B作物的昆蟲抗藥性管理

InsectResistanceManagementforBtCrops

Bt作物的昆蟲抗藥性管理TessaMilofsky,M.S.andSharleneMatten,Ph.D.泰莎.米洛夫斯基碩士沙利恩.馬頓博士U.S.EnvironmentalProtectionAgencyOfficeofPesticidePrograms美國環(huán)保局殺蟲劑項目辦公室1IRM:whatisit?

昆蟲抗藥性管理定義

Insectresistancemanagement(IRM)isastrategytomitigatethedevelopmentofinsectsresistanttoapesticide(e.g.,resistancetoBacillusthuringiensisorBt)

昆蟲抗藥性管理(IRM)是為了減輕害蟲對殺蟲劑(例如對BT)產(chǎn)生抗性而采取的一種策略.2IRM:whyisitimportant?

IRM的重要性MaintainingtheefficacyofBt,alow-riskpesticide,isbeneficialforthefollowingreasons:維持低風險殺蟲劑Bt的功效有如下的優(yōu)點:BtreplaceshigherriskpesticidesBt殺蟲劑可以代替其他高風險性的殺蟲劑Lessexposureofnontargetorganismstosuperficiallyappliedpesticides降低非目標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3CriticalcomponentsofIRMplan

IRM計劃的重要組成成分Pestbiology害蟲生物學Dose劑量Cross-resistance抗性轉移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4Pestbiology

害蟲生物學Importantfactorsinclude:NumberofinsectgenerationsperyearHostrangeInsectmovementanddispersalpatternsMatingandovipositionalbehaviorPopulationdynamics要點包括:每年害蟲繁殖的代數(shù)宿主的范圍害蟲移動和分布的模式交配和產(chǎn)卵行為種群動態(tài)5Pestbiology:anexample

害蟲生物學舉例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)移動幼蟲可以在同一田地內(nèi)不同植株上移動成蟲大部分在本地活動,但也有可能進行長距離遷移Female雌性Male雄性lateinstars晚期幼蟲ECB6Dose劑量Dose=theamountoftoxinexpressedovertimebyatransgeniccrop,relativetothesusceptibilityofatargetpest;canbedeterminedthroughfieldefficacytrialsorlaboratorybioassays劑量=轉基因作物在一定時間內(nèi)表達的毒素的量,和目標害蟲的敏感性相關;通常由田間功效實驗或?qū)嶒炇疑餃y試所決定.Highdose=atleast25xtheamountoftoxinneededtokillallsusceptibletargetinsects;preferredoverlowdoseeventsforrefuge-basedIRMstrategies高劑量=至少為殺死所有敏感目標害蟲劑量的25倍;在以避難所為基礎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7Doseassumptions

劑量假設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)隨機交配:rrxSS→rSrSxSS→rSorSSSS和rS對高劑量敏感LC500100低高8Doselevels:someexamples

關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),HelicoverpazeaWCRfemalemalelateinstarsECB9Doselevels:someexamples

關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次級害蟲非高劑量WCRfemalemalelateinstarsECB10Cross-resistance抗性轉移WhenresistancetoasingleBttoxinconferspestresistancetoaclusterofrelatedtoxinsFactorsaffectingcross-resistanceinclude:Similarity/dissimilarityofcommercializedtoxinsUseofsingletoxinversusmultipletoxinsLevelofresistanceinaninsectpopulation害蟲對單一Bt蛋白的抗性使使得害蟲對其其他一系列相相關毒素都產(chǎn)產(chǎn)生抗性影響抗性轉移移的因素包括括:商品用毒素的的異同點單一毒素和復復合毒素的使使用昆蟲種群的抗抗性水平11Cross-resistance:anexample(抗性轉移:舉舉例說明)BindingsitediagramforEuropeancornborer(歐洲玉米螟結結合位點簡圖圖)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)12Refuge避難所AnyhostplantthatdoesnotproduceBttoxinandhasnotbeentreatedwithconventionalBtformulations(maybetreatedwithnon-Btinsecticide)任何不產(chǎn)生Bt毒素并且也未未經(jīng)常規(guī)Bt殺蟲劑處理過過的宿主植物物(可能經(jīng)非非Bt殺蟲劑處理過過)Enablesmatingbetweenresistantandsusceptibleadults,resultinginproductionofsusceptibleoffspring抗性和敏感性性成熟植株雜雜交可以產(chǎn)生生敏感性的后后代13Refugeoptions避難所的選擇擇Structuredrefuge=specifiedsize,locationinrelationtoBtfield,andcrop/plantcompositionCommunity-basedrefuge=neighboringgrowersestablishsharedstructuredrefugeUnstructuredornaturalrefuge=useofalternativehostplants/cropsinplaceofdefinedrefuge結構避難所=特定大小,并且位置和和Bt植物種植區(qū)有有一定關系的的區(qū)域,此區(qū)區(qū)域既有農(nóng)作作物,又有植植被以社區(qū)為基礎礎的避難所=相鄰的種植植者建立的一一種共享的結結構避難所非結構或稱天天然避難所=用一種寄主主植物和作物物互相交替種種植的模式來來代替人為限限定的避難所所模式14Refugeoptions避難所的選擇擇Seedbagmix=BtseedbagscontainBtseedandnon-Btseed(e.g.,80%Bt,20%non-Bt);seedmaybebaggedseparatelyormixedtogetherRegionallimit=national/regionalgovernmentenforcedlimitonBtseedsales(e.g.,80%indefinedregion)混裝種袋=在在這種含Bt種子的袋子中中既含有Bt種子,也含有有非Bt種子(例如:80%Bt種子,20%非Bt種子),種種子可以先按按小袋分裝好好再混和,也也可以直接混混在一起.區(qū)域限限制=國家家或地地方政政府對對Bt種子的的買賣賣進行行嚴格格限制制(例例如:在在一定定區(qū)域域內(nèi)，，只允允許80%的Bt種子的的買賣賣)15SeedmixBlockIn-fieldstrips田地內(nèi)內(nèi)的條條帶模模式Internalblock(s)內(nèi)部種種植模模式Border(block)周邊種種植模模式Structuredrefugeoptions結構避避難所所的選選擇Externalblock外部種種植模模式種子混混和16Otherrefugeoptions其他避避難所所選擇擇Communityrefuge社區(qū)避避難所所模式式80%Btseedcorn玉米種種子20%non-Btseedcorn玉米種種子Naturalrefuge天然避避難所所BtcottonBt棉花w/TBWSoybean大豆Tobacco煙草Tobaccobudworm,煙草蚜蚜蟲Heliothisvirescens17Btcornrefugespecifications:anexampleBt玉米米避避難難所所規(guī)規(guī)范范示示例例20%refugerequiredincornbelt;50%refugerequiredincorn/cottonregionStructuredrefugeisrequired.Refugesmaybeplantedinoneofthefollowingdesigns:In-fieldstrips(4-6rows)Blocks(internalorexternal)Refugerequirementsarethesameforlepidopteranandcoleopteranactiveproducts在Bt玉米米田田中中20%為為避難難所所,在在玉玉米米/棉棉花花田田中中則則為為50%結構構性性避難難所所是必必須須的的.避難難所所可以以按按如如下下的的設設計計來來耕耕作作:田地地內(nèi)內(nèi)條條帶帶(4-6行行)內(nèi)部部或或外外部部田田塊塊18Modeling模擬擬Usefultoolforpredictingthelikelihoodofresistance,forevaluatingthedurabilityofIRMstrategies,andforhelpingtofocusdataneeds.Modelcomponentsinclude:Biologicalinformation(pestbiology,populationdynamics)Genetics(R-alleledominance/frequency,crossresistance)Operationalaspects(dose,single/stackedtoxin(s),refuge)建立立模模型型是是預預測測抗抗藥藥可可能能性性,評評價價IRM策略略持持久久性性和和幫幫助助調(diào)調(diào)整整數(shù)數(shù)據(jù)據(jù)需需求求的的一一種種有有效效方方法法.模模型型包包括括以以下下組組成成成成分分:生物信息息(害蟲蟲生物學學,種群群動態(tài))遺傳學(R-等位基因因顯性/頻率,抗性性轉移)運行情況況(劑量量,單一一的/疊疊加的毒毒劑,避避難所)19Resistancemonitoring抗性監(jiān)測測CanhelptoprolongtheefficacyofaninsectresistantcropDesignedtodetectresistance2-3yearsbeforefieldfailureTargetpestsamplingconsistsof:Growerreportsofunexpectedpestdamageininsect-protectedcropfieldsRandompopulationsampling:SamplingbasedonpestprevalenceinregionSamplingtarget:numberofinsectsneededtodetermineresistanceatp<0.01可以延長長抗蟲作作物的功功效可以在失失效前監(jiān)監(jiān)測抗性性2-3年目標害蟲蟲取樣包包括:種植者在在抗蟲作作物區(qū)域域內(nèi)由害害蟲造成成的意外外損失報報告隨機種群群取樣:害蟲流行行區(qū)域取取樣取樣目標標:用來來確定抗抗性所需需的害蟲蟲數(shù)量(p<0.01)20Resistancemonitoring(cont.)抗性監(jiān)測測(續(xù))Bioassaysareusedtodetectpotentialresistanceinsampledpopulations.Assaysinclude:Pestsusceptibility(LC50)DiscriminatingDose(LC99)F2screenConfirmationstudiesareusedtoverifyresistance.Questionsinclude:Istherefieldfailure?Istheinsectresistancetraitexpressed?Isinsectresistancetraitinherited?用生物鑒鑒定來檢檢測樣品品種群中中的潛在在抗性.生物物鑒定包包括:害蟲敏感感性鑒定定(LC50)差異劑量量(LC99)F2篩選確認研究究用來核核實抗性性.包括括:區(qū)域失效效了么?抗性特征征表達了了么?抗性性可可遺傳么么?21Resistancemonitoring:positivehitsforBtcornintheUS?抗性監(jiān)監(jiān)測:美美國Bt玉米正正采樣樣數(shù)In2001,mortalityforoneEuropeancornborer(ECB)population(Kandiyohi,MN)was<99%inCry1AbdiscriminatingdoseassayFollow-uptestswithBtplantmaterialrevealedthatpopulationwasnotfieldresistantNofieldresistanceconfirmedforanymonitoredBtcornpest2001年在Cry1Ab不同劑劑量分分析中中,歐歐洲洲玉米米螟種種群的的死亡亡率小小于99%Bt作物的的后續(xù)續(xù)測試試表明明種群群并沒沒有田田間抗抗藥性性被監(jiān)測測的Bt玉米害害蟲沒沒有被被證實實產(chǎn)生生田間間抗藥藥性22Remedialactionplan矯正措措施Ifresistanceisconfirmedthroughresistancemonitoring,aremedialactionplanisimplementedtocontainorslowthespreadofresistantpestpopulations如果抗抗性監(jiān)監(jiān)測確確認了了抗藥藥性,矯矯正措措施可可以減減緩害害蟲種種群抗抗藥性性的傳傳播23Remedialactionplan:anexample矯正措措施舉舉例EPA’splanincludes:MandatoryreportingofsuspectedresistanceUseofalternatecontrolmeasuresinaffectedareasIncreasedresistancemonitoringSuspensionofBtcropsalesinaffectedareasInvestigationofcauseofresistance美國環(huán)環(huán)保局局措施施包括括:強制要要求對對有懷懷疑的的抗藥藥性表表現(xiàn)上上報在有影影響區(qū)區(qū)域使使用其其他管管理措措施增強抗抗性監(jiān)監(jiān)測在被影影響區(qū)區(qū)域終終止Bt玉米銷銷售對抗藥藥性原原因進進行調(diào)調(diào)查24Complianceassurance確保規(guī)規(guī)范性性CompliancemeasuresimplementedtoensurethatgrowerscomplywithapprovedIRMprogram規(guī)范操操作可可以確確保種種植者者按照照害蟲蟲抗藥藥性管管理規(guī)規(guī)則執(zhí)執(zhí)行耕耕種操操作.25Complianceassurance:anexample確保規(guī)規(guī)范性性舉例例EPArequiresregistrantstoimplementthefollowingmeasures:ContractsaffirminggroweragreementtocomplywithapprovedIRMstrategy3rdpartygrowersurveysofIRMimplementationOn-farmfieldvisitstoverifyIRMimplementationTipsandcomplaintsonnon-compliersSuspensionofseedaccessfornon-compliers美國環(huán)環(huán)保局局規(guī)定定登記記者必必須實實施以以下方方法:合同規(guī)規(guī)定種種植者者必須須遵守守IRM策略第三方方對IRM執(zhí)行情情況進進行調(diào)調(diào)查田間觀觀察以以確定定IRM的執(zhí)行行情況況揭發(fā)和和投訴訴不遵遵守規(guī)規(guī)則的的種植植者對不遵遵守規(guī)規(guī)則的的種植植者終終止種種子供供應26Growereducation種植者者教育育EducationabouttheneedforIRM,howtoimplementrequirements,andgrowerresponsibilityincomplyingwithIRMrequirements對IRM策略的必要要性,怎怎樣完成要要求,和和種植者對對完成IRM要求所擔負負的責任進進行教育27SummaryofEPA’sIRMrequirementsforlepidopteran-activeBtcorn美國環(huán)保局局對鱗翅目目昆蟲敏感感的Bt玉米IRM要求概述20%refugeincornbelt;50%refugeincottonbeltStructuredrefugerequired.Refugesplantedinoneofthefollowingdesigns:in-fieldstrips(4-6rows)blocks(internalorexternal)Industry-widecollaborationoncompliancesurveys在玉米種植植帶中20%為避難難所;在在棉花種植植帶中為50%結構性避難難所是必需需的.避難難所種植需需為如下設設計中的一一種:田間條帶(4-6行行)田塊(內(nèi)部部或外部)廣泛合作開開展規(guī)范性性調(diào)查28SummaryofEPA’sIRMrequirementsforlepidopteran-activeBtcorn(cont.)對鱗翅目昆昆蟲敏感的的Bt玉米IRM要求概述(續(xù))Industry-wideuniformityof:GroweragreementsGrowertrainingImplementationoftipsandcomplaints以下行為保保持高度一一致性:種植者協(xié)議議種植者培訓訓監(jiān)測和投訴訴的實施29SummaryofEPA’sIRMrequirementsforlepidopteran-activeBtcorn(cont.)對鱗翅目昆昆蟲敏感的的Bt玉米IRM要求概述(續(xù))Annualreportingrequirements:－Complianceassurance(e.g.,surveys,growercontracts)－Changestogrowereducation－Resistancemonitoringdata－Salesdata年度報告需需要:規(guī)范性確認認材料(例例如調(diào)查,種植者合合同)種植者教育育的變化抗性監(jiān)測數(shù)數(shù)據(jù)銷售數(shù)據(jù)30DatasourcesforEPA’’sIRMprogram美國環(huán)保局局IRM項目的數(shù)據(jù)據(jù)來源PublishedscientificliteratureIndustrysubmissionsExperts(academia,government,industry)Meetings(advisorypanels,workshops,ESA,NC205,NC46)Fieldvisits已出出版版的的科科學學文文獻獻工業(yè)業(yè)企企業(yè)業(yè)的的報報告告專家家(學學術術界界,政政府府,工工業(yè)業(yè)界界)會議議(顧顧問問團團,研研討討會會,ESA,NC205,NC46)田間間觀觀察察31KeystosuccessatEPA美國國環(huán)環(huán)保保局局(EPA)取得得成成功功的的關關鍵鍵EPAisresponsivetonewscientificinformationEPAseeksscientificinputfromstateandfederalagencies,academicexperts,andpublicinterestgroupsEPA對最最新新的的科科技技信信息息反反應應積積極極EPA從各各州州和和聯(lián)聯(lián)邦邦的的政政府府部部門門,學學術術專專家家和和公公眾眾團團體體中中尋尋求求科科技技力力量量32KeystosuccessatEPA美國國環(huán)環(huán)保保局局(EPA)取得得成成功功的的關關鍵鍵Conditional(time-limited)registrationsenableEPAtoadaptIRMrequirementsovertimeEPAnegotiatesregulatorychangeswithregistrantsandgrowerorganizations有時時間間限限制制的的注注冊冊可可以以使使EPA適應應IRM隨著著時時間間變變化化而而產(chǎn)產(chǎn)生生的的新新要要求求EPA經(jīng)常常與