Molecular Cloning and Expression of a Novel Gene Related to Legume Lectin from <i>Salvia miltiorrhiza</i> Bunge

Abstract

Lectins have been well studied and proved to play important roles in plant defense but information of legume lectins from non-legume plants has been rarely reported. A new legume lectin gene, designated as SmL1, was cloned from Salvia miltiorrhiza Bunge, a famous traditional Chinese medicinal plant. The cDNA of SmL1 was 919 bp in length and contained an 822 bp open reading frame (ORF) encoding a putative lectin precursor with two legume lectin domains. The deduced SML1 protein of SmL1 shared 29 to 43% identities with other legume lectin sequences. Real time PCR analysis revealed that SmL1 was predominantly expressed in the leaves and could be induced by pathogens and MeJA. The recombinant protein (rSmL1) of SmL1 in Escherichia coli M15 was purified and showed agglutination activity towards rabbit and mouse red blood cells, and anti-bacterial activity against E. coli (ATCC35218), Pseudomonas lachrymans (PSL) and Xanthomonas campestris pv. Campestris (Pammel) Dowson (XC-1). Based on these results, SmL1 could play a role in medicinal plant disease control.

Keywords: Anti-Bacterial Activity, Gene Expression, Legume Lectin, Recombinant Protein, Salvia miltiorrhiza Bunge