丹参中病程相关蛋白基因SmSTH-2的生物信息学分析

Pathogenesis-Bioinformatics Analysis of Pathogenesis-related Protein Gene SmSTH-2 in Salvia miltiorrhiza Bge.

对丹参cDNA文库的表达序列标签(EST)序列进行BLAST分析显示,其中一条序列与病程相关蛋白基因STH-2有较高的同源性。该序列全长691bp,包含1个长483bp的开放阅读框(ORF),编码160个氨基酸,命名为SmSTH-2。生物信息学分析显示:SmSTH-2所编码蛋白的分子质量为17990Da,等电点为5.15,富含谷氨酸、赖氨酸、甘氨酸、丝氨酸,无信号肽,属于稳定类蛋白。与NCBI注册的其他6种植物来源的病程相关蛋白基因编码的氨基酸序列的同源性在42%～46%之间。实时荧光定量PCR的方法检测丹参不同组织部位中SmSTH-2表达和病原菌对该基因诱导表达的影响的结果表明:SmSTH-2在植物的根、茎、叶中均有不同程度的表达,其表达丰度为根>叶>茎;丹参叶片接种黄瓜细菌性角斑病病原菌后,4d内可诱导该基因的表达量持续增加。用PCR方法从基因组水平克隆到SmSTH-2的DNA序列,测序表明SmSTH-2的编码序列在DNA水平上含有一个71bp的内含子,DNA序列注册号为EF621486.

cDNA library of Salvia miltiorrhiza was constructed. All the sequences of expressed sequence tags （EST） were analyzed by BLAST approach of NCBI. One of these sequences which showed high homology with pathogenesis-related protein STH-2 was found. The sequence is 691 bp, containing a 483 bp open reading frame （ORF） and encoding 160 amino acid-peptide, and is named SmSTH-2. Bioinformatics analysis showed that the calculated molecular mass is 17 990 Da, theoretical isoelectric point is 5.15, the deduced amino acids are rich in glutamic acid, lysine, glycin and serine; STH-2 is a stable protein without signal peptide. Amino acid homology of the SmSTH-2 compared with those submitted to NCBI in other six plants ranged from 42% to 46%. Real-time fluorescent quantitative PCR was used to detect the expression of SmSTH-2 in different organs of S. miltiorrhiza and different time on pathogen inoculation. The result showed that the expression of SmSTH-2 is the most abundant in root, followed by in leaf, and the least in stem. The expression of SmSTH-2 increased within 4 d after pathogen inoculation. Meanwhile, the DNA sequence of the STH-2 was cloned by PCR and the result showed that there is a 71 bp intron in the encoding region. GenBank accession number of the DNA sequence is EF621486.