B作物的昆虫抗药性管理

InsectResistanceManagementforBtCrops

Bt作物的昆虫抗药性管理TessaMilofsky,M.S.andSharleneMatten,Ph.D.泰莎.米洛夫斯基硕士沙利恩.马顿博士U.S.EnvironmentalProtectionAgencyOfficeofPesticidePrograms美国环保局杀虫剂项目办公室1IRM:whatisit?

昆虫抗药性管理定义

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

昆虫抗药性管理(IRM)是为了减轻害虫对杀虫剂(例如对BT)产生抗性而采取的一种策略.2IRM:whyisitimportant?

IRM的重要性MaintainingtheefficacyofBt,alow-riskpesticide,isbeneficialforthefollowingreasons:维持低风险杀虫剂Bt的功效有如下的优点:BtreplaceshigherriskpesticidesBt杀虫剂可以代替其他高风险性的杀虫剂Lessexposureofnontargetorganismstosuperficiallyappliedpesticides降低非目标生物暴露于杀虫剂的可能性UseofBtcropsmayprovidegreaterprofitstofarmers,duetoreduceduseofinsecticides由于减少了杀虫剂的使用,Bt作物可以给农民带来更大的收益3CriticalcomponentsofIRMplan

IRM计划的重要组成成分Pestbiology害虫生物学Dose剂量Cross-resistance抗性转移Refuge避难所Modeling建立模型Resistancemonitoring抗性监测Remedialaction矫正措施Complianceassurance确保规范性Growereducation种植者教育4Pestbiology

害虫生物学Importantfactorsinclude:NumberofinsectgenerationsperyearHostrangeInsectmovementanddispersalpatternsMatingandovipositionalbehaviorPopulationdynamics要点包括:每年害虫繁殖的代数宿主的范围害虫移动和分布的模式交配和产卵行为种群动态5Pestbiology:anexample

害虫生物学举例Europeancornborer(ECB),Ostrinianubilalis1-4generationsperyearPolyphagous(preferscorn)Movement:Larvae-canmovefromplant-to-plantwithinafieldAdults-mostlylocalmovement,butsomelongdistancemigratorymovementcanoccur欧洲玉米螟(ECB)每年繁殖1-4代杂食性(偏好玉米)移动幼虫可以在同一田地内不同植株上移动成虫大部分在本地活动,但也有可能进行长距离迁移Female雌性Male雄性lateinstars晚期幼虫ECB6Dose剂量Dose=theamountoftoxinexpressedovertimebyatransgeniccrop,relativetothesusceptibilityofatargetpest;canbedeterminedthroughfieldefficacytrialsorlaboratorybioassays剂量=转基因作物在一定时间内表达的毒素的量,和目标害虫的敏感性相关;通常由田间功效实验或实验室生物测试所决定.Highdose=atleast25xtheamountoftoxinneededtokillallsusceptibletargetinsects;preferredoverlowdoseeventsforrefuge-basedIRMstrategies高剂量=至少为杀死所有敏感目标害虫剂量的25倍;在以避难所为基础的昆虫抗性管理策略中，使用高剂量遗传事件体要比低剂量遗传事件体好7Doseassumptions

剂量假设Threegenotypesforresistance/susceptibility(SS,rS,rr)Resistance(rr)isrecessiveandrareRefugesuppliesSS(homozygoussusceptible)genotypeRandommating:rrxSS→rSrSxSS→rSorSSSSandrSsusceptibletohighdose三种抗性/敏感性基因型(SS,rS,rr)抗性基因(rr)是隐性的,少见的安全基因型SS(纯合敏感)随机交配:rrxSS→rSrSxSS→rSorSSSS和rS对高剂量敏感LC500100低高8Doselevels:someexamples

关于剂量水平的一些例子Lepidopteran-activecorn(Cry1Ab&Cry1F):HighdoseEuropeancornborer(ECB),OstrinianubilalisSouthwesterncornborer(SWCB)DiatraeacrambidoidesNon-highdoseCornearworm(CEW),Helicoverpazea鳞翅目敏感玉米(Cry1Ab&Cry1F):高剂量欧洲玉米螟(ECB),Ostrinianubilalis西南玉米螟(SWCB)Diatraeacrambidoides非高剂量玉米棉铃虫(CEW),HelicoverpazeaWCRfemalemalelateinstarsECB9Doselevels:someexamples

关于剂量水平的一些例子Rootworm-activecorn(Cry3Bb1,Cry34/35,mCry3A)Non-highdoseWesterncornrootworm(WCR),DiabroticavirgiferavirgiferaNortherncornrootworm(NCR),D.barberiMexicancornrootworm(MCR),D.virgiferazeaSecondarypestsNon-highdoseforsomepests根虫敏感玉米(Cry3Bb1,Cry34/35,mCry3A)非高剂量西部玉米根虫(WCR),Diabroticavirgiferavirgifera北部玉米根虫(NCR),D.barberi墨西哥玉米根虫(MCR),D.virgiferazea次级害虫非高剂量WCRfemalemalelateinstarsECB10Cross-resistance抗性转移WhenresistancetoasingleBttoxinconferspestresistancetoaclusterofrelatedtoxinsFactorsaffectingcross-resistanceinclude:Similarity/dissimilarityofcommercializedtoxinsUseofsingletoxinversusmultipletoxinsLevelofresistanceinaninsectpopulation害虫对单一Bt蛋白的抗性使使得害虫对其其他一系列相相关毒素都产产生抗性影响抗性转移移的因素包括括:商品用毒素的的异同点单一毒素和复复合毒素的使使用昆虫种群的抗抗性水平11Cross-resistance:anexample(抗性转移:举举例说明)BindingsitediagramforEuropeancornborer(欧洲玉米螟结结合位点简图图)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避难所AnyhostplantthatdoesnotproduceBttoxinandhasnotbeentreatedwithconventionalBtformulations(maybetreatedwithnon-Btinsecticide)任何不产生Bt毒素并且也未未经常规Bt杀虫剂处理过过的宿主植物物(可能经非非Bt杀虫剂处理过过)Enablesmatingbetweenresistantandsusceptibleadults,resultinginproductionofsusceptibleoffspring抗性和敏感性性成熟植株杂杂交可以产生生敏感性的后后代13Refugeoptions避难所的选择择Structuredrefuge=specifiedsize,locationinrelationtoBtfield,andcrop/plantcompositionCommunity-basedrefuge=neighboringgrowersestablishsharedstructuredrefugeUnstructuredornaturalrefuge=useofalternativehostplants/cropsinplaceofdefinedrefuge结构避难所=特定大小,并且位置和和Bt植物种植区有有一定关系的的区域,此区区域既有农作作物,又有植植被以社区为基础础的避难所=相邻的种植植者建立的一一种共享的结结构避难所非结构或称天天然避难所=用一种寄主主植物和作物物互相交替种种植的模式来来代替人为限限定的避难所所模式14Refugeoptions避难所的选择择Seedbagmix=BtseedbagscontainBtseedandnon-Btseed(e.g.,80%Bt,20%non-Bt);seedmaybebaggedseparatelyormixedtogetherRegionallimit=national/regionalgovernmentenforcedlimitonBtseedsales(e.g.,80%indefinedregion)混装种袋=在在这种含Bt种子的袋子中中既含有Bt种子,也含有有非Bt种子(例如:80%Bt种子,20%非Bt种子),种种子可以先按按小袋分装好好再混和,也也可以直接混混在一起.区域限限制=国家家或地地方政政府对对Bt种子的的买卖卖进行行严格格限制制(例例如:在在一定定区域域内，，只允允许80%的Bt种子的的买卖卖)15SeedmixBlockIn-fieldstrips田地内内的条条带模模式Internalblock(s)内部种种植模模式Border(block)周边种种植模模式Structuredrefugeoptions结构避避难所所的选选择Externalblock外部种种植模模式种子混混和16Otherrefugeoptions其他避避难所所选择择Communityrefuge社区避避难所所模式式80%Btseedcorn玉米种种子20%non-Btseedcorn玉米种种子Naturalrefuge天然避避难所所BtcottonBt棉花w/TBWSoybean大豆Tobacco烟草Tobaccobudworm,烟草蚜蚜虫Heliothisvirescens17Btcornrefugespecifications:anexampleBt玉米米避避难难所所规规范范示示例例20%refugerequiredincornbelt;50%refugerequiredincorn/cottonregionStructuredrefugeisrequired.Refugesmaybeplantedinoneofthefollowingdesigns:In-fieldstrips(4-6rows)Blocks(internalorexternal)Refugerequirementsarethesameforlepidopteranandcoleopteranactiveproducts在Bt玉米米田田中中20%为为避难难所所,在在玉玉米米/棉棉花花田田中中则则为为50%结构构性性避难难所所是必必须须的的.避难难所所可以以按按如如下下的的设设计计来来耕耕作作:田地地内内条条带带(4-6行行)内部部或或外外部部田田块块18Modeling模拟拟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预预测测抗抗药药可可能能性性,评评价价IRM策略略持持久久性性和和帮帮助助调调整整数数据据需需求求的的一一种种有有效效方方法法.模模型型包包括括以以下下组组成成成成分分:生物信息息(害虫虫生物学学,种群群动态)遗传学(R-等位基因因显性/频率,抗性性转移)运行情况况(剂量量,单一一的/叠叠加的毒毒剂,避避难所)19Resistancemonitoring抗性监测测CanhelptoprolongtheefficacyofaninsectresistantcropDesignedtodetectresistance2-3yearsbeforefieldfailureTargetpestsamplingconsistsof:Growerreportsofunexpectedpestdamageininsect-protectedcropfieldsRandompopulationsampling:SamplingbasedonpestprevalenceinregionSamplingtarget:numberofinsectsneededtodetermineresistanceatp<0.01可以延长长抗虫作作物的功功效可以在失失效前监监测抗性性2-3年目标害虫虫取样包包括:种植者在在抗虫作作物区域域内由害害虫造成成的意外外损失报报告随机种群群取样:害虫流行行区域取取样取样目标标:用来来确定抗抗性所需需的害虫虫数量(p<0.01)20Resistancemonitoring(cont.)抗性监测测(续)Bioassaysareusedtodetectpotentialresistanceinsampledpopulations.Assaysinclude:Pestsusceptibility(LC50)DiscriminatingDose(LC99)F2screenConfirmationstudiesareusedtoverifyresistance.Questionsinclude:Istherefieldfailure?Istheinsectresistancetraitexpressed?Isinsectresistancetraitinherited?用生物鉴鉴定来检检测样品品种群中中的潜在在抗性.生物物鉴定包包括:害虫敏感感性鉴定定(LC50)差异剂量量(LC99)F2筛选确认研究究用来核核实抗性性.包括括:区域失效效了么?抗性特征征表达了了么?抗性性可可遗传么么?21Resistancemonitoring:positivehitsforBtcornintheUS?抗性监监测:美美国Bt玉米正正采样样数In2001,mortalityforoneEuropeancornborer(ECB)population(Kandiyohi,MN)was<99%inCry1AbdiscriminatingdoseassayFollow-uptestswithBtplantmaterialrevealedthatpopulationwasnotfieldresistantNofieldresistanceconfirmedforanymonitoredBtcornpest2001年在Cry1Ab不同剂剂量分分析中中,欧欧洲洲玉米米螟种种群的的死亡亡率小小于99%Bt作物的的后续续测试试表明明种群群并没没有田田间抗抗药性性被监测测的Bt玉米害害虫没没有被被证实实产生生田间间抗药药性22Remedialactionplan矫正措措施Ifresistanceisconfirmedthroughresistancemonitoring,aremedialactionplanisimplementedtocontainorslowthespreadofresistantpestpopulations如果抗抗性监监测确确认了了抗药药性,矫矫正措措施可可以减减缓害害虫种种群抗抗药性性的传传播23Remedialactionplan:anexample矫正措措施举举例EPA’splanincludes:MandatoryreportingofsuspectedresistanceUseofalternatecontrolmeasuresinaffectedareasIncreasedresistancemonitoringSuspensionofBtcropsalesinaffectedareasInvestigationofcauseofresistance美国环环保局局措施施包括括:强制要要求对对有怀怀疑的的抗药药性表表现上上报在有影影响区区域使使用其其他管管理措措施增强抗抗性监监测在被影影响区区域终终止Bt玉米销销售对抗药药性原原因进进行调调查24Complianceassurance确保规规范性性CompliancemeasuresimplementedtoensurethatgrowerscomplywithapprovedIRMprogram规范操操作可可以确确保种种植者者按照照害虫虫抗药药性管管理规规则执执行耕耕种操操作.25Complianceassurance:anexample确保规规范性性举例例EPArequiresregistrantstoimplementthefollowingmeasures:ContractsaffirminggroweragreementtocomplywithapprovedIRMstrategy3rdpartygrowersurveysofIRMimplementationOn-farmfieldvisitstoverifyIRMimplementationTipsandcomplaintsonnon-compliersSuspensionofseedaccessfornon-compliers美国环环保局局规定定登记记者必必须实实施以以下方方法:合同规规定种种植者者必须须遵守守IRM策略第三方方对IRM执行情情况进进行调调查田间观观察以以确定定IRM的执行行情况况揭发和和投诉诉不遵遵守规规则的的种植植者对不遵遵守规规则的的种植植者终终止种种子供供应26Growereducation种植者者教育育EducationabouttheneedforIRM,howtoimplementrequirements,andgrowerresponsibilityincomplyingwithIRMrequirements对IRM策略的必要要性,怎怎样完成要要求,和和种植者对对完成IRM要求所担负负的责任进进行教育27SummaryofEPA’sIRMrequirementsforlepidopteran-activeBtcorn美国环保局局对鳞翅目目昆虫敏感感的Bt玉米IRM要求概述20%refugeincornbelt;50%refugeincottonbeltStructuredrefugerequired.Refugesplantedinoneofthefollowingdesigns:in-fieldstrips(4-6rows)blocks(internalorexternal)Industry-widecollaborationoncompliancesurveys在玉米种植植带中20%为避难难所;在在棉花种植植带中为50%结构性避难难所是必需需的.避难难所种植需需为如下设设计中的一一种:田间条带(4-6行行)田块(内部部或外部)广泛合作开开展规范性性调查28SummaryofEPA’sIRMrequirementsforlepidopteran-activeBtcorn(cont.)对鳞翅目昆昆虫敏感的的Bt玉米IRM要求概述(续)Industry-wideuniformityof:GroweragreementsGrowertrainingImplementationoftipsandcomplaints以下行为保保持高度一一致性:种植者协议议种植者培训训监测和投诉诉的实施29SummaryofEPA’sIRMrequirementsforlepidopteran-activeBtcorn(cont.)对鳞翅目昆昆虫敏感的的Bt玉米IRM要求概述(续)Annualreportingrequirements:－Complianceassurance(e.g.,surveys,growercontracts)－Changestogrowereducation－Resistancemonitoringdata－Salesdata年度报告需需要:规范性确认认材料(例例如调查,种植者合合同)种植者教育育的变化抗性监测数数据销售数据30DatasourcesforEPA’’sIRMprogram美国环保局局IRM项目的数据据来源PublishedscientificliteratureIndustrysubmissionsExperts(academia,government,industry)Meetings(advisorypanels,workshops,ESA,NC205,NC46)Fieldvisits已出出版版的的科科学学文文献献工业业企企业业的的报报告告专家家(学学术术界界,政政府府,工工业业界界)会议议(顾顾问问团团,研研讨讨会会,ESA,NC205,NC46)田间间观观察察31KeystosuccessatEPA美国国环环保保局局(EPA)取得得成成功功的的关关键键EPAisresponsivetonewscientificinformationEPAseeksscientificinputfromstateandfederalagencies,academicexperts,andpublicinterestgroupsEPA对最最新新的的科科技技信信息息反反应应积积极极EPA从各各州州和和联联邦邦的的政政府府部部门门,学学术术专专家家和和公公众众团团体体中中寻寻求求科科技技力力量量32KeystosuccessatEPA美国国环环保保局局(EPA)取得得成成功功的的关关键键Conditional(time-limited)registrationsenableEPAtoadaptIRMrequirementsovertimeEPAnegotiatesregulatorychangeswithregistrantsandgrowerorganizations有时时间间限限制制的的注注册册可可以以使使EPA适应应IRM随着着时时间间变变化化而而产产生生的的新新要要求求EPA经常常与