title: Differential phylogenetic expansions in BAHD acyltransferases across five angiosperm taxa and evidence of divergent expression among Populus paralogues.
abstract: BACKGROUND
  BAHD acyltransferases are involved in the synthesis and elaboration of a wide variety of secondary metabolites. Previous research has shown that characterized proteins from this family fall broadly into five major clades and contain two conserved protein motifs. Here, we aimed to expand the understanding of BAHD acyltransferase diversity in plants through genome-wide analysis across five angiosperm taxa. We focus particularly on Populus, a woody perennial known to produce an abundance of secondary metabolites.
  
  
  RESULTS
  Phylogenetic analysis of putative BAHD acyltransferase sequences from Arabidopsis, Medicago, Oryza, Populus, and Vitis, along with previously characterized proteins, supported a refined grouping of eight major clades for this family. Taxon-specific clustering of many BAHD family members appears pervasive in angiosperms. We identified two new multi-clade motifs and numerous clade-specific motifs, several of which have been implicated in BAHD function by previous structural and mutagenesis research. Gene duplication and expression data for Populus-dominated subclades revealed that several paralogous BAHD members in this genus might have already undergone functional divergence.
  
  
  CONCLUSIONS
  Differential, taxon-specific BAHD family expansion via gene duplication could be an evolutionary process contributing to metabolic diversity across plant taxa. Gene expression divergence among some Populus paralogues highlights possible distinctions between their biochemical and physiological functions. The newly discovered motifs, especially the clade-specific motifs, should facilitate future functional study of substrate and donor specificity among BAHD enzymes.
authors.affiliation: Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602-2152, USA.
authors.forename: Lindsey K
authors.initials: LK
authors.lastname: Tuominen
authors.forename: Virgil E
authors.initials: VE
authors.lastname: Johnson
authors.forename: Chung-Jui
authors.initials: CJ
authors.lastname: Tsai
mesh_terms: D000217:Acyltransferases / Q000737:chemistry / Q000145:classification* / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D017124:Conserved Sequence; D019143:Evolution, Molecular; D020440:Gene Duplication; D018506:Gene Expression Regulation, Plant; D018745:Genome, Plant / Q000235:genetics; D023281:Genomics; D008969:Molecular Sequence Data; D010802:Phylogeny; D032107:Populus / Q000145:classification* / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
chemical_list: D000217:Acyltransferases