Abstract：Wheat (Triticum aestivum) is one of the important food crops in China. However, drought and other adverse conditions have seriously affected the quality and yield of wheat.Screening of stress-resistant genes and analyzing their mechanism of action can provide candidate genes and theoretical basis for wheat resistance molecular breeding. Xyloglucan endotransglucosylase/hydrolase (XET/XEH) is a class of enzymes with xyloglucan endoglycosyltransferase /hydrolase activity, which are collectively referred to as XTH, belonging to glycoside hydrolase 16 (GH 16) family. It can participate in the formation and remodeling of cell wall and plays an important role in plant growth and development and stress resistance. In this study, the cDNA sequence of the TaXTH-7A gene (GenBank No. MK395550) was isolated by PCR from wheat, and the coding region was 870 bp in length, which encoded 290 amino acid. The TaXTH-7A genome contained 3 exons and 2 introns. Protein sequence analysis indicated that TaXTH-7A contains several XET-specific domains and they were highly conserved across species. Phylogenetic tree analysis indicated that the XTH-7A protein evolved between monocotyledonous and dicotyledonous, and between C3 and C4 plants, and was closely related to Aegilops tauschii. The results of qRT-PCR showed that TaXTH-7A gene was expressed in roots, stems, leaves and spiket of wheat at heading stage, and it was dominant in roots. After drought stress, its expression increased and peaked at 4 hours. Subcellular localization results showed that TaXTH-7A was localized in the cytoplasm, cell membrane, and apoplast. Functional identification showed that over-expression of tTaXTH-7A enhanced drought resistance of Arabidopsis thaliana. This study is helpful to further study the function of TaXTH-7A gene in wheat, and also provides a theoretical basis for wheat resistance to abiotic stress.
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