title: Lipid transfer proteins (nsLTPs) from barley and maize leaves are potent inhibitors of bacterial and fungal plant pathogens.
abstract: Four homogeneous proteins (Cw18, Cw20, Cw21, Cw22) were isolated from etiolated barley leaves by extraction of the insoluble pellet from a Tris-HCl (pH 7.5) homogenate with 1.5 M LiCl and fractionation by reverse-phase high-performance liquid chromatography. All 4 proteins inhibited growth of the pathogen Clavibacter michiganensis subsp. sepedonicus (EC50s = 1-3 x 10(-7) M) and had closely related N-terminal amino acid sequences. The complete amino acid sequences of proteins Cw18 and Cw21 were determined and found to be homologous to previously described, non-specific lipid transfer proteins from plants (32-62% identical positions). The proteins also inhibited growth of the bacterial pathogen Pseudomonas solanacearum (EC50s = 3-6 x 10(-7) M) and the fungus Fusarium solani (EC50s = 3-20 x 10(-6) M). A homologous protein from maize leaves (Cw41) was purified in a similar manner and also found to have inhibitory properties. A synergistic effect against the fungus was observed when protein Cw21 was combined with thionins. A defense role for non-specific lipid transfer proteins from plants is proposed.
authors.affiliation: Laboratorio de Bioquímica y Biología Molecular, ETS Ingenieros Agrónomos-UPM, Madrid, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Molina
authors.forename: A
authors.initials: A
authors.lastname: Segura
authors.forename: F
authors.initials: F
authors.lastname: García-Olmedo
mesh_terms: D000595:Amino Acid Sequence; D000890:Anti-Infective Agents / Q000302:isolation & purification / Q000494:pharmacology*; D000935:Antifungal Agents / Q000302:isolation & purification / Q000494:pharmacology*; D052179:Antigens, Plant; D002352:Carrier Proteins / Q000737:chemistry / Q000494:pharmacology*; D001467:Hordeum / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry / Q000494:pharmacology*; D017386:Sequence Homology, Amino Acid; D003313:Zea mays / Q000737:chemistry*
chemical_list: D000890:Anti-Infective Agents; D000935:Antifungal Agents; D052179:Antigens, Plant; D002352:Carrier Proteins; D010940:Plant Proteins; C511920:lipid transfer proteins, plant