Functional Characterization of a new Lipid Transfer Protein With Antimicrobial Properties From Medicago truncatula

Non specific lipid transfer proteins form a multigenic protein family in plants. They are able to bind in vitro different lipids but their function in vivo remains speculative. They have been suggested to participate to many aspects of plant physiology and cell biology, including assembly of extracellular hydrophobic polymers and involvement in stress and pathogen responses. To understand whether MtN5, a new LTP2 identified in Medicago truncatula roots, plays a possible role in the plant protection function, we investigated its antifungal and antibacterial properties. A cDNA sequence encoding the protein, without the signal peptide, was cloned in a prokaryotic expression system. The purified recombinant protein has been characterized for its lipid binding properties and for its in vitro antimicrobial properties. The results showed that the recombinant MtN5 is able to bind lipids, similarly to other members of the LTP protein family and possesses a selective action against specific pathogens, potentially due to interactions with microbe specific membrane structures.