害虫对Bt杀虫蛋白抗性相关受体蛋白互作网络分析

为对Bt杀虫蛋白与化学杀虫剂的协同使用提供理论指导,通过蛋白互作分析方法,以黑腹果蝇Drosophila melanogaster为模型,对化学杀虫剂与Bt杀虫剂作用受体以及抗性相关蛋白的互作网络进行研究。结果表明,Bt杀虫蛋白的27个受体在黑腹果蝇中共存在50个互作蛋白,其中有39个蛋白只与Bt杀虫蛋白抗性相关,11个蛋白还与化学杀虫剂抗性相关,这2类杀虫剂抗性互作网络交集较小,并且重叠蛋白的变异引起交互抗性的概率不大。表明Bt杀虫蛋白与化学杀虫剂产生交互抗性的概率较小,可以将Bt杀虫剂与化学杀虫剂协同使用,提高害虫防治效果,并有效克服或延缓害虫抗性产生。     

Field‐evolved resistance to Bt maize in sugarcane borer (Diatraea saccharalis) in Argentina

BACKGROUND

Maize technologies expressing Bacillus thuringiensis (Bt) insecticidal proteins are widely used in Argentina to control sugarcane borer (Diatraea saccharalis Fabricius). Unexpected D. saccharalis damage was observed to Bt maize events TC1507 (expressing Cry1F) and MON 89034 × MON 88017 (expressing Cry1A.105 and Cry2Ab2) in an isolated area of San Luis Province. Diatraea saccharalis larvae were sampled from MON 89034 × MON 88017 fields in the area to generate a resistant strain (RR), which was subsequently characterized in plant and diet bioassays.

RESULTS

Survivorship of the RR strain was high on TC1507 leaf tissue, intermediate on MON 89034 × MON 88017, and low on MON 810 (expressing Cry1Ab). The RR strain had high resistance to Cry1A.105 (186.74‐fold) and no resistance to Cry2Ab2 in diet bioassays. These results indicate resistance to Cry1F and Cry1A.105 (and likely cross‐resistance between them) but not to Cry1Ab or Cry2Ab2. Resistance to MON 89034 × MON 88017 was functionally recessive. Reviews of grower records suggest that resistance initially evolved to Cry1F, conferring cross‐resistance to Cry1A.105, with low refuge compliance as the primary cause. A mitigation plan was implemented in San Luis that included technology rotation, field monitoring, and grower education on best management practices (BMPs) including refuges.

CONCLUSION

In the affected area, the resistance to Cry1F and Cry1A.105 is being managed effectively through use of MON 89034 × MON 88017 and MON 810 in combination with BMPs, and no spread of resistance to other regions has been observed. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

转sck/cry1Ac基因稻谷对米蛾幼虫解毒酶系的影响

采用酶活力测定及酯酶同工酶电泳方法研究米蛾(Corcyra cephalonica)幼虫取食表达SCK/Cry1Ac毒蛋白的转基因稻谷后体内重要解毒酶活力的变化,明确其代谢毒蛋白的主要酶类。结果表明:取食转Bt基因稻谷米蛾幼虫体内的α-乙酸萘酯酶、碱性磷酸酯酶的活力在24～72h显著低于对照;酸性磷酸酯酶活力在12、48h和72h时也显著低于对照;而α-乙酸萘酯羧酸酯酶和乙酰胆碱酯酶的活力显著高于对照。谷胱甘肽-S-转移酶的活性除饲喂24h的处理外,其他处理与对照无显著差异。此外处理72h后米蛾幼虫体内酯酶同工酶谱有4条酯酶酶带,4种酯酶Est1、Est2、Est3、Est4的活性均受到不同程度的抑制,酯酶Est4的抑制效果最明显。这些解毒酶和酯酶同工酶直接参与Bt毒蛋白的代谢作用。     

味精废水驯化后苏云金杆菌菌株晶体和芽孢的组分及特性

对苏云金杆菌出发菌株H3a经长期味精废水驯化获得的8种变异菌株进行了茄子瓶装味精废水培养基培养,并应用液体双相法分离了晶体和芽孢。通过SDS-PAGE电泳确定了晶体蛋白组分的分子量为120、104、67—68、43—45kD,芽孢蛋白组分的分子量为148、120、67—68、55、46、24、16kD,二者共同的蛋白分子量为120、68及43—46kD;选取经分离后的G．1菌株晶体并通过DEAE—离子交换纤维素柱层析和Sephadex G-100凝胶柱层析分离,得到了两个主峰,分子量为120、68kD。生物测定120、68kD肽段对小菜蛾的毒性,结果其半致死浓度分别为0．609、＞25μg/ml,而全培养液为6．03mg/ml。     

Cross-resistance between a Bacillus thuringiensis Cry toxin and non-Bt insecticides in the diamondback moth

BACKGROUND: Bacillus thuringiensis Berliner (Bt) crystal (Cry) toxins are expressed in various transgenic crops and are also used as sprays in integrated pest management and organic agricultural systems. The diamondback moth (Plutella xylostella L.) is a major worldwide pest of crucifer crops and one that has readily acquired field resistance to a broad range of insecticides.RESULTS: Selection of a subpopulation of the P. xylostella SERD4 population with the pyrethroid deltamethrin increased resistance to both deltamethrin and Cry1Ac relative to an unselected subpopulation. Selection of a second subpopulation with the Bt toxin Cry1Ac also increased resistance to both Cry1Ac and deltamethrin. A complementation test between the Cry1Ac-selected and deltamethrin-selected subpopulations suggested the presence of a common genetic locus or loci that control resistance to both insecticides. A piperonyl butoxide analogue with potent inhibitory activity against insect esterases significantly increased the toxicity of Cry1Ac and deltamethrin against the respective resistant subpopulations, but showed no such synergism with the unselected subpopulation of SERD4.CONCLUSION: Selection of one resistance phenotype resulted in the simultaneous selection of the other. This phenomenon could be due to a single mechanism acting against both classes of insecticide or to genetically linked, but separate, mechanisms.     

水稻胡麻斑类似病危害转Bt稻“克螟稻”初报

 于田间转Bt稻“克螟稻”稻叶上观测到一种病斑，病斑中心和周围均呈褐色，长椭圆形与稻胡麻斑病类似，平板上分离到的病原菌菌丝呈灰褐色，菌丝有多个隔膜，分生孢子梗成丛，但在PDA培养基上，产生的分生孢子特征与稻胡麻斑病不吻合。从为害级别和严重度上分析克螟稻对胡麻斑类似病的感病程度远远超过其亲本秀水11。克螟稻叶片间发病速率增长迅速，而秀水11叶片间发病速率增长缓慢。     

转Bt基因棉花对土壤微生物的影响

在大田和盆栽条件下，以转Bt基因抗虫棉晋棉26号和其具有相似遗传背景的普通棉花品种晋棉7号为材料，研究棉花不同生育期的土壤细菌、真菌、放线菌及其生理菌种的变化。结果表明，转Bt基因棉晋棉对土壤微生物种类和数量有一定的影响，在某些生育期显著高于或低于普通非转基因棉花，或者差异不显著。因此，转基因安全评价需要对土壤微生物进行评价。     

Effects of Transgenic Bt+CpTI Cotton on Field Abundance of Non-Target Pests and Predators in Xinjiang,China

Transgenic insect-resistant cotton is being increasingly planted in Xinjiang cotton-planting regions, where geographical climate conditions and species composition of pests and natural enemies are greatly unique in China. Limited studies have been conducted on the ecological impacts of transgenic insect-resistant cotton, especially for transgenic double genes (Bt+CpTI) cotton, in this region. In this study, the potential effects of transgenic Bt+CpTI cotton on the seasonal abundance of non-target pests and predators were assessed from 2009 to 2011 in Korla, Xinjiang. The results showed that species composition and seasonal abundance of 5 groups of pests and 5 groups of predators were not significantly different between transgenic Bt+CpTI cotton and non-transgenic cotton every year. It suggests that transgenic Bt+CpTI cotton per se does not affect the population dynamics of non-target pests and predators on this crop in Xinjiang.     

Population dynamics and biological control of European grapevine moth (Lobesia botrana: Lepidoptera: Tortricidae) in Albania using different strains of Bacillus thuringiensis

This work describes the results of an experiment conducted in a vineyard in Durres, Albania from 2004 to 2006, to study the efficacy of two strains of Bacillus thuringiensis Berliner, vars kurstaki and aizawai, against the moth Lobesia botrana Denis & Schiffermüleler (Lepidoptera: Tortricidae), a major pest of grapevines. The experimental results revealed that the two strains were significantly more effective than the control, with var. aizawai being more effective than var. kurstaki. Bacillus thuringiensis (Bt) provided better protection of the bunches from the second generation compared to the third one showing the short persistence of action of the active ingredient. The high degree of efficacy supported a role for Bt in grapevine moth management. Our study also provided insights into the population dynamics of the European grapevine moth under Albanian climatic conditions. Despite the necessity for the pheromone traps to indicate the start of the flight period, the experiments confirmed the lack of a correlation between the population dynamics and the level of damage by the pest. Pheromone trapping can offer very useful indications regarding the start of the flight period of each generation and its duration but not on the severity and incidence of the pest.     

The Research of Bt and OC Gene Cotransformation in Tobacco Chloroplast

The Bt Cry IA (C) chloroplast expression cassette and OC chloroplast expression cassette were constructed. The Bt expression cassette contained the 3.5 kb wild type Bt Cry IA (C) gene under the control of the strong light-induced psbA promoter and terminator from rice (Oryza sativa. L) chloroplast, the gene:trnH-psbA-trnk from tobacco (Nicotiana tabacum. L) as the homologous fragment. The OC chloroplast expression cassette contained the OC gene under the control of 16S promoter and terminator from tobacco, the tobacco gene: psbA-ORF512 as homologous fragment. The two cassettes both had the aadA gene expression cassette as the selectable marker. Leaves of tobacco were cotransformed with the particle bombardment method. After selection by spectinomycin, the transformants were obtained. The integration of Bt and OC gene were confirmed by Southern-blotting analysis, and Western-blotting analysis. Proteinase inhibitor assays showed that the Bt and OC gene had expressed. Bioassays showed that the transgenic tobacco had a significant resistance to the larvae of cotton bollworm ( helicoverpa zea ).