大豆(Glycine max (L.) Merr.)植酸酶基因Sphy1 的鉴定及其分子特征研究

novel phytase gene Sphy1 was isolated based on screening a cDNA library which was constructed from germinated soybean (Glycine max (L.) Merr. cv. Kefeng6) cotyledon. The full-length cDNA of Sphy1 was 1 644 bp predicated to encode 547 amino acids including an N terminal signal peptide of 27 amino acids. Phylogenetic analysis indicated that Sphy1 had high similarities with the phytase genes from M. truncatula and rice, and acid phosphatase genes from M. truncatula and Arabidopsis. Prokaryotic expression of Sphy1 in BL21 showed that the induced protein had high phytase activities. The transcripts of Sphy1 could be detected in various tissues, such as cotyledons, leaves, stems and roots of seedlings. The phytase activities in the above tissues were accordance with their corresponding Sphy1 transcripts. The transcripts of Sphy1 in cotyledons showed an increasing trend from 5 to 30 days after germination, suggesting that Sphy1 had involved the hydrolyses of the organic phosphorus compounds in seeds from the stages of early seed germination to young seedlings in soybean. Therefore, it is speculated that Sphy1 plays an important role during the seed germination and the growth of the seedlings by releasing inorganic phosphorus (Pi) from phosphorus reserve in seeds.