Isolation and characterization of a new mannose-binding lectin gene from Taxus media.

In this paper, we report the cloning and characterization of the first mannose-binding lectin gene from a gymnosperm plant species, Taxus media. The full-length cDNA of T. media agglutinin (TMA) consisted of 676 bp and contained a 432 bp open reading frame (ORF) encoding a 144 amino acid protein. Comparative analysis showed that TMA had high homology with many previously reported plant mannose-binding lectins and that tma encoded a precursor lectin with a 26-aa signal peptide. Molecular modelling revealed that TMA was a new mannosebinding lectin with three typical mannose-binding boxes like lectins from species of angiosperms. Tissue expression pattern analyses revealed that tma is expressed in a tissue-specific manner in leaves and stems, but not in fruits and roots. Phylogenetic tree analyses showed that TMA belonged to the structurally and evolutionarily closely related monocot mannose-binding lectin superfamily. This study provides useful information to understand the molecular evolution of plant lectins.