马铃薯蛋白酶抑制子StPI基因的克隆及表达分析

 【目的】克隆马铃薯蛋白酶抑制子基因StPI的全长cDNA。【方法】以马铃薯高抗青枯病二倍体基因型ED13为材料，采用RACE方法进行StPI基因全长cDNA的克隆，利用半定量RT-PCR方法进行该基因的诱导表达分析。【结果】获得了StPI基因的全长cDNA，序列分析表明：该基因具有完整的开放阅读框架，编码116个氨基酸，与马铃薯蛋白酶抑制子 I 前体具有较高的同源性（核苷酸和氨基酸序列同源性分别为89%和74%）。该基因同时受青枯病菌的诱导和茉莉酸的调节，在6～12 h内即达到最高表达水平，但二者又有明显不同。相对而言，StPI基因受青枯病菌的诱导较弱，而受茉莉酸（JA）的诱导较为强烈，在JA处理3 h表达量即明显升高，6～12 h迅速升至最高。【结论】本研究从马铃薯抗青枯病基因型ED13中获得了StPI基因的全长cDNA。该基因可能参与了马铃薯的抗青枯病反应，且病菌处理对该基因的诱导可能与JA刺激具有相似或相同的信号途径。

Cloning and Expression Analysis of Proteinase Inhibitor Gene StPI in Diploid Potato

A full-length cDNA of proteinase inhibitor (PI) homolog with completed open reading frame of 116 amino acids was cloned from Ralstonia solanacearum resistant potato leaves using rapid amplification of cDNA ends (RACE) method and designated as StPI. BLAST search against NCBI showed that the StPI gene shared 89% identity with potato proteinase inhibitor I precursor in nucleotide and 74% in amino acid. Analysis of semi-quantity RT-PCR indicated that this gene was induced by Ralstonia solanacearum as well as up-regulated by jasmonic acid (JA), and its expression reached the highest level before 12h post R. solanacearum inoculation or JA-treatment, then leveled off. Moreover, this gene was strongly induced by JA and its mRNA accumulation quantity increased quickly post JA treatment. It concludes that StPI gene may play a role in potato resistance against R. solanacearum. and the inducyion of StPI by R. solanacearum invasion may have a similar signal transduction pathway with JA treatment.