Genes encoding 4-Cys antimicrobial peptides in wheat Triticum kiharae Dorof. et Migush.: multimodular structural organization, instraspecific variability, distribution and role in defence

FEBS J. 2013 Aug;280(15):3594-608. doi: 10.1111/febs.12349. Epub 2013 Jun 18.

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.

Keywords: cDNA and genomic DNA cloning; plant antimicrobial peptides; stress response; wheat evolution; α-hairpinin family.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Antimicrobial Cationic Peptides / chemistry
  • Antimicrobial Cationic Peptides / genetics*
  • Conserved Sequence
  • Disease Resistance / genetics*
  • Molecular Sequence Data
  • Phylogeny
  • Plant Proteins / chemistry
  • Plant Proteins / genetics*
  • Protein Processing, Post-Translational
  • Protein Structure, Secondary
  • Proteolysis
  • Seedlings / genetics*
  • Sequence Homology, Amino Acid
  • Species Specificity
  • Stress, Physiological
  • Triticum / genetics*

Substances

  • Antimicrobial Cationic Peptides
  • Plant Proteins

Associated data

  • GENBANK/HF562347
  • GENBANK/HF562348
  • GENBANK/HF562349
  • GENBANK/HF562350
  • GENBANK/HF562351
  • GENBANK/HF562352
  • GENBANK/HF562353
  • GENBANK/HF562354
  • GENBANK/HF562355
  • GENBANK/HF562356
  • GENBANK/HF562357
  • GENBANK/HF562358
  • GENBANK/HF562359
  • GENBANK/HF562360
  • GENBANK/HF562361
  • GENBANK/HF562362
  • GENBANK/HF562363
  • GENBANK/HF562364