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December 21, 2007
Source:
CropBiotech Update
Over the past few years, consumer
and environmental groups have expressed concern about the use of
markers in genetic improvement of crops. Marker genes are used
in plant transformation systems to select transgenic events.
However, they are no longer needed after the transgenic plants
are regenerated. Until recently, scientists have devised several
ways to produce marker-free transgenic crops. One such strategy
is the use of jumping genes. Jumping genes or transposons are so
called because they have the ability to move around to different
positions within the genome in a cell.
Using the maize transposon Ac system, scientists from the
National Taiwan University have developed a strategy for
efficiently removing the marker genes from transgenic plants.
The scientists modified the selectable marker esps gene (for
glyphosate tolerance) for expression in rice by introducing it
to a gene carrier with the salicylic acid inducible jumping
genes attached to it. After rice transformation,
glyphosate-tolerant rice lines were selected and exposed to
salicylic acid. Since the marker gene is attached to the
transposon, the activation of the jumping gene resulted to the
truncation of the selectable marker gene.
An inducible transposon system
to terminate the function of a selectable marker in transgenic
plants
Journal Molecular Breeding
Publisher Springer Netherlands
ISSN 1380-3743 (Print) 1572-9788 (Online)
The abstract of the paper
published by Molecular Breeding is available at
http://www.springerlink.com/content/6720mj4607787451/?p=3c79ad37742f4e4fa77130f361884de7&pi=4
Subscribers can read the full text at
http://www.springerlink.com/content/6720mj4607787451/fulltext.pdf
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