Agriculture Reference
In-Depth Information
Host plant genome
Non-transgenic plant
Transformation using
trait genes and a
gene deletor cassette
Integration of gene
deletor system and
trait genes into host
plant genome
Host plant
genome
Host plant
genome
Transgenic plant hosting trait
gene and a gene deletor system
Organ-specic or
conditionally inducible
expression of FLP
All transgenes including
the gene deletor system
are deleted from pollen
and seed if FLP is
expressed in pollen and
seed specically
All transgenes including
the gene deletor system
are deleted from the
entire plant if FLP is
conditionally expressed
in all cells
loxP - FRT
loxP - FRT
Deletion of all transgenes
in cells where FLP is
expressed
Excised transgenes
destroyed in the cell
Host plant genome
with transgenes deleted
in FLP expressed cells
Pollen and seed
reverted back to
non-transgenic
Entire plant
reverted back to
non-transgenic
FIGURE 14.1 (See color insert.) .Schematic.illustration.of.the.principle.of.the.gene.deletor.
technology..On.the.left,.an.application.of.the.gene.deletor.technology.to.generate.non-transgenic.
pollen,.seed,.or.plant.from.a.transgenic.plant.is.illustrated..The.schematics.presented.on.the.
right.show.an.FLP-mediated.transgene.deletion. at.the.DNA. level..Any.transgenes,. such.as.
trait.genes,.selection.marker.gene,.and. FLP .or. Cre .recombinase.gene.that.have.been.inserted.
into.the.two.loxP-FRT.sites.(86.bp.in.length),.will.be.deleted.from.any.cell,.in.which.the.FLP.
recombinase.is.expressed..When.a.pollen-.and.seed-speciic.gene.promoter.is.used.to.control.
recombinase.expression,.all.functional.transgenes.are.deleted.from.these.speciic.organs..If.a.
conditionally.inducible.gene.promoter,.such.as.chemically.or.high-temperature.inducible,.is.
used.to.control.recombinase.expression,.the.system.will.delete.all.transgenes.throughout.the.
plant.upon.induction..(Modiied.from.Luo,.K..et.al.,. Plant Biotechnol. J .,.5,.263,.2007;.Moon,.
H.S..et.al.,. Trends Biotechnol .,.28,.3,.2010.)
recognition. site. intact; 116-120 . FLP/FRT . and. Cre/loxP . function. through. interactions.
of.a.recombinase.with.its.speciic.recognition.sites. 116-120 .Traditionally,.site-speciic.
DNA.recombination.systems,.such.as.bacterial.phage. Cre/loxP .and. Saccharomyces
cerevisiae FLP/FRT . systems,. have. been. used. to. excise. marker. genes. or. short.
spacer.sequences.in.higher.plants. 114,121 .Recombinase.recognizes.these.lanking.rec-
ognition.sites.and.excises.any.intervening.DNA..Further,.in.addition.to.DNA.recom-
bination.systems,.other.site-speciic.DNA.excision.systems.can.also.be.used.in.the.
gene.deletor.technology.
With.a.combined.use.of.loxP.and.FRT.sequences.as.the.lanking.sites.for. FLP .
or. Cre . recombinase,. we. have. observed. high. eficiency. for. deleting. all. functional.
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