棉铃虫幼虫对转Bt基因棉的行为学反应研究

转Bt基因棉花的育成及应用将对棉花害虫特别是棉铃虫的防治产生深刻的影响。本文初步探讨了棉铃虫幼虫对转Bt基因棉的行为学反应,旨在为组建以转Bt基因棉为基础的棉虫综合治理体系提供理论指导。 1 材料与方法 1.1 供试材料供试转Bt基因棉品系(代号R93-4)及其亲本对照(中棉所12)均由中国农科院棉花所提供。供试棉铃虫幼虫为前一年秋季田间采老熟幼虫室内化蛹越冬、室内饲养所得。     

转CpTI+Bt基因棉和转Bt基因棉对甜菜夜蛾种群增长和行为的影响

利用室内饲喂法,以泗棉3号为对照,研究转双价(Bt CpTI)基因棉SGK321和转单价(Bt)基因杂交棉科棉3号对甜菜夜蛾室内种群生长发育和趋性的影响。结果表明:SGK321、科棉3号饲喂的甜菜夜蛾幼虫死亡率、成蛹下降率和幼虫成蛾下降率显著高于对照,且SGK321饲喂的化蛹下降率显著高于科棉3号。SGK321、科棉3号饲喂的甜菜夜蛾幼虫期显著长于泗棉3号,其蛹重显著轻于泗棉3号;SGK321饲喂的幼虫期长于科棉3号,其蛹期和蛹重接近于科棉3号;三种棉花饲喂的甜菜夜蛾的产卵前期、产卵期、产卵量均表现为SGK321<科棉3号<泗棉3号,其中SGK321饲喂的产卵期显著短于泗棉3号;SGK321、科棉3号饲喂的雌成虫寿命相近,但明显短于泗棉3号。三种棉花饲喂的甜菜夜蛾净增长率(R0)、内禀增长率(rm)、周限增长率(λ)和种群增长指数(I)均表现为SGK321<科棉3号<泗棉3号;世代平均周期(T)和种群加倍时间(DT)均表现为SGK321>科棉3号>泗棉3号。甜菜夜蛾2～5龄幼虫对棉花的趋性强弱顺序为泗棉3号>科棉3号>SGK321。     

转Bt基因植物对不同抗性棉铃虫的生长抑制作用

采用转Bt基因的烟草和棉花 ,对经转Bt单基因、转Bt与CpTI双基因烟草汰选 1 8代和常规烟草处理的棉铃虫种群进行生长抑制作用的比较测定。结果表明 ,转Bt烟草对以汰选后的抗Bt单基因汰选棉铃虫种群的体重抑制作用显著低于转双基因烟草汰选种群和对照种群 ;转Bt棉花对单基因种群的杀虫活性、体重、龄期发育以及化蛹率的抑制作用亦显著低于双基因种群和对照种群     

抗Bt棉铃虫种群的交互抗性研究

分别用对CyrlAc抗性达11．6倍的Bt棉叶和Bt粉剂（Btk)汰选棉铃虫（Heliocoverpa armigera)种群（对Btk的抗性指数为5．2倍）,测定了其对不同Bt制剂,Bt毒素,化学农药的交互抗性,结果表明：停止汰选后,Bt棉叶汰选种群对CrylAc的抗性指数为5．9倍,对CrylAc 1C的交互抗性为3．7倍,对Btk的敏感性降低,对Bta,Cry2A无交互抗性,Btk汰选种群对Btk的抗性指数为4．1倍,对Bta,CrylAc,CrylAc 1C的交互抗性为2．3,3．1,2．3倍,对Cry2A无交互抗性,两汰选种群对化学农药灭多威,辛硫磷,氯氰菊酯的敏感性均有所增加。     

转Bt 基因抗虫玉米对棉铃虫杀虫活性的初步评价

国内外在转 Bt基因抗虫作物的研究和应用上已取得重大进展 ,其中 Bt抗虫棉已在美国、澳大利亚、中国等进入商品化应用阶段 ,近年来种植面积增长很快 ,并取得了显著的经济、生态和社会效益。 1 997年下半年 ,我国农业部分别批准了孟山都公司申报的保铃棉○R在河北省商业化生产和 Bt玉米在我国多省份的田间种植。其中保铃棉 ○R已由河北省定名为新棉 33B,1 998年在全省实际种植了近 1 0万 hm2 ,1 999年的种植面积已达 1 5万 hm2 。我国自主研制的 Bt抗虫棉也于 1 998年开始商品化应用 ,当年种植面积即达 1 0万 hm2以上 ,1 999年推广总面积…     

新疆南部棉区转Bt基因棉花对棉铃虫抗性的季节性变化规律

采用ELISA检测和室内生物测定方法,测定6个转Bt基因棉花品种(系)不同生育期叶片中的Bt毒蛋白含量及其对各世代棉铃虫的抗性水平。转Bt基因棉花叶片中的Bt毒蛋白含量总体上随着棉花生育期的推进而逐渐下降,6个品种(系)叶片的Bt毒蛋白含量子叶期最高,达1 210.03～1 733.15 ng/g,与子叶期相比,三叶期、七叶期、盛蕾期、花铃期、吐絮期Bt毒蛋白含量减少幅度为2.5%～96.0%。6个品种(系)对第4代棉铃虫幼虫抗虫性较低,毒杀效果仅为19.0%～41.3%。幼虫的校正死亡率逐代下降,各棉花品种对第4代幼虫的校正死亡率仅为12.0%～36.2%。     

部分GK系列Bt棉对棉铃虫抗性的田间评价

１９９７～１９９８年在河北省廊坊市和１９９８年在河南省新乡市分别研究了转ＣｒｙＩＡ Ｂｔ抗虫基因棉花ＧＫ－２、ＧＫ－５和ＧＫ－１２对棉铃虫的抗性水平。研究结果表明,ＧＫ－２和ＧＫ－１２在整个生育对棉铃虫皆保持极高的抗性,在对照普通棉花品种棉铃虫高峰期百株幼虫２代４４～１３８头,３代１１３～１３８头和４代１４４头密度下,对棉铃虫的控制效果分别达８８．７１％～９５．４５％、９２．７５％～９７．６５％和     

转Bt基因玉米对棉铃虫的抗性评价

棉铃虫Helicoverpa armigem（Htlbner）是常年危害玉米的重要害虫。转Bt基因抗虫玉米为害虫的防治提供了新的途径。采用室内离体生物测定方法测定了孟山都转Bt基因抗虫玉米Yield—Gard不同组织对棉铃虫初孵幼虫的杀虫活性以及田间人工接虫抗性鉴定。Bt玉米花丝、苞叶和幼嫩雌穗对棉铃虫具有较高的杀虫活性，取食Bt玉米花丝和幼嫩雌穗（籽粒和穗轴）的棉铃虫初孵幼虫不能存活和完成幼虫期发育，而对照分别有51．0％和22．0％个体完成幼虫期发育。以Bt玉米雌穗苞叶饲养棉铃虫初孵幼虫，5天后幼虫全部死亡，而非Bt玉米对照仅为16．0％，差异显著。田间花丝期人工接种棉铃虫抗性鉴定试验结果表明，Bt玉米雌穗被害率为3．5％，危害级别为0．007，百株存活幼虫14．3头。而非Bt玉米雌穗被害率达到82．5％，危害级别为2．51，平均百株存活幼虫79．6头，显著高于Bt玉米。这些结果说明转Bt基因玉米穗期对棉铃虫的防治效果明理．     

转Bt基因棉生态风险的研究进展

从转Bt基因棉对棉田天敌、非靶标害虫的影响、抗虫的持久性、毒蛋白表达的时空性等方面综述了转Bt基因棉生态风险的研究进展。     

新疆棉区转Bt基因棉对棉田主要害虫及其天敌种群数量的影响

20 0 0～ 2 0 0 1年 ,在新疆棉区系统地研究了转Bt基因棉田主要害虫及其天敌的发生规律。结果表明 :转Bt基因棉对棉铃虫有良好的控制作用 ,发生高峰期百株落卵量和百株幼虫数量都显著低于常规对照 ,转Bt自控田和转Bt化防田棉蚜和棉盲蝽发生数量则显著高于常规棉对照田。在天敌方面 ,转Bt自控田和转Bt化防田较常规棉对照田 ,丽草蛉种群数量有所增加 ,而小花蝽和黑食蚜盲蝽等 5种捕食性和几种寄生性天敌数量都有所下降。转Bt基因棉田棉蚜和棉盲蝽等刺吸性害虫发生数量加重而多种天敌数量减少的趋势值得引起重视。鉴于新疆地区棉铃虫发生数量较低目前无需专门防治的特点 ,作者建议 :可以考虑推广农艺性状较好的常规棉品种并保护天敌 ,以达到控制害虫、丰产丰收的目的。     

Regional reversion of insecticide resistance in Helicoverpa armigera (Lepidoptera: Noctuidae) is associated with the use of Bt cotton in northern China

A continuous programme for monitoring resistance of Helicoverpa armigera (Hubner) to commonly used insecticides was undertaken for assessing the impact of Bt cotton planting on the evolution of the pest resistance from 1994 to 2002 in China. The bioassay results showed that the resistance levels per year in field populations of H armigera to lambda-cyhalothrin, phoxim and endosulfan decreased, respectively, to 9-15-fold, 11-14-fold and 6-8-fold in 2001-2002 from 197-262-fold, 52-74-fold and 18-38-fold before the cultivation of Bt cotton in 1997. This significant increase in susceptibility to insecticides is expected to result in a reduction in insecticide application for H armigera control in Bt cotton. It is concluded that Bt cotton is playing an important role in the long-term management of H armigera by increasing the potential for natural and chemical control of the pest.     

Toxicity of Mixtures of Bacillus thuringiensis with Endosulfan and Other Insecticides to the Cotton Boll Worm Helicoverpa armigera

In the laboratory, low concentrations of Bacillus thuringiensis Berliner (B.t.), as ‘Dipel’ 2X applied (at about the LC₅) to cotton leaves enhanced the activity of endosulfan and reduced resistance to endosulfan from approximately seven fold to two fold in neonate larvae of Helicoverpa armigera (Hubner). Low (LC₅) concentrations of endosulfan also increased the toxicity of B.t. Both endo-sulfan and B.t. increased the toxicity of the stomach poison cryolite to H. armigera. This increased toxicity was not observed where B.t./endosulfan combinations were applied topically to larvae or where B.t. was combined with organophosphorus or pyrethroid insecticides which are considered primarily to be contact toxicants. Mixtures of B.t. and endosulfan applied at equitoxic concentrations were less toxic than similar concentrations applied alone.     

棉铃虫围食膜中Bt抗性相关蛋白的分离与鉴定

棉铃虫是世界性的重要农业害虫。围食膜作为昆虫抵御病原微生物入侵及有害物质的第一道天然保护性屏障,其上可能存在与Bt抗性相关的受体蛋白。本研究以Bt Cry1Ac抗性和敏感品系的棉铃虫围食膜为对象,采用NuPAGE电泳技术、配体杂交、质谱鉴定和生物信息学分析等技术,测定了围食膜蛋白含量,鉴定了蛋白质的组成及与Bt Cry1Ac毒素的结合能力。结果表明敏感品系围食膜中蛋白含量为22.19%,抗性品系围食膜中蛋白含量为26.99%。抗、感品系棉铃虫围食膜上存在与Cry1Ac毒素结合的6个差异蛋白,推测其中棉铃虫羧酸酯酶蛋白和血影蛋白是2个有意义的抗性相关蛋白,2个新蛋白可能参与Bt抗性。研究证明棉铃虫围食膜上存在Bt结合蛋白且与抗性相关,为进一步明确Bt抗性机制、制定合理的Bt抗性治理策略提供了理论依据。     

A perspective on management of Helicoverpa armigera: transgenic Bt cotton,IPM, and landscapes

Helicoverpa armigera is a major pest of agriculture, horticulture and floriculture throughout the Old World and recently invaded parts of the New World. We overview of the evolution in thinking about the application of area‐wide approaches to assist with its control by the Australian Cotton Industry to highlight important lessons and future challenges to achieving the same in the New World. An over‐reliance of broad‐spectrum insecticides led to Helicoverpa spp. in Australian cotton rapidly became resistant to DDT, synthetic pyrethroids, organophosphates, carbamates and endosulfan. Voluntary strategies were developed to slow the development of insecticide resistance, which included rotating chemistries and basing spray decisions on thresholds. Despite adoption of these practices, insecticide resistance continued to develop until the introduction of genetically modified cotton provided a platform for augmenting Integrated Pest Management in the Australian cotton industry. Compliance with mandatory resistance management plans for Bt cotton necessitated a shift from pest control at the level of individual fields or farms towards a coordinated area‐wide landscape approach. Our take‐home message for control of H. armigera is that resistance management is essential in genetically modified crops and must be season long and area‐wide to be effective. © 2016 Society of Chemical Industry     

Seasonal Dynamics of Metabolic Mechanisms Mediating Pyrethroid Resistance in Helicoverpa armigera in Central India

Very high cypermethrin and fenvalerate resistance frequencies were recorded in Helicoverpa armigera (Hübner) populations in central India during the 1993–94, 1994–95 and 1995–96 cropping seasons. Synergism assays and biochemical analyses of detoxification enzyme levels indicated that mono-oxygenases and esterases were important metabolic mechanisms mediating pyrethroid resistance. Piperonyl butoxide- (PBO) and profenofos-suppressible pyrethroid resistance were correlated with enhanced levels of cytochrome P450 and general esterases respectively. Enzyme assay data indicated that high cytochrome P450 levels generally coincided with low esterase activity and vice versa. Similarly, synergist bioassays showed that PBO-insensitive resistance was frequently associated with profenofos-sensitive resistance and vice versa. Oxidase- and esterase-mediated mechanisms evidently alternated in a reciprocal manner, with perceptible shifts in relative importance occurring during mid-October in all three seasons and in late January in 1995. Apart from metabolic mechanisms, a synergist-insensitive resistance mechanism (believed to be nerve insensitivity), accounted for an average of 51, 30 and 28% of cypermethrin resistance during the 1993–94, 1994–95 and 1995–96 seasons respectively. © 1997 SCI.     

Selection and heritability of resistance to Bacillus thuringiensis subsp kurstaki and transgenic cotton in Helicoverpa armigera (Lepidoptera: Noctuidae)

Compared with an unselected susceptible population, a cotton bollworm, Helicoverpa armigera (Hübner), population selected for 22 generations with transgenic cotton leaves (modified Cry1A) in the laboratory developed 11.0-fold resistance to Cry1Ac (one single-protein product MVPII). Resistance to Bacillus thuringiensis Berliner subsp kurstaki (Btk) was selected for 22 generations with a 5.2-fold increase in LC50. The estimated realized heritabilities (h2) of resistance for transgenic-cotton- and Btk-selected populations were 0.1008 and 0.2341, respectively. This reflects the higher phenotypic variation in response to Cry1Ac in the transgenic-cotton-selected population. This variation may have been caused by differences in protein toxin levels expressed in different growth stages of the transgenic cotton. Because of the different slopes of the probit regression lines between Cry1Ac and Btk, the estimated realized h2 cannot be used visually to compare resistance development to Cry1Ac and Btk in H armigera. Thus, the response quotient (Q) of resistance was also estimated. The Q values of resistance for transgenic-cotton- and Btk-selected populations were 0.0763 and 0.0836, respectively. This showed that the rate of resistance development would be similar in both selection populations. This result indicates that the selection of resistance using transgenic cotton is different from that selected using the single toxin. Resistance risk to transgenic cotton and Btk in field populations was assessed assuming different pressures of selection by using the estimated h2. Assuming the h2 of resistance in a field population was half of the estimated h2, and the population received prolonged and uniform exposure to transgenic cotton or Btk causing >70% mortality in each generation, we predicted that resistance would increase 10-fold after <23 generations for Cry1Ac in transgenic cotton-selected-populations and after <21 generations for Btk in Btk-selected populations. Cross-resistance would be expected after <48 generations for Btk in transgenic-cotton-selected populations and after <21 generations for Cry1Ac in Btk-selected population. The results show that the potential to evolve resistance is similar in both transgenic-cotton- and Btk-selected populations, but that cross-resistance development to Btk is slower in transgenic-cotton-selected populations than cross-resistance development to Cry1Ac in Btk-selected populations.     

Bt抗性和敏感棉铃虫钙黏蛋白及氨肽酶N1表达量的比较

棉铃虫体内的钙黏蛋白（CAD）和氨肽酶N1（APN1）是Bt的主要作用靶标,两种受体蛋白的变化也是棉铃虫对Bt产生抗性的主要原因。本文利用实时荧光定量PCR技术比较了Bt抗性和敏感棉铃虫CAD和APN1的表达量变化,分析受体蛋白表达量变化与抗性的关系。结果表明,与敏感品系相比,抗性品系棉铃虫CAD和APN1的表达量明显降低,1、2龄幼虫的差异达到极显著。在敏感品系中,CAD和APN1的表达量随龄期的增加呈现“V”字形变化,1、2龄幼虫的表达量最高,3、4龄时显著降低,到5龄时表达量又有所增加。抗性品系中CAD和APN1的表达量提前降低,与表达量最高的1龄幼虫相比,2、3龄时表达量显著降低,到4、5龄时又略有回升。说明棉铃虫中肠钙黏蛋白、APN1表达量的下降与抗性相关,且不同龄期棉铃虫幼虫表达量不同。     

转B.t.基因棉抗棉铃虫性的鉴定技术及其应用

根据近年对我国培育出的转基因棉抗虫性鉴定实践，总结制定出转基因棉抗虫性鉴定技术和标准。应用该技术鉴定出３６号等转Ｂ．ｔ．基因棉高抗棉铃虫的株系，并已进入田间试种