Novel LMW glutenin subunit genes from wild emmer wheat (Triticum turgidum ssp. dicoccoides) in relation to Glu-3 evolution

Dev Genes Evol. 2015 Jan;225(1):31-7. doi: 10.1007/s00427-014-0484-x. Epub 2014 Nov 25.

Abstract

Four low-molecular-weight-isoleucine (LMW-i)-type and one novel chimeric (between LMW-i and LMW-methionine (m) types) low-molecular-weight glutenin subunit (LMW-GS) genes were characterized from wild emmer wheat (Triticum dicoccoides), designated as emmer-1 to emmer-5. All five LMW-GS genes possessed the same primary structure shared by other published LMW-GSs. The three genes emmer-1, emmer-3, and emmer-5 are similar, with the exception that emmer-3 and emmer-5 lost a few repeat motifs compared to emmer-1. Gene duplication and insertions/deletions of repeat motifs mediated through unequal crossing over may be responsible for the generation of these three Glu-3 alleles. Although the first residue of mature peptide of emmer-4 is isoleucine, it is not typical LMW-i-type LMW-GS. Phylogenetic analysis indicated that emmer-4 is located in the LMW-m subgroup, suggesting a closer relationship with LMW-m-type gene Y14104 of T. durum. Sequence alignment indicated that the emmer-4 is likely a chimeric gene generated by illegitimate recombination between LMW-i and LMW-m type. Unequal crossing over and illegitimate recombination are effective mechanisms for enriching both copy numbers and variations of LMW-GSs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Evolution, Molecular
  • Genes, Plant
  • Glutens / chemistry
  • Glutens / genetics*
  • Molecular Sequence Data
  • Molecular Weight
  • Phylogeny
  • Prolamins / chemistry
  • Prolamins / genetics
  • Sequence Alignment
  • Triticum / genetics*

Substances

  • Prolamins
  • Glutens
  • glutenin