Abstract:Type Ⅰ allergic reaction results from the cross-binding of major allergen protein and IgE antibodies. A novel allergen gene (Sam a1) from Salvia miltiorrhiza Bunge was cloned, which contained an ORF with 483 bp and coded 166 amino acid residues. It contained a Bet v1 protein domain, shared 66％ identical to mal d1-a major allergen protein from apple. The 3-D model suggested the deduced protein contained an extended C-terminal alpha helix containing a major T cell epitope. The real time PCR results indicated Sam a1 was induced by PSL and NaCl, Sam a1 may be involved in pathogenesis infection and stress by NaCl. The gene was expressed in E.coli M15, and a target protein was obtained. In addition, the recombinant protein was expressed in large quantities after 5~7 h induced by IPTG. This research laid the groundwork for the study of allergic reaction mechanism in plant at molecular level, especially for the development of Chinese herb medicine.