Expression of recombinant human lactoferrin in transgenic alfalfa plants

In order to produce human lactoferrin (Lf) in alfalfa (Medicago sativa L.), a construct containing human Lf cDNA under the control of cauliflower mosaic virus 35S promoter was engineered. As selectable marker bar gene, whose expression in plant cells confers tolerance to L-phosphinothricin (ppt) was used. Plants from a highly embryogenic alfalfa clone from the Bulgarian cultivar Obnova 10 were transformed using Agrobacterium tumefaciens mediated leaf disc method. Transgenic alfalfa plants were established from ppt-resistant calli via indirect somatic embryogenesis. The presence of human Lf cDNA in the genome of the selected regenerants was confirmed by polymerase chain reaction (PCR). Reverse transcriptase (RT)-PCR and Western blot showed expression of human Lf in leaf tissue. Studies on antibacterial effect of the recombinant glycoprotein were conducted and resistance of the transgenic alfalfa plants to two phytopathogens, Pseudomonas syringae pv. syringae and Clavibacter michiganensis, was demonstrated. The obtained results suggest that the expression of human Lf in alfalfa could be beneficial not only for producing recombinant protein for clinical application but also for crop quality improvement.