The wheat D-genome HMW-glutenin locus: BAC sequencing, gene distribution, and retrotransposon clusters

Funct Integr Genomics. 2003 Mar;3(1-2):56-68. doi: 10.1007/s10142-002-0069-z. Epub 2002 Aug 14.

Abstract

A bacterial-artificial-chromosome (BAC) clone from the genome of Triticum tauschii, the D-genome ancestor of hexaploid bread wheat, was sequenced and the presence of the two paralogous x- and y-type high-molecular-weight (HMW) glutenin genes of the Glu-D1 locus was confirmed. These two genes occur in the same orientation, are 51,893 bp apart, and the separating DNA includes a 31,000-bp cluster of retrotransposons. A second retrotransposon cluster of 32,000 bp follows the x-type HMW-glutenin gene region. Each HMW-glutenin gene is found within a region of mainly unique DNA sequence which includes multiple additional genes including an active endosperm globulin gene not previously reported in the Triticeae family, a leucine-rich-repeat (LRR) type gene truncated at the 5' end of the BAC, a kinase gene of unknown activity, remnants of a paralogous second globulin gene, and genes similar to two hypothetical rice genes. The newly identified globulin genes are assigned to a locus designated Glo-2. Comparison to available orthologous regions of the wheat A and B genomes show rapid sequence divergences flanking the HMW-glutenin genes, and the absence of two hypothetical and unknown genes found 5' to the B-genome x-type ortholog. The region surrounding the Glu-D1 locus is similar to other reported Triticeae BAC sequences; i.e. small gene islands separated by retrotransposon clusters.

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Chromosomes, Artificial, Bacterial
  • Cloning, Molecular
  • DNA / ultrastructure
  • DNA Transposable Elements*
  • Gene Library
  • Genome, Plant*
  • Glutens / analogs & derivatives*
  • Glutens / genetics*
  • Leucine / chemistry
  • Models, Genetic
  • Molecular Sequence Data
  • Protein Kinases / genetics
  • Protein Structure, Tertiary
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid
  • Triticum / genetics*

Substances

  • DNA Transposable Elements
  • Glutens
  • DNA
  • Protein Kinases
  • glutenin
  • Leucine