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丹参EST序列的Blast分析表明,一条序列与硫堇(thionin,THI)基因有较高的同源性,该序列长575bp,包含1个长366bp的开放阅读框(ORF),编码121个氨基酸,命名为SmTHI,GenBank登陆号为DQ212984。在此基础上设计引物,分别从cDNA和gDNA水平上克隆到该基因的全编码区序列的结果表明,该基因无内含子。序列分析表明,该编码蛋白与大多数植物的THI蛋白前体高度同源,并符合植物硫堇类蛋白的序列模式和特征:C-C-X(5)-R-X(2)-[FY]-X(2)-C,N端具17个氨基酸的信号肽,中间46个氨基酸为成熟THI部分,C端的58个氨基酸为酸性多肽部分。成熟的THI蛋白带正电荷,偏碱性,推测可能有抗病原微生物活性。实时定量PCR检测SmTHI在丹参不同组织部位的表达以及在黄瓜细菌性角斑病菌(PSL)、NaCl和水杨酸(SA)溶液诱导下的表达结果表明:SmTHI在植物的根、茎和叶中均有不同程度的表达,其表达丰度为叶>茎>根;在PSL、NaCl和SA溶液诱导下该基因的表达呈上调趋势。
Blast analysis of the Salvia miltiorrhiza EST sequence showed that a sequence has a high homology with thionin (THI) gene, which is 575 bp in length and contains an open reading frame (ORF) of 366 bp encoding a polypeptide of 121 amino acids, Named SmTHI, GenBank accession number is DQ212984. Based on this, the primers were designed and cloned into the full coding region of the gene at the cDNA and gDNA levels, respectively. The results showed that the gene had no introns. Sequence analysis showed that the encoded protein was highly homologous to THI protein precursors of most plants and conformed to the sequence patterns and characteristics of plant thionine proteins: CCX (5) -RX (2) - [FY] -X (2 ) -C, a 17 amino acid signal peptide at the N terminus. The middle 46 amino acids are the mature THI part and the 58 amino acids at the C terminal are the acidic polypeptide part. The mature THI protein is positively charged and alkaline, presumably resistant to pathogenic microorganisms. The expression of SmTHI in different tissue parts of Salvia miltiorrhiza and its induction by Cucumber bacterial cori hydoriae (PSL), NaCl and salicylic acid (SA) solution were detected by real-time PCR. The results showed that SmTHI was expressed in the roots, stems and leaves of plants The expression abundance was leaf> stem> root. The expression of this gene was up-regulated under the induction of PSL, NaCl and SA solution.