Using a wheat purple acid phosphatase (PAP)-type phytase gene referred to PAPhya1 as a query, a novel phytase gene to be homologous to PAPhya1 that has not been characterized and functionally analyzed was identified and designated as TaPHYl in this study. The full length of TaPHY1 is 1771 bp, encoding a 548-aa polypeptide. TaPHY1 contains three conserved signature domains generally identified in PAP-type phytases, including metal-lophos, purple acid phosphatase and metallo-dependent phosphatases. Phylogenetic analysis revealed that TaPHY1 shares high similarities to the previously reported phyase genes such as PAPhya1~PAPPhya3 and PAPhyb1 ~PAPhyb2, as well as high similarities to PAP-type phytase genes in other plant species including the barley (H. Vulgare) and rye (S. Cereale).TaPHY1 is abundantly expressed in germinating seed and little expressed in the primary roots and leaves. The expressed TaPHY1 based on the prokaryotic expression system exhibited strong capability to degrade the phytate, a major component of organic phosphate compound in the mature seed. Taken together, as a novel PAP-type phytase gene in wheat, TaPHY1 plays crucial roles on degradation of the seed phytic acid and its derivatives, and provides the Pi for the novel organs of the young seedlings.%利用小麦植酸酶基因PAPhya1进行同源查找,获得1个与该基因高度同源、尚未开展分子特征和生物学功能研究的小麦新型植酸酶基因TaPHY1.TaPHY1的全长cDNA序列为1771 bp,编码548个氨基酸残基,TaPHY1含有紫色酸性磷酸酶(PAP)类植酸酶通常含有的保守域Metallophos、Purple acid phosphatase和Metallo-dependent phosphatases.系统进化分析表明,TaPHY1除与已报道的小麦PAP类植酸酶基因PAPhya1～PAPPhya3和PAPh yb1～PAPh yb2高度同源外,还与部分大麦和黑麦的PAP型植酸酶基因在序列上高度相似.TaPHY1在萌发种子中呈高丰度表达,而在根叶中的表达水平很低.对原核表达系统中表达的TaPHY1研究发现,该蛋白在体外具有较强分解有机态磷植酸盐的能力.因此,TaPHY1是小麦中归属于PAP类别的一个新型植酸酶基因,在种子萌发及幼苗生长早期降解种子内贮存的植酸及其盐类、释放新生器官所需的磷素中发挥着重要作用.
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