Background:
Currently, the technology called Clearfield® 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.
