Molecular cloning of a new lectin gene from Z. grandiflora.

Using RNA extracted from Zephyrathes grandiflora young leaves and primers designed according to the conservative regions of Amaryllidaceae lectins, the full-length cDNA of Z. grandiflora agglutinin (ZGA) was cloned by rapid amplification of cDNA ends (RACE). The full-length cDNA of ZGA was 934 bp and contained a 576 bp open reading frame (ORF) encoding a 191 amino acid protein. Through comparative analysis of zga gene and its deduced amino acid sequence with those of other Amaryllidaceae species, it was found that zga encoded a precursor lectin with signal peptide. Molecular modeling suggested that ZGA was a mannose-binding lectin with three mannose-binding sites like lectins from other Amaryllidaceae species. Southern blot analysis of the genomic DNA revealed that zga belonged to a multi-copy gene family like those of many other Amaryllidaceae species such as Galanthus nivalis and Clivia miniata.