丹参SmPI1和SmPI2基因克隆及胁迫表达研究

Clone and Expression of SmPI1 and SmPI2 from Salvia miltiorrhiza under Stress

该研究从药用植物丹参中克隆了SmPI1和SmPI2蛋白酶抑制剂基因,采用生物信息学和实时荧光定量PCR方法对其序列及表达模式进行了分析。序列分析结果表明,丹参SmPI1和SmPI2基因分别含有一个长度为222bp和216bp的开放阅读框,编码73和71个氨基酸;2个编码蛋白都无跨膜结构域和信号肽,预测都定位于细胞质中;SmPI1和SmPI2蛋白与川桑、可可、苜蓿等植物的蛋白酶抑制剂基因相似性较高,分别为58%、52%、53%和54%、56%、51%。实时荧光定量PCR结果表明,SmPI1和SmPI2基因受茉莉酸甲酯(MeJA)和甘蓝黑腐病黄单胞菌(Xanthomonas campestris pv.Campestris,XC)显著诱导,说明丹参SmPI1和SmPI2基因可强烈响应这两类胁迫,可能参与丹参中两类胁迫分子途径相关的抗性反应。

Proteinase inhibitors are one group of small proteins associated with the resistance of plants. We cloned two protease inhibitor genes（SmPI1 and SmPI2） from Salvia miltiorrhiza, and then analyzed the sequence characterizations using the bioinformatics methods and their expression patterns by real-time qPCR. The result shows that the completed ORFs of SrnPI1 and SrnPI2 are 222 bp and 216 bp in length, encoding 73 and 71 amino acids,respectively. SmPI1 and SmPI2 may be located in cytoplasm without trans- membrane domain and signal peptide by prediction using bioinformatics methods. Amino acid sequences of SmPI1 and SmPI2 showed high homology to proteinase inhibitors from Morus notabilis, Theobroma cacao and Medicago truncatula. Quantitative PCR analysis showed that the expression of SmPI1 and SmPI2 were significantly induced under the treatment of methyl jasmonate（MeJA） or Xanthomonas campestris pv. Campestris（XC）. This indicated that the protease inhibitor gene SmPI1 and SmPI2 could response to this two stress signals, and may be closely related to the resistance of S. miltiorrhiza.