Inducedexpressionofdefense-relatedgenesinArabidops

Inducedexpressionofdefense-relatedgenesinArabidopsisuponinfectionwithPhytophthoracapsiciPage22Page33Page44TheresearchpurposeandmeaningTheaimofthisstudywastodemonstratethatcamalexin,indoleglucosinolates(iGS)andsalicylicacid(SA)havearoleindefenseagainstP.capsici.Makeafurtherinvestigationabouttheroleofcamalexin-,iGS-andSA-relatedpathwaysinthedifferentialinteractionbetweenArabidopsisandP.capsici.Thisstudycontributestotheresearchofthemachanismaboutplant'sdefenseagainstpathogenicbacteria.Page55Selectionofpathogens(LT263,LT123)andarabidopsis(Col-0,Ler-0)plug-inoculationwithLT263andLT123onCol-0andLer-0totalRNAextractionRT-PCRreal-timePCRdataanalysisdiseasesymptomsexplainthedefensemechanismTechnologyroutePage66reseachmethods:plug-inoculation,real-timePCRexpectresults:ThearabidopsisgotinoculatedandtheDSIisCol-0/LT263＞Col-0/LT123,Ler-0/LT263＞Ler-0/LT123,Ler-0/LT263＞Col-0/LT263,Ler-0/LT123＞Col-0/LT123.Afterplug-inoculation,thelevelofgeneshavechanges,respectively.Thegenes'transcriptlevels'foldchangecausedbyLT263ishigherthanthechangecausedbyLT123.Page77Thisstudyhasshowndifferentaccession-isolatecombinationsandfornearlyallmarkergenesexpressionwashigherincompatibleinteractionsascomparedwithincompatibleinteraction.However,theexpressionprofiles,donotrevealanyobviouscorrelationbetweenexpressionlevelsanddiseasephenotype.Thedefensemechanismissocomplexthatitisnoteasytogetitclearthoughtherearesomanystudiesandreseachesonit.Soitisnecesssarytohavefurtherandcomprehensiveresearchonthemechanisminthefuture.Page88Phytophthoracapsici:•apathogenwithabroadhostrange•particularlydevastatinginvegetablecropsworldwidecompatibleinteractions:infectionincompatibleinteractions:resistancePage99Defenseresponsesactivationofdefense-relatedgenesproductionofantimicrobialcompoundsPhytophthoracapsicicaninfectarabidopsisandrevealedinteractionspecificityamongvariousaccession-isolatecombinations.Page1010LT263：colonizationofleafandroottissue,haustoriaformation,sporulationLT123:incompatbileinteractions--callosedeposition,accumulationofactiveoxygenspecies,celldeathArabidopsismutantsresistencedecrease,indicatingaroleindefense.FindadditionalsupportfortheinvolvementofthesesecondarymetabolitesindefenseagainstP.capsici.Page1111Twoarabidopsisaccessions：Col-0,Ler-0TwoP.capsiciisolates:LT263,LT123DSI:diseaseseverityindex0.2hardlyanyvisiblesymptoms3.9completecollapseofinoculatedleavesPage1212Figure1.SymptomsonArabidopsisaccessionsCol-0andLer-0afterplug-inoculationwithP.capsiciisolateLT263orLT123at3dpi.Thediseaseseverityindex(DSI)determinedisindicated.Thewhitearrowheadspointtoinoculatedleaves.Page1313Inthefourplants,Ler-0/LT263hastheseverestdecay,theDSIisLer-0/LT263＞Col-0/LT263＞Ler-0/LT123＞Col-0/LT123.Ler-0issusceptibletoLT123(DSI2.1),butevenmoresusceptibletoLT263(DSI3.9).Duringtime,thepeakinexpressioninLT263-infectedLer-0leaves(withahigherDSI)wasat24hpi,soslightlyearlierthaninLT123-infectedLer-0leaves(withalowerDSI)andinCol-0,butoverallthetranscriptchangesfollowedasimilarpatterninallinteractions.ThereisacorrelationbetweentranscriptlevelsandDSI.Page1414Page1515Figure2.TranscriptlevelsofCYP71A13,CYP71B15,CYP81F2,MYB51,PR1andPDF1.2genesduringcompatibleandincompatibleArabidopsis-P.capsiciinteractions.Four-to-five-week-oldArabidopsisleaveswereplug-inoculatedwithP.capsiciLT123(graybars)andLT263(blackbars).ThetimepointsindicatedontheX-axes(hourspostinoculation).Subsequently,totalRNAwasisolatedandusedastemplateforcDNAsynthesis.Transcriptlevelswerequantifiedbyreal-timePCRusinggene-specificprimersofwhichthesequencesareshowninthefigureandwerenormalizedwithArabidopsisActin2(F:5'-TAACTCTCCCGCTATGTATGTCGC-3';R:5'-GAGAGAAACCCTCGTAGATTGGC-3').ValuesontheY-axesareexpressedasmeanfoldchanges(±SD)relativetothetranscriptlevelinmock-inoculatedCol-0leaves(whitebars)attimepoint0whichwasarbitrarysetas1.Experimentswererepeatedtwicewithsimilarresults.Page1616Page1717InthesecompatibleinteractionstranscriptlevelsofCYP71A13werehigherthanintheincompatibleinteractionofCol-0withLT123(DSI0.2)butoveralllowerthaninthecompatibleinteractionofCol-0withLT263(DSI3.7).InLer-0basalexpressionofCYP71B15isextremelylowwhencomparedwithCol-0.IninfectedLer-0leavestheCYP71B15transcriptlevelsincreaseddramatically(morethan100-foldafter24hpi).Page1818Page1919ThereisastrongincreaseinthecompatibleinteractionforCYP81F2.ForMYB51,thedifferencesbetweentranscriptlevelsintheCol-0compatibleandincompatibleinteractionwerelesspronounced.InLer-0,MYB51transcriptlevelsinleaveswiththelowerDSI(2.1)wereoverallhigherthaninthosewithahigherDSI(3.9).Page2020Page2121InCol-0,PR1expressionwasinducedduringtheincompatibleinteractionwithP.capsiciisolateLT123withamaximumat36hpifollowedbyarapiddeclinetothebasallevel.Inthecompa-tibleinteractionwithisolateLT263,PR1transcriptaccumulationwastriggeredfaster,buttoalesserextent.InthecompatibleinteractionsofLer-0withLT123andLT263,PR1expressionwastriggeredratherfastandthefoldincreaseapproachedthelevelsobservedintheincompatibleinteractioninCol-0.Page2222Page