title: A maritime pine antimicrobial peptide involved in ammonium nutrition.
abstract: A large family of small cysteine-rich antimicrobial peptides (AMPs) is involved in the innate defence of plants against pathogens. Recently, it has been shown that AMPs may also play important roles in plant growth and development. In previous work, we have identified a gene of the AMP β-barrelin family that was differentially regulated in the roots of maritime pine (Pinus pinaster Ait.) in response to changes in ammonium nutrition. Here, we present the molecular characterization of two AMP genes, PpAMP1 and PpAMP2, showing different molecular structure and physicochemical properties. PpAMP1 and PpAMP2 displayed different expression patterns in maritime pine seedlings and adult trees. Furthermore, our expression analyses indicate that PpAMP1 is the major form of AMP in the tree, and its relative abundance is regulated by ammonium availability. In contrast, PpAMP2 is expressed at much lower levels and it is not regulated by ammonium. To gain new insights into the function of PpAMP1, we over-expressed the recombinant protein in Escherichia coli and demonstrated that PpAMP1 strongly inhibited yeast growth, indicating that it exhibits antimicrobial activity. We have also found that PpAMP1 alters ammonium uptake, suggesting that it is involved in the regulation of ammonium ion flux into pine roots.
authors.affiliation: Departamento de Biología Molecular y Bioquímica, Instituto Andaluz de Biotecnología, Campus Universitario de Teatinos, Universidad de Málaga, 29071-Málaga, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Canales
authors.forename: Concepción
authors.initials: C
authors.lastname: Avila
authors.forename: Francisco M
authors.initials: FM
authors.lastname: Cánovas
mesh_terms: D000595:Amino Acid Sequence; D000890:Anti-Infective Agents / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001692:Biological Transport; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D008958:Models, Molecular; D010802:Phylogeny; D041605:Pinus sylvestris / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000378:metabolism*; D018749:RNA, Plant / Q000235:genetics; D011994:Recombinant Proteins; D036226:Seedlings / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D014197:Trees / Q000235:genetics / Q000378:metabolism
chemical_list: D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; D018076:DNA, Complementary; D010940:Plant Proteins; D000644:Quaternary Ammonium Compounds; D018749:RNA, Plant; D011994:Recombinant Proteins