A suspension tobacco (Nicotiana tabacum 1.) cell line was trans-
formed to express human ladoferrin, an iron-binding glycoprotein.
The transgenic calli produced a protein that was significantly
smaller than the full-length lactoferrin protein. Total protein ex-
tracts made from transgenic tobacco callus exhibited much higher
antibacterial activity than,commercially available purified lacto-
ferrin as determined by the decrease of colony-forming units when
tested with four phytopathogenic species of bacteria. Introduction
of the ladoferrin gene in crop plants may provide resistance against
phytopathogenic bacteria.