title: Genes encoding 4-Cys antimicrobial peptides in wheat Triticum kiharae Dorof. et Migush.: multimodular structural organization, instraspecific variability, distribution and role in defence.
abstract: A novel family of antifungal peptides was discovered in the wheat Triticum kiharae Dorof. et Migusch. Two members of the family, designated Tk-AMP-X1 and Tk-AMP-X2, were completely sequenced and shown to belong to the α-hairpinin structural family of plant peptides with a characteristic C1XXXC2-X(n)-C3XXXC4 motif. The peptides inhibit the spore germination of several fungal pathogens in vitro. cDNA and gene cloning disclosed unique structure of genes encoding Tk-AMP-X peptides. They code for precursor proteins of unusual multimodular structure, consisting of a signal peptide, several α-hairpinin (4-Cys) peptide domains with a characteristic cysteine pattern separated by linkers and a C-terminal prodomain. Three types of precursor proteins, with five, six or seven 4-Cys peptide modules, were found in wheat. Among the predicted family members, several peptides previously isolated from T. kiharae seeds were identified. Genes encoding Tk-AMP-X precursors have no introns in the protein-coding regions and are upregulated by fungal pathogens and abiotic stress, providing conclusive evidence for their role in stress response. A combined PCR-based and bioinformatics approach was used to search for related genes in the plant kingdom. Homologous genes differing in the number of peptide modules were discovered in phylogenetically-related Triticum and Aegilops species, including polyploid wheat genome donors. Association of the Tk-AMP-X genes with A, B/G or D genomes of hexaploid wheat was demonstrated. Furthermore, Tk-AMP-X-related sequences were shown to be widespread in the Poaceae family among economically important crops, such as barley, rice and maize.
authors.affiliation: Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia. lyuba_utk@mail.ru
authors.forename: Lyubov L
authors.initials: LL
authors.lastname: Utkina
authors.forename: Yaroslav A
authors.initials: YA
authors.lastname: Andreev
authors.forename: Eugene A
authors.initials: EA
authors.lastname: Rogozhin
authors.forename: Tatyana V
authors.initials: TV
authors.lastname: Korostyleva
authors.forename: Anna A
authors.initials: AA
authors.lastname: Slavokhotova
authors.forename: Peter B
authors.initials: PB
authors.lastname: Oparin
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Vassilevski
authors.forename: Eugene V
authors.initials: EV
authors.lastname: Grishin
authors.forename: Tsezi A
authors.initials: TA
authors.lastname: Egorov
authors.forename: Tatyana I
authors.initials: TI
authors.lastname: Odintsova
mesh_terms: D000595:Amino Acid Sequence; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000235:genetics*; D017124:Conserved Sequence; D060467:Disease Resistance / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics*; D011499:Protein Processing, Post-Translational; D017433:Protein Structure, Secondary; D059748:Proteolysis; D036226:Seedlings / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D013312:Stress, Physiological; D014908:Triticum / Q000235:genetics*
chemical_list: D023181:Antimicrobial Cationic Peptides; D010940:Plant Proteins
keywords: cDNA and genomic DNA cloning; plant antimicrobial peptides; stress response; wheat evolution; α-hairpinin family