Cloning And Functional Analysis Of Xyloglucan Endotransglucosylase Gene BvXTH1 From Sugar Beets (Beta Vulgaris L)

Xyloglucan glycoside transfer is a key enzyme in the process of plant cell wall remodeling.It promotes cell elongation by increasing the malleability of the cell wall,thereby affecting plant growth and development.In order to study the relationship between the XTH gene and the root growth of sugar beet,the BvXTH1 gene was cloned and screened using the beet line BS02 developed by the Institute of beet Physiology,Inner Mongolia Agricultural University.The results were as follows:1?The coding region of the BvXTH1 gene is 876 bp.The protein molecular mass is31782.26Da,and the chemical formula is C₁₄₁₇H₂₁₁₃N₃₈₁O₄₃₆S₁₀.The isoelectric point/pI of the BvXTH1 protein is 5.04,which is weakly acidic and the hydrophobicity average coefficient is-0.357.It is predicted that the protein may be a hydrophilic protein.Sequence analysis showed that the XTH family conserved motif DEIDFEFLG exists in the BvXTH1protein.SignalP 4.1 Server analysis showed that BvXTH1 contains a signal peptide.Transmembrane structure predictions indicate that there is a transmembrane helix at the N-terminus of BvXTH1.Phylogenetic tree analysis concluded that BvXTH1 is closely related to Chenopodium quinoa and Spinacia oleracea.2?The expression trends of BvXTH1 gene in different organs of sugar beet were leaf>stalk>root,and the high-yield cultivar was higher than high sugar cultivar.3?A plant overexpression vector pCAMBIA1300-BvXTH1 was constructed and transformed into Arabidopsis thaliana to obtain three transgenic lines.4?The XTH enzyme activity of the transgenic lines was significantly higher than that of the WT,and increased with the increase of gene expression levels;the fresh weight,root length,and cell size of the root elongation zone of the transgenic lines were significantly greater than that of the WT;exogenous spraying of rapastrolactone can promote the expression of BvXTH1 gene and enhance the activity of XTH enzyme.5?Under drought conditions,the leaf size and root length of WT were smaller than those of the transgenic lines;AtSOD1,AtPOD1 genes related to the antioxidant system,AtP5CS1,the key gene for proline synthesis were found in the transgenic plants.The expression level was significantly higher than that of WT.BvXTH1 gene could increase the resistance of Arabidopsis thaliana.