Bt作物的昆蟲抗藥性管理

Bt作物的昆蟲抗藥性管理2024/3/13Bt作物的昆蟲抗藥性管理IRM:whatisit?

昆蟲抗藥性管理定義 Insectresistancemanagement(IRM)isastrategytomitigatethedevelopmentofinsectsresistanttoapesticide(e.g.,resistancetoBacillusthuringiensisorBt)昆蟲抗藥性管理(IRM)是為了減輕害蟲對(duì)殺蟲劑(例如對(duì)BT)產(chǎn)生抗性而采取的一種策略.2Bt作物的昆蟲抗藥性管理IRM:whyisitimportant?

IRM的重要性MaintainingtheefficacyofBt,alow-riskpesticide,isbeneficialforthefollowingreasons:維持低風(fēng)險(xiǎn)殺蟲劑Bt的功效有如下的優(yōu)點(diǎn):BtreplaceshigherriskpesticidesBt殺蟲劑可以代替其他高風(fēng)險(xiǎn)性的殺蟲劑Lessexposureofnontargetorganismstosuperficiallyappliedpesticides降低非目標(biāo)生物暴露于殺蟲劑的可能性UseofBtcropsmayprovidegreaterprofitstofarmers,duetoreduceduseofinsecticides由于減少了殺蟲劑的使用,Bt作物可以給農(nóng)民帶來更大的收益3Bt作物的昆蟲抗藥性管理CriticalcomponentsofIRMplan

IRM計(jì)劃的重要組成成分Pestbiology害蟲生物學(xué)Dose劑量Cross-resistance抗性轉(zhuǎn)移Refuge避難所Modeling建立模型Resistancemonitoring抗性監(jiān)測Remedialaction矯正措施Complianceassurance確保規(guī)范性Growereducation種植者教育4Bt作物的昆蟲抗藥性管理Pestbiology

害蟲生物學(xué)Importantfactorsinclude:NumberofinsectgenerationsperyearHostrangeInsectmovementanddispersalpatternsMatingandovipositionalbehaviorPopulationdynamics要點(diǎn)包括:每年害蟲繁殖的代數(shù)宿主的范圍害蟲移動(dòng)和分布的模式交配和產(chǎn)卵行為種群動(dòng)態(tài)5Bt作物的昆蟲抗藥性管理Pestbiology:anexample

害蟲生物學(xué)舉例Europeancornborer(ECB),Ostrinianubilalis1-4generationsperyearPolyphagous(preferscorn)Movement:Larvae-canmovefromplant-to-plantwithinafieldAdults-mostlylocalmovement,butsomelongdistancemigratorymovementcanoccur歐洲玉米螟(ECB)每年繁殖1-4代雜食性(偏好玉米)移動(dòng)幼蟲可以在同一田地內(nèi)不同植株上移動(dòng)成蟲大部分在本地活動(dòng),但也有可能進(jìn)行長距離遷移Female雌性Male雄性lateinstars晚期幼蟲ECB6Bt作物的昆蟲抗藥性管理Dose劑量Dose=theamountoftoxinexpressedovertimebyatransgeniccrop,relativetothesusceptibilityofatargetpest;canbedeterminedthroughfieldefficacytrialsorlaboratorybioassays劑量=轉(zhuǎn)基因作物在一定時(shí)間內(nèi)表達(dá)的毒素的量,和目標(biāo)害蟲的敏感性相關(guān);通常由田間功效實(shí)驗(yàn)或?qū)嶒?yàn)室生物測試所決定.Highdose=atleast25xtheamountoftoxinneededtokillallsusceptibletargetinsects;preferredoverlowdoseeventsforrefuge-basedIRMstrategies高劑量=至少為殺死所有敏感目標(biāo)害蟲劑量的25倍;在以避難所為基礎(chǔ)的昆蟲抗性管理策略中，使用高劑量遺傳事件體要比低劑量遺傳事件體好7Bt作物的昆蟲抗藥性管理Doseassumptions

劑量假設(shè)Threegenotypesforresistance/susceptibility(SS,rS,rr)Resistance(rr)isrecessiveandrareRefugesuppliesSS(homozygoussusceptible)genotypeRandommating:rrxSS→rSrSxSS→rSorSSSSandrSsusceptibletohighdose三種抗性/敏感性基因型(SS,rS,rr)抗性基因(rr)是隱性的,少見的安全基因型SS(純合敏感)隨機(jī)交配:rrxSS→rSrSxSS→rSorSSSS和rS對(duì)高劑量敏感LC500100低高8Bt作物的昆蟲抗藥性管理Doselevels:someexamples

關(guān)于劑量水平的一些例子Lepidopteran-activecorn(Cry1Ab&Cry1F):HighdoseEuropeancornborer(ECB),OstrinianubilalisSouthwesterncornborer(SWCB)DiatraeacrambidoidesNon-highdoseCornearworm(CEW),Helicoverpazea鱗翅目敏感玉米(Cry1Ab&Cry1F):高劑量歐洲玉米螟(ECB),Ostrinianubilalis西南玉米螟(SWCB)Diatraeacrambidoides非高劑量玉米棉鈴蟲(CEW),HelicoverpazeaWCRfemalemalelateinstarsECB9Bt作物的昆蟲抗藥性管理Doselevels:someexamples

關(guān)于劑量水平的一些例子Rootworm-activecorn(Cry3Bb1,Cry34/35,mCry3A)Non-highdoseWesterncornrootworm(WCR),DiabroticavirgiferavirgiferaNortherncornrootworm(NCR),D.barberiMexicancornrootworm(MCR),D.virgiferazeaSecondarypestsNon-highdoseforsomepests根蟲敏感玉米(Cry3Bb1,Cry34/35,mCry3A)非高劑量西部玉米根蟲(WCR),Diabroticavirgiferavirgifera北部玉米根蟲(NCR),D.barberi墨西哥玉米根蟲(MCR),D.virgiferazea次級(jí)害蟲非高劑量WCRfemalemalelateinstarsECB10Bt作物的昆蟲抗藥性管理Cross-resistance

抗性轉(zhuǎn)移WhenresistancetoasingleBttoxinconferspestresistancetoaclusterofrelatedtoxinsFactorsaffectingcross-resistanceinclude:Similarity/dissimilarityofcommercializedtoxinsUseofsingletoxinversusmultipletoxinsLevelofresistanceinaninsectpopulation害蟲對(duì)單一Bt蛋白的抗性使得害蟲對(duì)其他一系列相關(guān)毒素都產(chǎn)生抗性影響抗性轉(zhuǎn)移的因素包括:商品用毒素的異同點(diǎn)單一毒素和復(fù)合毒素的使用昆蟲種群的抗性水平11Bt作物的昆蟲抗藥性管理Cross-resistance:anexample(抗性轉(zhuǎn)移:舉例說明)BindingsitediagramforEuropeancornborer(歐洲玉米螟結(jié)合位點(diǎn)簡圖)Cry1AbCry1FCry1Ac220KDaCadherin154KDaAPN145/167KDaAPNOtherEuropeancornborer(basedonHua,G.,Masson,L.,Jurat-Fuentes,J.L.,Schwab,G.,Adang,M.J.2001.BindinganalysesofBacillusthuringiensisCryd-endotoxinsusingbrushbordermembranevesiclesofOstrinianubilalis.Appl.Env.Microbiol.67:872-879)(其他)12Bt作物的昆蟲抗藥性管理Refuge避難所AnyhostplantthatdoesnotproduceBttoxinandhasnotbeentreatedwithconventionalBtformulations(maybetreatedwithnon-Btinsecticide)任何不產(chǎn)生Bt毒素并且也未經(jīng)常規(guī)Bt殺蟲劑處理過的宿主植物(可能經(jīng)非Bt殺蟲劑處理過)Enablesmatingbetweenresistantandsusceptibleadults,resultinginproductionofsusceptibleoffspring抗性和敏感性成熟植株雜交可以產(chǎn)生敏感性的后代13Bt作物的昆蟲抗藥性管理Refugeoptions 避難所的選擇Structuredrefuge=specifiedsize,locationinrelationtoBtfield,andcrop/plantcompositionCommunity-basedrefuge=neighboringgrowersestablishsharedstructuredrefugeUnstructuredornaturalrefuge=useofalternativehostplants/cropsinplaceofdefinedrefuge結(jié)構(gòu)避難所=特定大小,并且位置和Bt植物種植區(qū)有一定關(guān)系的區(qū)域,此區(qū)域既有農(nóng)作物,又有植被以社區(qū)為基礎(chǔ)的避難所=相鄰的種植者建立的一種共享的結(jié)構(gòu)避難所非結(jié)構(gòu)或稱天然避難所=用一種寄主植物和作物互相交替種植的模式來代替人為限定的避難所模式14Bt作物的昆蟲抗藥性管理Refugeoptions 避難所的選擇Seedbagmix=BtseedbagscontainBtseedandnon-Btseed(e.g.,80%Bt,20%non-Bt);seedmaybebaggedseparatelyormixedtogetherRegionallimit=national/regionalgovernmentenforcedlimitonBtseedsales(e.g.,80%indefinedregion)混裝種袋=在這種含Bt種子的袋子中既含有Bt種子,也含有非Bt種子(例如:80%Bt種子,20%非Bt種子),種子可以先按小袋分裝好再混和,也可以直接混在一起.區(qū)域限制=國家或地方政府對(duì)Bt種子的買賣進(jìn)行嚴(yán)格限制(例如:在一定區(qū)域內(nèi)，只允許80%的Bt種子的買賣)15Bt作物的昆蟲抗藥性管理SeedmixBlockIn-fieldstrips田地內(nèi)的條帶模式Internalblock(s)內(nèi)部種植模式Border(block)周邊種植模式Structuredrefugeoptions

結(jié)構(gòu)避難所的選擇Externalblock外部種植模式種子混和16Bt作物的昆蟲抗藥性管理Otherrefugeoptions

其他避難所選擇Communityrefuge社區(qū)避難所模式80%Bt

seedcorn玉米種子20%non-Bt

seedcorn玉米種子Naturalrefuge天然避難所BtcottonBt棉花w/TBWSoybean大豆Tobacco煙草Tobaccobudworm,煙草蚜蟲Heliothisvirescens

17Bt作物的昆蟲抗藥性管理Btcornrefugespecifications:anexample

Bt玉米避難所規(guī)范示例20%refugerequiredincornbelt;50%refugerequiredincorn/cottonregionStructuredrefugeisrequired.Refugesmaybeplantedinoneofthefollowingdesigns:In-fieldstrips(4-6rows)Blocks(internalorexternal)Refugerequirementsarethesameforlepidopteranandcoleopteranactiveproducts在Bt玉米田中20%為避難所,在玉米/棉花田中則為50%結(jié)構(gòu)性避難所是必須的.避難所可以按如下的設(shè)計(jì)來耕作:田地內(nèi)條帶(4-6行)內(nèi)部或外部田塊18Bt作物的昆蟲抗藥性管理Modeling模擬Usefultoolforpredictingthelikelihoodofresistance,forevaluatingthedurabilityofIRMstrategies,andforhelpingtofocusdataneeds.Modelcomponentsinclude:Biologicalinformation(pestbiology,populationdynamics)Genetics(R-alleledominance/frequency,crossresistance)Operationalaspects(dose,single/stackedtoxin(s),refuge)建立模型是預(yù)測抗藥可能性,評(píng)價(jià)IRM策略持久性和幫助調(diào)整數(shù)據(jù)需求的一種有效方法.模型包括以下組成成分:生物信息(害蟲生物學(xué),種群動(dòng)態(tài))遺傳學(xué)(R-等位基因顯性/頻率,抗性轉(zhuǎn)移)運(yùn)行情況(劑量,單一的/疊加的毒劑,避難所)19Bt作物的昆蟲抗藥性管理Resistancemonitoring

抗性監(jiān)測CanhelptoprolongtheefficacyofaninsectresistantcropDesignedtodetectresistance2-3yearsbeforefieldfailureTargetpestsamplingconsistsof:Growerreportsofunexpectedpestdamageininsect-protectedcropfieldsRandompopulationsampling:SamplingbasedonpestprevalenceinregionSamplingtarget:numberofinsectsneededtodetermineresistanceatp<0.01

可以延長抗蟲作物的功效可以在失效前監(jiān)測抗性2-3年目標(biāo)害蟲取樣包括:種植者在抗蟲作物區(qū)域內(nèi)由害蟲造成的意外損失報(bào)告隨機(jī)種群取樣:害蟲流行區(qū)域取樣取樣目標(biāo):用來確定抗性所需的害蟲數(shù)量(p<0.01)20Bt作物的昆蟲抗藥性管理Resistancemonitoring(cont.)

抗性監(jiān)測(續(xù))Bioassaysareusedtodetectpotentialresistanceinsampledpopulations.Assaysinclude:Pestsusceptibility(LC50)DiscriminatingDose(LC99)F2screenConfirmationstudiesareusedtoverifyresistance.Questionsinclude:Istherefieldfailure?Istheinsectresistancetraitexpressed?Isinsectresistancetraitinherited?用生物鑒定來檢測樣品種群中的潛在抗性.生物鑒定包括:害蟲敏感性鑒定(LC50)差異劑量(LC99)F2篩選確認(rèn)研究用來核實(shí)抗性.包括:區(qū)域失效了么?抗性特征表達(dá)了么?抗性性可遺傳么?21Bt作物的昆蟲抗藥性管理Resistancemonitoring:positivehitsforBtcornintheUS?抗性監(jiān)測:美國Bt玉米正采樣數(shù)In2001,mortalityforoneEuropeancornborer(ECB)population(Kandiyohi,MN)was<99%inCry1AbdiscriminatingdoseassayFollow-uptestswithBtplantmaterialrevealedthatpopulationwasnotfieldresistantNofieldresistanceconfirmedforanymonitoredBtcornpest2001年在Cry1Ab不同劑量分析中,歐洲玉米螟種群的死亡率小于99%Bt作物的后續(xù)測試表明種群并沒有田間抗藥性被監(jiān)測的Bt玉米害蟲沒有被證實(shí)產(chǎn)生田間抗藥性22Bt作物的昆蟲抗藥性管理Remedialactionplan

矯正措施 Ifresistanceisconfirmedthroughresistancemonitoring,aremedialactionplanisimplementedtocontainorslowthespreadofresistantpestpopulations

如果抗性監(jiān)測確認(rèn)了抗藥性,矯正措施可以減緩害蟲種群抗藥性的傳播23Bt作物的昆蟲抗藥性管理Remedialactionplan:anexample

矯正措施舉例EPA’splanincludes:MandatoryreportingofsuspectedresistanceUseofalternatecontrolmeasuresinaffectedareasIncreasedresistancemonitoringSuspensionofBtcropsalesinaffectedareasInvestigationofcauseofresistance美國環(huán)保局措施包括:強(qiáng)制要求對(duì)有懷疑的抗藥性表現(xiàn)上報(bào)在有影響區(qū)域使用其他管理措施增強(qiáng)抗性監(jiān)測在被影響區(qū)域終止Bt玉米銷售對(duì)抗藥性原因進(jìn)行調(diào)查24Bt作物的昆蟲抗藥性管理Complianceassurance

確保規(guī)范性

CompliancemeasuresimplementedtoensurethatgrowerscomplywithapprovedIRMprogram規(guī)范操作可以確保種植者按照害蟲抗藥性管理規(guī)則執(zhí)行耕種操作.25Bt作物的昆蟲抗藥性管理Complianceassurance:anexample

確保規(guī)范性舉例EPArequiresregistrantstoimplementthefollowingmeasures:ContractsaffirminggroweragreementtocomplywithapprovedIRMstrategy3rdpartygrowersurveysofIRMimplementationOn-farmfieldvisitstoverifyIRMimplementationTipsandcomplaintsonnon-compliersSuspensionofseedaccessfornon-compliers美國環(huán)保局規(guī)定登記者必須實(shí)施以下方法:合同規(guī)定種植者必須遵守IRM策略第三方對(duì)IRM執(zhí)行情況進(jìn)行調(diào)查田間觀察以確定IRM的執(zhí)行情況揭發(fā)和投訴不遵守規(guī)則的種植者對(duì)不遵守規(guī)則的種植者終止種子供應(yīng)26Bt作物的昆蟲抗藥性管理Growereducation

種植者教育

EducationabouttheneedforIRM,howtoimplementrequirements,andgrowerresponsibilityincomplyingwithIRMrequirements對(duì)IRM策略的必要性,怎樣完成要求,和種植者對(duì)完成IRM要求所擔(dān)負(fù)的責(zé)任進(jìn)行教育27Bt作物的昆蟲抗藥性管理SummaryofEPA’sIRMrequirementsforlepidopteran-activeBtcorn

美國環(huán)保局對(duì)鱗翅目昆蟲敏感的Bt玉米IRM要求概述20%refugeincornbelt;50%refugeincottonbeltStructuredrefugerequired.Refugesplantedinoneofthefollowingdesigns:in-fieldstrips(4-6rows)blocks(internalorexternal)Industry-widecollaborationoncompliancesurveys在玉米種植帶中20%為避難所;在棉花種植帶中為50%結(jié)構(gòu)性避難所是必需的.避難所種植需為如下設(shè)計(jì)中的一種:田間條帶(4-6行)田塊(內(nèi)部或外部)廣泛合作開展規(guī)范性調(diào)查28Bt作物的昆蟲抗藥性管理SummaryofEPA’sIRMrequirementsforlepidopteran-activeBtcorn(cont.)

對(duì)鱗翅目昆蟲敏感的Bt玉米IRM要求概述(續(xù))Industry-wideuniformityof:GroweragreementsGrowertrainingImplementationoftipsandcomplaints以下行為保持高度一致性:種植者協(xié)議種植者培訓(xùn)監(jiān)測和投訴的實(shí)施29Bt作物的昆蟲抗藥性管理SummaryofEPA’sIRMrequirementsforlepidopteran-activeBtcorn(cont.)對(duì)鱗翅目昆蟲敏感的Bt玉米IRM要求概述(續(xù))Annualreportingrequirements:－Complianceassurance(e.g.,surveys,growercontracts)－Changestogrowereducation－Resistancemonitoringdata－Salesdata年度報(bào)告需要:規(guī)范性確認(rèn)材料(例如調(diào)查,種植者合同)種植者教育的變化抗性監(jiān)測數(shù)據(jù)銷售數(shù)據(jù)30Bt作物的昆蟲抗藥性管理DatasourcesforEPA’sIRMprogram

美國環(huán)保局IRM項(xiàng)目的數(shù)據(jù)來源PublishedscientificliteratureIndustrysubmissionsExperts(academia,government,industry)Meetings(advisorypanels,workshops,ESA,NC205,NC46)Fieldvisits已出版的科學(xué)文獻(xiàn)工業(yè)企業(yè)的報(bào)告專家(學(xué)術(shù)界,政府,工業(yè)界)會(huì)議(顧問團(tuán),研討會(huì),ESA,NC205,NC46)田間觀察31Bt作物的昆蟲抗藥性管理KeystosuccessatEPA

美國環(huán)保局(EPA)取得成功的關(guān)鍵EPAisresponsivetonewscientificinformationEPAseeksscientificinputfromstateandfederalagencies,academicexperts,andpublicinterestgroupsEPA對(duì)最