title: Expansion of the phosphatidylethanolamine binding protein family in legumes: a case study of Lupinus angustifolius L. FLOWERING LOCUS T homologs, LanFTc1 and LanFTc2.
abstract: The Arabidopsis FLOWERING LOCUS T (FT) gene, a member of the phosphatidylethanolamine binding protein (PEBP) family, is a major controller of flowering in response to photoperiod, vernalization and light quality. In legumes, FT evolved into three, functionally diversified clades, FTa, FTb and FTc. A milestone achievement in narrow-leafed lupin (Lupinus angustifolius L.) domestication was the loss of vernalization responsiveness at the Ku locus. Recently, one of two existing L. angustifolius homologs of FTc, LanFTc1, was revealed to be the gene underlying Ku. It is the first recorded involvement of an FTc homologue in vernalization. The evolutionary basis of this phenomenon in lupin has not yet been deciphered.
  
  
  
  Bacterial artificial chromosome (BAC) clones carrying LanFTc1 and LanFTc2 genes were localized in different mitotic chromosomes and constituted sequence-specific landmarks for linkage groups NLL-10 and NLL-17. BAC-derived superscaffolds containing LanFTc genes revealed clear microsyntenic patterns to genome sequences of nine legume species. Superscaffold-1 carrying LanFTc1 aligned to regions encoding one or more FT-like genes whereas superscaffold-2 mapped to a region lacking such a homolog. Comparative mapping of the L. angustifolius genome assembly anchored to linkage map localized superscaffold-1 in the middle of a 15 cM conserved, collinear region. In contrast, superscaffold-2 was found at the edge of a 20 cM syntenic block containing highly disrupted collinearity at the LanFTc2 locus. 118 PEBP-family full-length homologs were identified in 10 legume genomes. Bayesian phylogenetic inference provided novel evidence supporting the hypothesis that whole-genome and tandem duplications contributed to expansion of PEBP-family genes in legumes. Duplicated genes were subjected to strong purifying selection. Promoter analysis of FT genes revealed no statistically significant sequence similarity between duplicated copies; only RE-alpha and CCAAT-box motifs were found at conserved positions and orientations.
  
  
  
  Numerous lineage-specific duplications occurred during the evolution of legume PEBP-family genes. Whole-genome duplications resulted in the origin of subclades FTa, FTb and FTc and in the multiplication of FTa and FTb copy number. LanFTc1 is located in the region conserved among all main lineages of Papilionoideae. LanFTc1 is a direct descendant of ancestral FTc, whereas LanFTc2 appeared by subsequent duplication.
authors: Institute of Plant Genetics of the Polish Academy of Sciences, Strzeszyńska 34, 60-479, Poznań, Poland. mksi@igr.poznan.pl.
authors: Michał
authors: 0000-0002-3382-8504
authors: M
authors: Książkiewicz
authors: Institute of Plant Genetics of the Polish Academy of Sciences, Strzeszyńska 34, 60-479, Poznań, Poland.
authors: Sandra
authors: S
authors: Rychel
authors: Natural Capital and Plant Health, Royal Botanic Gardens Kew, Wakehurst Place, Ardingly, West Sussex, RH17 6TN, UK.|School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia.|The UWA Institute of Agriculture, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia.
authors: Matthew N
authors: MN
authors: Nelson
authors: Institute of Plant Genetics of the Polish Academy of Sciences, Strzeszyńska 34, 60-479, Poznań, Poland.
authors: Katarzyna
authors: K
authors: Wyrwa
authors: Institute of Plant Genetics of the Polish Academy of Sciences, Strzeszyńska 34, 60-479, Poznań, Poland.
authors: Barbara
authors: B
authors: Naganowska
authors: Institute of Plant Genetics of the Polish Academy of Sciences, Strzeszyńska 34, 60-479, Poznań, Poland.
authors: Bogdan
authors: B
authors: Wolko
mesh_terms: D002874:Chromosome Mapping; D019143:Evolution, Molecular; D020869:Gene Expression Profiling; D008040:Genetic Linkage; D018745:Genome, Plant; D023281:Genomics; D031297:Lupinus / Q000145:classification / Q000235:genetics*; D005810:Multigene Family; D049488:Phosphatidylethanolamine Binding Protein / Q000235:genetics*; D010802:Phylogeny; D011401:Promoter Regions, Genetic; D026801:Synteny
chemical_list: D049488:Phosphatidylethanolamine Binding Protein
keywords: BAC-FISH; DNA sequencing; Duplication; Flowering locus T; Genomics; Lupinus angustifolius; Phosphatidylethanolamine binding protein; Synteny