Expression of a human lactoferrin cDNA in tobacco cells produces antibacterial protein(s).

A suspension tobacco (Nicotiana tabacum L.) cell line was transformed to express human lactoferrin, an iron-binding glycoprotein. The transgenic calli produced a protein that was significantly smaller than the full-length lactoferrin protein. Total protein extracts made from transgenic tobacco callus exhibited much higher antibacterial activity than commercially available purified lactoferrin as determined by the decrease of colony-forming units when tested with four phytopathogenic species of bacteria. Introduction of the lactoferrin gene in crop plants may provide resistance against phytopathogenic bacteria.