EN
A full-length cDNA, SmPR10-1, encoding a pathogenesis-related class 10 protein, was isolated from Salvia miltiorrhiza, a well-known Chinese herbal plant. From the coding region of nucleotide sequence, the amino acid sequence can be predicted which contained conserved domain (K–A–X–E–X–Y) in the C-terminal helix found in most members of the PR10 protein family. Phylogenetic tree analysis indicated that the SmPR10-1 protein showed a sequence similarity which was much higher to dicot proteins than to other PR10 proteins. Prokaryotic expression of SmPR10-1 protein in fusion with a His-tag produced a 22 kDa protein in E. coli BL21 (DE3), which exhibited ribonuclease activity in vitro. The purified protein was used to assay antifungal activity and the results showed SmPR10-1 only inhibited the growth of Phytophthora infestans. The RT-PCR results showed that the SmPR10-1 was expressed in high transcript level in leaves, stalks and low levels in roots. This protein seems to involve in the plant active defense response through activation of the methyl jasmonate signaling pathway rather than salicylic acid or abscisic acid pathway.