Transgenic Ornamental Crops - Transgenic Horticultural Crops: Challenges and Opportunities - page 74

that. elicit. plant. defense. responses. and. are. often. induced. in. response. to. pathogen.
attack.(reviewed.by.Stintzi.et.al. 140 )..Blackspot.is.a.common,.problematic.disease.in.
Rosa hybrida . and. is. caused. by. the. fungus. Diplocarpon rosae .. Transformation. of.
rose. via. particle. bombardment. with. a. rice. basic. chitinase. gene. reduced. blackspot.
severity. by. 13%-43%. with. lesion. size. reduced. by. up. to. half. of. those. of. control.
blackspot. lesions. 141 . A. PR. gene. encoding. for. a. cysteine-rich. antimicrobial. protein.
(AMP).confers.disease.resistance.in.plants..Enhanced.tolerance.to.powdery.mildew.
was.observed.in.transgenic.rose.plants.constitutively.expressing.an.AMP.gene.from.
onion. 142 .The.onion.AMP.was.also.introduced.into. Pelargonium .for.enhanced.resis-
tance.to. Botrytis . 143 .In.leaf.disc.assays,. Botrytis .sporulation.was.slightly.reduced.in.
transgenic.lines..Greater.disease.protection.is.observed.in.transgenic.plants.expressing.
more.than.one.PR.gene.and.this.should.be.considered.in.development.of.transgenic.
plants.with.enhanced.disease.resistance. 144
CURRENT AND FUTURE ISSUES IN ORNAMENTAL
BIOTECHNOLOGY
Despite. the. documented. technical. successes,. utility,. and. the. enormous. beneits.
genetic. engineering. rewards,. there. are. only. a. limited. number. of. commercialized.
transgenic. ornamental. plants. on. the. market.. Presently,. the. only. commercialized.
ornamental. plants. on. the. market. are. carnations. engineered. for. blue-violet. color. 145 .
This.is.in.stark.contrast.to.the.rapid.adoption.of.genetically.engineered.agronomic.
crops.since.their.introduction.in.1996.with.transgenic.plants.accounting.for.well.over.
50%-90%.of.planted.acreage.of.corn,.soybean,.and.cotton.in.2008.(http://www.ers.
usda.gov/Data/BiotechCrops/)..The.lack.of.commercialized.transgenic.ornamentals.
is.not.due.to.lack.of.potential.products,.but.is.impeded.by.regulatory.issues.concern-
ing.safety,.consumer.acceptance,.intellectual.property,.postcommercialization.moni-
toring.of.transgenic.crops,.and.the.diversity.of.germplasm.requiring.development.of.
a.biotech.trait. 2 .While.ornamental.crops.are.grown.for.aesthetic.purposes.and.do.not.
require.human.health.safety.testing,.they.are.subject.to.strict.handling.procedures,.
ield-testing,.tracking,.and.postcommercialization.stewardship..All.of.these.increase.
the.costs.of.developing.a.biotech.crop.to.at.least.$1.million.for.one.transgenic.event.
per.country, 132 .making.it.dificult.to.justify.use.of.biotechnology.in.the.ornamental.
market.where.crop.values.are.signiicantly.lower.than.agronomic.crops..With.turn-
over. of. new.varieties.in. ornamental. crops,. sales.are.not.high.enough.to.generate.a.
proit.that.would.offset.the.costs.to.bring.a.transgenic.plant.to.market.
Regulatory.issues.pose.a.signiicant.obstacle.to.the.development.and.commercial-
ization.of.genetically.engineered.crops..Any.organism.that.has.been.modiied.through.
genetic.manipulation.technology.is.subject.to.regulation.by.overseeing.agencies,.such.
as.the.United.States. Department. of.Agriculture.(USDA),.Animal.and.Plant.Health.
Inspection.Service.(APHIS),.Environmental.Protection.Agency.(EPA),.and.Food.and.
Drug.Administration.(FDA).in.the.United.States,.which.oversees.introduction,.trans-
port,.risks.to.human.health,.and.environmental.risk.assessment.of.the.genetically.or.
living.modiied.organism.(GMO.or.LMO,.respectively)..The.regulations.and.proce-
dures.vary.by.country,.creating.additional.complications.in.releasing.a.GMO.interna-
tionally.(reviewed.by.Chandler.and.Tanaka 16 ),.but.the.goals.of.regulating.GMOs.are.