The phosphatidylethanolamine binding protein (PEBP) family comprises ancient proteins found throughout the biosphere that play an important role in plant growth and development, flowering, seed development and dormancy. However, not all PEBP genes have been identified or analyzed in common wheat (Triticum aestivum L.) and its progenitors. In this study, we identified the PEBP genes in common wheat, Triticum dicoccoides, Triticum urartu and Aegilops tauschii by searching whole genome sequences, and characterized these genes by phylogenetic and transcriptome analyses. A total of 76, 38, 16 and 22 PEBP genes were identified in common wheat, T. dicoccoides, T. urartu and Ae. tauschii, respectively. Phylogenetic analysis classified the PEBP genes into four subfamilies (PEBP-like, MFT-like, TFL-like and FT-like); the PEBP-like subfamily was identified as a new subfamily with genes in this subfamily were conserved in plants. Group 2, 3 and 5 chromosomes of common wheat and its progenitors contained more PEBP genes than other chromosomes. The PEBP genes were conserved in wheat during evolution, and tandem duplication played a more important role in the amplification of PEBP genes than segmental duplication. Furthermore, transcriptome analysis revealed that PEBP genes showed tissue/organ-specific expression profiles and some PEBP genes were induced to express by biotic stresses. Quantitative real-time PCR (qRT-PCR) analysis revealed that seven randomly selected PEBP genes expressed differently during seed germination under cold, drought, flood, heat and salt stress treatments, and five of these genes (TaPEBP1, TaPEBP5, TaPEBP9, TaPEBP66 and TaPEBP69) showed significantly higher expression under different stress treatments, indicating that these genes play important roles during seed germination under stress conditions.

Soil-borne wheat mosaic virus (SBWMV) causes a serious viral disease that can significantly reduce grain yield in winter wheat worldwide. Using resistant cultivars is the only feasible strategy to reduce the losses caused by SBWMV. To fine map the resistance gene Sbwm1, 205 wheat accessions was genotyped using wheat Infinium iSelect Beadchips with 90 K SNPs. Association analysis identified 35 SNPs in 12 wheat genes and one intergenic SNP in the Sbwm1 region that showed a significant association with SBWMV resistance. Those SNPs were converted into Kompetitive Allele-Specific Polymerase assays (KASP) and analyzed in two F₆-derived recombinant inbred line (RIL) populations derived from the crosses between two resistant cultivars ‘Wesley’ and ‘Deliver’ and a susceptible line ‘OK03825-5403-6’. Linkage analysis mapped this gene on chromosome 5D at intervals of 5.1 cM and 3.4 cM in the two populations, respectively. The two flanking markers in both populations delimited the gene to a 620 kb region where 19 genes were annotated. Comparative analysis identified a syntenic region of 660 kb in Ae. tauschii with 18 annotated genes and a syntenic region in chromosome 1 of B. distachyon. The candidate region includes several disease resistance related genes and we identified a PTI1-like tyrosine-protein kinase 1 gene as a putative candidate gene for Sbwm1. The two flanking SNPs for Sbwm1 can effectively separate the resistant and susceptible lines in a new diversity panel of 159 wheat germplasm. The results from this study lay a solid foundation for the cloning, functional characterization and marker-assisted selection of Sbwm1.