Virus-Resistant Transgenic Horticultural Crops: Safety Issues and Lessons from Risk Assessment Studies - Transgenic Horticultural Crops: Challenges and Opportunities - page 276

a.local.isolate.of.CMV.were.released.in.the.People's.Republic.of.China. 108 .CMV.is.
a.cucumovirus.that.is.transmitted.in.a.nonpersistent.manner.by.several.aphid.spe-
cies. 109 .It.has.the.widest.host.range.of.any.known.plant.virus.with.1300.species.in.
more. than. 500. genera. of. over. 100. families.. Control. of. CMV. can. be. achieved. by.
planting.resistant.crops.but.resistance.in.many.crops.species.is.often.not.available.to.
a.broad.range.of.CMV.strains. 109
Risk Studies
A. study. on. gene. low. was. performed. with. transgenic. sweet. pepper. and. tomato.
by. Ming. et. al. 110 . Seeds. and. pollen. of. many. different. plants. at. varying. distances.
from.ields.of.transgenic.plants.were.examined.to.determine.whether.gene.low.had.
occurred.. Selection. of. seedlings. on. antibiotic-containing. medium. and. polymerase.
chain.reaction.were.used.to.monitor.transgene.movement,.but.transfer.of.transgenes.
was.not.detected. 110
For. assurance. of. food. safety,. transgenic. sweet. peppers. and. tomatoes. express-
ing.the.coat.protein.gene.of.CMV.were.evaluated.in.animal.feeding.studies. 108 .The.
animals.received.about.12,600.and.7100.times.the.average.daily.human.consump-
tion.of.sweet.peppers.and.tomatoes,.respectively..Comparable.performance.of.rats.
fed.transgenic.and.non-transgenic.diets.was.demonstrated. 108 .Signiicant.differences.
were.not.reported.in.mean.weekly.body.weights,.body.weight.gains,.or.food.con-
sumption. of. rats. fed. transgenic. or. non-transgenic. sweet. pepper. and. tomato. diets..
Similarly,. signiicant. differences. were. not. observed. with. the. hematological. and.
blood. biochemical. parameters. monitored. (including. cholesterol. and. triglyceride),.
although.luctuations.in.the.values.were.observed. 108 .In.another.study,.Cai.et.al. 111 .
conducted.30-day.acute.toxicity.(LD 50 ).experiments.with.male.and.female.rats.and.
mice. using. gavage. administration. of. a. series. of. doses. ranging. from. 1. to. 10.g/kg.
body.weight.of.dry.pepper.fruit.containing.the.coat.protein.gene.of.TMV.and.CMV..
Abnormalities.in.body.weights,.organ.weights,.histopathology,.and.hematology.were.
not.observed. 111
EXAMINATION OF RISKS ASSOCIATED WITH TRANSGENIC PLUM
WHICH IS UNDER CONSIDERATION FOR DEREGULATION
b ackGround
Though. not. yet. commercially. available,. the. transgenic. plum. cultivar. 'Honey.
sweet'.(aka.C5).resistant.to. Plum pox virus .(PPV).has.been.deregulated.by.the.U.S..
Department.of.Agriculture's.Animal.and.Plant.Health.Inspection.Service.(USDA-
APHIS).and.registered.by.the.Environmental.Protection.Agency.(EPA).in.the.United.
States.and.is.being.widely.tested.in.Europe.under.varying.growing.conditions..PPV.
is.a.potyvirus.that.is.considered.the.most.important.pathogen.in. Prunus .by.the.U.S..
and.E.C..agencies. 112 .Conventional.breeding.has.not.been.able.to.produce.any.trees.
of.commercially.acceptable.varieties.with.high.resistance.to.PPV..Therefore,.control.
of.PPV.has.relied.on.prevention.via.certiied.planting.material,.quarantine.measures,.
and.eradication. 112 .PPV.is.spread.by.multiple.aphid.species,.but.control.of.the.vector.
is.not.feasible.for.both.eficacy.and.environmental.impact.reasons. 113