title: Molecular characterization and genomic mapping of the pathogenesis-related protein 1 (PR-1) gene family in hexaploid wheat (Triticum aestivum L.).
abstract: The group 1 pathogenesis-related (PR-1) proteins, known as hallmarks of defense pathways, are encoded by multigene families in plants as evidenced by the presence of 22 and 32 PR-1 genes in the finished Arabidopsis and rice genomes, respectively. Here, we report the initial characterization and mapping of 23 PR-1-like (TaPr-1) genes in hexaploid wheat (Triticum aestivum L.), which possesses one of the largest (>16,000 megabases) genomes among monocot crop plants. Sequence analysis revealed that the 23 TaPr-1 genes all contain intron-free open reading frames that encode a signal peptide at the N-terminus and a conserved PR-1-like domain. Phylogenetic analysis indicated that TaPr-1 genes form three major monophyletic groups along with their counterparts in other monocots; each group consists of genes encoding basic, basic with a C-terminal extension, and acidic PR-1 proteins, respectively, suggesting diversity and conservation of PR-1 gene functions in monocot plants. Mapping analysis assisted by untranslated region-specified discrimination (USD) markers and various cytogenetic stocks located the 23 TaPr-1 genes to seven different chromosomes, with the majority mapping to chromosomes of homoeologous groups 5 and 7. Reverse transcriptase (RT)-PCR analysis revealed that 12 TaPr-1 genes were induced or up-regulated upon pathogen challenge. Together, this study provides insights to the origin, evolution, homoeologous relationships, and expression patterns of the TaPr-1 genes. The data presented provide critical information for further genome-wide characterization of the wheat PR-1 gene family and the USD markers developed will facilitate genetic and functional analysis of PR-1 genes associated with plant defense and/or other important traits.
authors.affiliation: USDA-ARS, Cereal Crops Research Unit, Northern Crop Science Laboratory, Fargo, ND 58102-2765, USA. Shunwen.Lu@ars.usda.gov
authors.forename: Shunwen
authors.initials: S
authors.lastname: Lu
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Friesen
authors.forename: Justin D
authors.initials: JD
authors.lastname: Faris
mesh_terms: D000890:Anti-Infective Agents; D002874:Chromosome Mapping; D017343:Genes, Plant / Q000235:genetics* / Q000276:immunology; D018745:Genome, Plant; D010940:Plant Proteins / Q000235:genetics* / Q000276:immunology; D014908:Triticum / Q000235:genetics*
chemical_list: D000890:Anti-Infective Agents; D010940:Plant Proteins; C053376:pathogenesis-related proteins, plant