Transgenic Vegetables - Transgenic Horticultural Crops: Challenges and Opportunities - page 48

crops. that. include. canola,. corn,. potato,. and. soybean.. Transgenic. squash. and. zuc-
chini. with. virus. resistance.followed. tomato. as. the. next. vegetable. crop. in. the. U.S..
market.. This. chapter. has. summarized. many.other.potentially.beneicial.traits. that.
have. been. engineered. into. vegetable. crop. species.. Some. of. these. traits. can. be. of.
direct.beneit.to.the.grower,.e.g.,.insect.or.herbicide.resistance,.while.others.would.have.
beneits. to. the. consumer,. e.g.,. enhanced. vitamins,. lavor,.and. quality.. While. there.
appears.to.be.continuing.interest.in.the.applications.of.biotechnology.to.vegetable.
crop.species,.several.requirements.still.must.be.met.to.ensure.success.in.transforma-
tion..A.well.deined.and.reproducible.tissue-culture.system.is.needed,.together.with.
an.eficient.transformation.method.as.well.as.an.appropriate.selection.system.to.dis-
tinguish.transformed.cells.from.non-transformed.cells..While.an.increasing.number.
of. vegetable. crop. species. are. becoming. amenable. to. transformation. technologies,.
there.are.still.some.limitations..It.appears.that.only.a.few.techniques.are.available.
to.introduce.foreign.genes.into.vegetable.crop.species,.with.the.most.popular.being.
Agrobacterium -mediated. transformation.. Optimization. of. gene. transfer. methods,.
transformation.eficiencies,.and.tissue-culture.procedures.still.remain.a.challenge.for.
some.vegetable.species..The.most.amenable.species.appear.to.be.tomato.and.carrot.
There.are.also.other.issues.that.need.to.be.addressed.before.widespread.utility.of.
transgenic.vegetable.crop.species.occurs..The.traits.engineered.into.the.respective.
crops. need. to. be. evaluated. under. replicated. ield. conditions. over. several. years. to.
ensure.the.introduced.genes.confer.the.desired.phenotype..Furthermore,.the.horti-
cultural.attributes.in.the.transgenic.lines.should.be.similar.to.those.in.the.existing.
non-transgenic. cultivar.. These. lines. should. demonstrate. a. clear. advantage. (to. the.
grower,.the.consumer).compared.to.that.currently.existing.in.the.crop.species.germ-
plasm.. While. these. criteria. have. been. met. with. the. currently. approved. transgenic.
corn,.canola,.soybean,.and.potato.cultivars,.they.still.require.additional.effort.for.the.
transgenic.lines.of.vegetable.crops.under.study.
Consumer. acceptance. of. vegetable. crops. that. contain. transgenes. will. require.
that.the.same.stringent.criteria.used.to.evaluate.other.transgenic.food.plants.be.met..
Perhaps. more. so. than. transgenic. ield. crops,. transgenic. vegetable. crops. that. are.
consumed.fresh.may.face.additional.consumer.concerns.that.will.require.that.evi-
dence. of. their. beneits. be. made. clear.. In. the. case. of. vitamin-enhanced. tomatoes.
or. high-antioxidant. carrots,. these. could. provide. a. strong. example. of. the. potential.
beneits.of.the.transgenic.produce..The.other.issues.regarding.use.of.marker.genes,.
spread.of.the.transgenes.through.pollen,.potential.for.resistance.selection.in.the.case.
of.insect.or.fungal.pests,.and.allergenicity.of.the.introduced.protein.are.all.similar.to.
those.required.for.other.transgenic.crops.and.need.to.be.satisied.

REFERENCES
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1.. Punja,.Z..K..and.Feeney,.M.,.Progress.in.vegetable.crop.transformation.and.future.pros-
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Haworth.Press,.New.York,.2004,.Chap..12.

. 2.. Mahanil,.S..et.al.,.Overexpression.of.tomato.polyphenol.oxidase.increases.resistance.to.

common.cutworm,. Plant Sci .,.174,.456,.2008.

. 3.. Lawrence,. S..D.. and.Novak,.N.. G.,.Expression.of.poplar. chitinase. in. tomato. leads.to.

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