Background: Currently, the technology called Clearfield\uae is used
in the development of crops resistant to herbicides that inhibit the
enzyme acetohydroxy acid synthase (AHAS, EC 2.2.1.6). AHAS is the first
enzyme of the biosynthetic pathway that produces the branched-chain of
the essential amino acids valine, leucine, and isoleucine. Therefore,
multiple copies of the AHAS gene might be of interest for breeding
programs targeting herbicide resistance. In this work, the
characterization of the AHAS gene was accomplished for the Chenopodium
quinoa Regalona-Baer cultivar. Cloning, sequencing, and Southern
blotting were conducted to determine the number of gene copies.
Results: The presence of multiple copies of the AHAS gene as has been
shownpreviously in several other species is described. Six copies of
the AHAS gene were confirmed with Southern blot analyses. CqHAS1 and
CqAHAS2 variants showed the highest homology with AHAS mRNA sequences
found in the NR Database. A third copy, CqAHAS3, shared similar
fragments with both CqAHAS1 and CqAHAS2, suggesting duplication through
homeologous chromosomes pairing. Conclusions: The presence of
multiple copies of the gene AHAS shows that gene duplication is a
common feature in polyploid species during evolution. In addition, to
our knowledge, this is the first report of the interaction of
sub-genomes in quinoa