stress was the same as that of the Sl UGT73C1 gene,while the expression trend in roots under salt stress was just the opposite.GUS staining showed that the expression of the Sl UGT43 gene in Arabidopsis increased under salt and drought stress.（5）Plant overexpression vectors of Sl UGT73C1 and Sl UGT43 genes were successfully constructed and transgenic plants were obtained.Under salt and drought stress,it was found that the phenotypes of germination and root length of Arabidopsis plants overexpressing Sl UGT73C1 and Sl UGT43 genes were not significantly different from those of wild type,but the germination rate,SOD,and POD activities were higher than the wild type,and the MDA content was lower than the wild type.The expression levels of Marker genes COR15,KIN1,SOS1,NHX1,and RD22 A under salt stress and Marker genes NCED3,RD29 A,P5CS,and COR47 under drought stress were all increased in transgenic plants,which were significantly higher than those in wild-type.It was suggested that Sl UGT73C1 and Sl UGT43 genes might regulate plant tolerance to salt and drought stress through the antioxidant system and induction of related Marker gene expression,and the response to drought stress might depend on the ABA pathway.