Virus-Resistant Transgenic Horticultural Crops: Safety Issues and Lessons from Risk Assessment Studies - Transgenic Horticultural Crops: Challenges and Opportunities - page 275

the.parental.variety. 100 . A. general.trend. of. decreasing. antinutrient. levels. was.noted.
during.ripening.in.transgenic.and.control.fruits..Similar.nonsigniicant.variations.in.
selected.horticultural.traits.(water,.lipid,.nitrogen,.protein,.reducing.sugar,.vitamin.A.
(and.its.precursor),.vitamin.C).were.obtained.with.transgenic.papaya.expressing.the.
replicase.gene.of.a.PRSV.isolate.from.the.People's.Republic.of.China. 67,101
Recently,. Powell. et. al. 102 . evaluated. the. safety. of. transgenic. papaya. in. a. sub-
chronic.feeding.study..A.diet.formulated.with.10%.transgenic.papaya,.the.equivalent.
of.twice.the.average.daily.human.consumption.of.fresh.papayas.based.on.food.con-
sumption.data.from.the.Caribbean.and.Latin.America, 103,104 .was.administered.to.rats.
for.90.consecutive.days..For.comparison,.reference.non-transgenic.papaya.'Sunrise.
solo',.from.which.the.transgenic.papaya.was.derived,.and.a.control.laboratory.rodent.
diet. formulation. were. also. evaluated.. Markers. of. general. health,. including. body.
weight,. food. intake,. and. activities. of. plasma,. liver,. and. kidney. function. enzymes.
(acid.and.alkaline.phosphatases.and.alanine.and.aspartate.transaminases).were.com-
parable.for.the.test,.reference,.and.control.groups..No.signiicant.effects.were.observed.
in.organ.weights.or.histopathology. 102 .Changes.in.the.liver.and.kidney,.the.sites.of.
biotransformation.and.detoxiication,.and.of.excretion.of.metabolic.waste.products,.
respectively,.were.not.observed. 102 .Overall,.the.plasma.cholesterol.levels,.which.are.
markers. of. cardiovascular. risk,. were. similar. to. the. control. as. were. triglycerides,.
which.are.biomarkers.for.hepatotoxicity..Although.not.statistically.relevant,.varia-
tions.in.the.values.of.the.parameters.monitored.with.the.control,.reference,.and.test.
groups.were.observed. 102 .Based.on.literature.ranges,.the.variations.were.attributed.to.
natural.biological.luctuations.and.were.not.regarded.as.relecting.a.toxicologically.
meaningful.effect.
In.addition.to.looking.at.the.effect.of.transgenes.on.papaya.fruit,.other.researchers.
have.focused.on.the.effects.of.transgenic.papaya.on.nontarget.organisms.including.
soil.microbial.organisms..Hsieh.and.Pan, 105 .looking.at.populations.of.fungi,.bacteria,.
and.actinomycetes.present.in.the.soil.from.ield.plantings.of.both.transgenic.and.non-
transgenic.ields,.found.highly.similar.(>80%).populations.in.both.soil.environments.
(transgenic.vs..non-transgenic).as.well.as.in.upper.and.lower.soils.within.the.environ-
ments..These.authors.concluded.that.the.planting.of.transgenic.papaya's.effect.on.the.
soil.microorganisms.is.limited. 105 .Minor.effects.on.nontargets.have.been.observed, 106 .
but. these. effects. are. varied. and.not. consistent. across. all. virus-resistant.transgenic.
crops.. Another. study,. also. examining.the. effects. of.transgenic.papaya. on. the. soil,.
relied.upon.polymerase.chain.reaction.to.determine.the.persistence.and.availability.
of. transgenic. genes. that. may. be. released. by. transgenic. papaya. during. growth. 107 .
Though. transgenic. DNA. was. detected. at. low. levels,. no. gene. transfer. events. from.
soil.DNA.extracts.to. Acinetobacter .(a.bacterium.well.known.for.its.ability.to.uptake.
foreign.DNA).were.observed. 107
t omato and S weet p epper r eSIStant to c ucumber m osAic V irus
Background
With.regard.to.transgenic.tomato.and.sweet.pepper.engineered.for.CMV.resistance,.
the. body. of. publications. is. much. smaller. than. for. the. aforementioned. transgenic.
crops.. Transgenic. tomato.and.sweet. pepper. containing. the.coat.protein. gene.from.