DISCUSSION Tomatoisoneoftheworld'sl

DISCUSSION Tomatoisoneoftheworld'slargestvegetablecrops

andknownasprotectivefoodbothbecauseofitsimportantnutritivevalueandalsobecauseofitswidespreadproduction.Theprincipallimitationtotomatoproductionisdamagecausedbyfungi,nematode,

bacteriaandvirus.TYLCVinfectionprovokesrigorousyieldlossesviaflowerdrop,reductionofleafletarea,yellowingofyoungleavesandimpedesfruitsetinthetomatocrop.Iftheinfectionoccursattheearly

stageofthegrowth,yieldlossrisesupto100%.

TheavailabilityofPCR­basedmarkersformany

resistancegenesallowstheMASforbegomovirusresistanceintomatotobesuccessfullyappliedwithouttheneedforhighlysophisticatedtechniques.Inaddition,therapiddevelopmentofnewmolecular

techniques,combinedwiththeincreasingknowledgeonstructureandfunctionofresistancegenes[23].Indeed,onceamarker

Inaddition,therapiddevelopmentofnewmoleculartechniques,combinedwiththeever­increasingknowledgeaboutthestructureandfunctionofresistancegenes[23],willhelptoidentifynewmolecular

markersforMAS.

TheRAPDmethod,whichwasappliedwithUBC264

andUCB697,wasusedtoscreenthetomatolinesforresistancetoTYLCV.Jietal.[21]reportedthatUBC697,whichiscloselylocatednearTy­1 gene,andUBC264markersshowedtightlinkagetotheTYLCV

resistantgenes.TheystatedRAPDmarkersUBC697andUBC264canbeusedinplantbreedingselectionforTYLCVandToMoVresistance.Inthisstudythe750bpfragment

(Figure1)wasobtainedin30outof131F3plantsderived

from11F2populationsusingUBC264marker.

AmplificationwithUBC697markerrevealed1165bp

fragmentfor120outofthe131plants.

TheCAPSmethod,appliedwithREX­1marker,

wasusedtodeterminegenotypicconstitutionofTy­1 gene

in131F3plantsoriginatedfrom11F2populations

(individualnumbersvariedfrom10to14foreach

population,atotalof131individuals).TheCAPSmethodcanberecommendedforfastandprecisedeterminationofresistanceorsusceptibilityoftomatoplantsagainsttheTYLCV.Thegoalofthemethodwas

thepossibilityofdetectionofgenotypicconstitutionofTy­1 genethatcansignificantlyspeeduptheprocessofcreationofnewresistantvarieties.FortheREX­1marker,threedifferentallelesappearedinS.

lycopersicum plantmaterial[24].TwoofthesealleleswerepreviouslydescribedbyWilliamsonetal.[22].Allele1consistedofabandof750bpandallele2oftwobandsofapproximately570and160bp.These

twoalleleswereco­dominant.Castroetal.[24]foundonemoreallele,allele3,whichpresentedthreebandsof350,220and160bp.Inthisstudy107plantswerefoundtobesusceptibleand15outof131were

heterozygousfortheresistancegene.Restoftheplantsdidnothaveprimerannealingsitesandnohomozygousresistantplantswerefound.Allele2,whichispresentinS. chilense LA1969,thesourceofthisgene,

isnotfrequentlyintrogressedalongwithTy­1.Therefore,REX­1markerandTy­1 arenottightlylinkedtoTYLCD.Inotherwords,markerREX­1isnotusefulinmarker­assistedselectionforTy­1 [24].

Furthermore,ithasbeenreportedthatbegomovirus­resistantlinesderivedfromS. habrochaites thataresusceptibletoM.incognitagivefalsepositiveresultsfortheREX­1marker[24].

ItshouldbenotedthatfailureoftheenzymeTaqI to

cleavetheampliconfromtheplantsderivedalleleofREX­1wouldresultinincorrectlyscoringahomozygousresistantplantassusceptible.

Kết quả (Việt) 1:

Thảo luận Tomatoisoneoftheworld'slargestvegetablecrops

andknownasprotectivefoodbothbecauseofitsimportantnutritivevalueandalsobecauseofitswidespreadproduction.Theprincipallimitationtotomatoproductionisdamagecausedbyfungi, giun,

bacteriaandvirus.TYLCVinfectionprovokesrigorousyieldlossesviaflowerdrop, reductionofleafletarea, yellowingofyoungleavesandimpedesfruitsetinthetomatocrop.Iftheinfectionoccursattheearly

stageofthegrowth,yieldlossrisesupto100%.

TheavailabilityofPCRbasedmarkersformany

resistancegenesallowstheMASforbegomovirusresistanceintomatotobesuccessfullyappliedwithouttheneedforhighlysophisticatedtechniques.Inaddition,therapiddevelopmentofnewmolecular

techniques,combinedwiththeincreasingknowledgeonstructureandfunctionofresistancegenes[23].Thật vậy, onceamarker

Inaddition, therapiddevelopmentofnewmoleculartechniques, combinedwiththeeverincreasingknowledgeaboutthestructureandfunctionofresistancegenes [23], willhelptoidentifynewmolecular

markersforMAS.

TheRAPDmethod, whichwasappliedwithUBC264

andUCB697, wasusedtoscreenthetomatolinesforresistancetoTYLCV.Jietal.[21] reportedthatUBC697, whichiscloselylocatednearTy1 gen,andUBC264markersshowedtightlinkagetotheTYLCV

resistantgenes.TheystatedRAPDmarkersUBC697andUBC264canbeusedinplantbreedingselectionforTYLCVandToMoVresistance.Inthisstudythe750bpfragment

(Figure1) wasobtainedin30outof131F3plantsderived

from11F2populationsusingUBC264marker.

AmplificationwithUBC697markerrevealed1165bp

fragmentfor120outofthe131plants.

TheCAPSmethod, appliedwithREX1marker,

wasusedtodeterminegenotypicconstitutionofTy1 gene

in131F3plantsoriginatedfrom11F2populations

(individualnumbersvariedfrom10to14foreach

population,atotalof131individuals).TheCAPSmethodcanberecommendedforfastandprecisedeterminationofresistanceorsusceptibilityoftomatoplantsagainsttheTYLCV.Thegoalofthemethodwas

thepossibilityofdetectionofgenotypicconstitutionofTy1 genethatcansignificantlyspeeduptheprocessofcreationofnewresistantvarieties.FortheREX1marker, threedifferentallelesappearedinS.

lycopersicum plantmaterial [24].TwoofthesealleleswerepreviouslydescribedbyWilliamsonetal.[22].Allele1consistedofabandof750bpandallele2oftwobandsofapproximately570and160bp.these

twoalleleswerecodominant.Castroetal.[24] foundonemoreallele, allele3, whichpresentedthreebandsof350, 220and160bp.Inthisstudy107plantswerefoundtobesusceptibleand15outof131were

heterozygousfortheresistancegene.Restoftheplantsdidnothaveprimerannealingsitesandnohomozygousresistantplantswerefound.Allele2,whichispresentinS. chilense LA1969,thesourceofthisgene,

isnotfrequentlyintrogressedalongwithTy1.Therefore,REX1markerandTy1 arenottightlylinkedtoTYLCD.Inotherwords,markerREX1isnotusefulinmarkerassistedselectionforTy1 [24].

Furthermore, ithasbeenreportedthatbegomovirusresistantlinesderivedfromS. habrochaites thataresusceptibletoM.incognitagivefalsepositiveresultsfortheREX1marker[24].

ItshouldbenotedthatfailureoftheenzymeTaqI để

cleavetheampliconfromtheplantsderivedalleleofREX1wouldresultinincorrectlyscoringahomozygousresistantplantassusceptible.

Kết quả (Việt) 2:

THẢO LUẬN chilense LA1969, thesourceofthisgene, isnotfrequentlyintrogressedalongwithTy1.Therefore, REX1markerandTy1 arenottightlylinkedtoTYLCD.Inotherwords, markerREX1isnotusefulinmarkerassistedselectionforTy1 [24]. Hơn nữa, ithasbeenreportedthatbegomovirusresistantlinesderivedfromS. habrochaites