Abstract: 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.

Key words: potato bacterial wilt, RACE, StPI gene, full-length cDNA, gene expression