Abstract: A cDNA library, enriched with full-length resistance-related genes, was constructed by
SMART ( Switching mechanism at 5′end of RNA transcrip t) technique using dip loid potato leaves infected
with race 3 (Biovar 2) PO41 of Ralston ia solanacearum for 24 h and 48 h. A full2length cDNA of DnaJ-like
homolog with comp leted open reading frame of 177 amino acids was cloned from potato using the strategy of
RACE ( rapidamp lification of cDNA ends) combined with cDNA library. This cDNA homologwas designated
as S tDnaJ , which contains 735 bp with an un-translated region of 25 bp at its 5′end and a polyA tail at the 3′
end (GenBank accession number: DQ885360). BLAST search against NCBI showed that the S tDnaJ gene
shared 84% identity with DnaJ-like 20 of A rabidopsis thaliana in nucleotide and 59% in amino acid, but no
similar genes have been reported from potatoes in the NCBI database. Analysis of semi-quantitative RT-PCR
indicated that this gene was induced by Ralston ia solanacea rum as well as up-regulated by jasmonic acid
(JA). That suggests S tDnaJ gene mayplay a role in recovering the activity of p rotein destroyed by R. so
lanacearum or Jasmonic acid (JA) stress.

Key words: Potato, cDNA library, RACE, DnaJ-like gene