转Bt基因作物毒素在土壤中降解特性的研究进展

总结了国内外转Bt基因作物在土壤中降解特性的研究结果,讨论了土壤有机、无机组分与毒素蛋白的关系,阐明了转基因毒素蛋白在土壤中的降解与影响因素,揭示了转Bt基因作物在土壤中降解的生态环境效应,并提出了今后应深入研究的问题和方向.     

Effects of Bt transgenic crops on soil ecosystems: a review of a ten-year research in China

Bacillus thuringiensis (Bt) transgenic cotton is the unique Bt transgenic crop planted on a large scale in China, and its commercialized varieties and hectareage had increased rapidly in China during the past decade (1997–2006) with broad geographic distribution for the economic, environmental, and health benefits. In 2004, the planting area of Bt transgenic cotton in China ranked first worldwide with up to 370 × 10⁶ hm². In addition, Bt transgenic rice varieties in field tests have been close to approval for commercialization. However, ecological risks, a complex issue of Bt transgenic crops on soil ecosystem is urgently faced in China due to more than 60 varieties transferred single or bivalent Bt genes grown under diverse geographic regions. Two main pathways, biomass incorporation and root exudates, are involved in the effects of Bt transgenic crops on soil ecosystems. In this paper, the research results in recent years in China involved in the effects of Bt transgenic crops (Bt transgenic cottons and rice) on soil ecosystems were summarized with special attentions paid to the release and persistence of Bt toxins, and the toxicology to microorganisms, as well as the change of soil biochemical properties in soils where Bt transgenic crops were planted or incubated with their biomass. In addition, the complexity and current research defaults of ecological risk evaluation of Bt transgenic crops in China were highlighted.     

Effects of insect-resistant transgenic cotton on ground-dwelling beetle assemblages(Coleoptera)

We compared the ground-dwelling beetle assemblages under four scenarios in which transgenic Bt(Cry 1Ac) cotton(33B),transgenic Bt(Cry 1Ac)+CpTI cotton(SGK321),conventional cotton(33),conventional cotton(Shiyuan 321) in North China.During the survey in two years(2009-2010),24 ground beetle species were captured with pitfall traps in 20 plots which included five replicates for each cotton type.No significant difference was observed in the number of ground beetle species captured,activity density,evenness and Shannon-Wiener diversity among the four cotton varieties.Chlaenius posticalis was less abundant in transgenic Bt+CpTI cotton(SGK321) fields than its conventional cotton(Shiyuan 321),but more abundant in transgenic Bt cotton(33B) fields compared with its conventional cotton(33).There was no significant difference for other abundant species between in transgenic cotton and in conventional cotton fields.Based on non-metric multidimensional scaling(NMDS) analysis,ground-dwelling beetle assemblages were similar in transgenic and conventional cotton over the two years,but the ground-dwelling beetle assemblages in transgenic cotton 33 B significantly differed from that in the conventional cotton(strain 33) in 2010.No strong evidence that the transgenic cotton effect on ground-dwelling beetle assemblages was found in this study.     

转Bt基因作物对土壤酶活性和土壤肥力影响的研究进展

随着转Bt基因作物种植面积的逐年增加,人们对转基因作物释放后潜在的安全性也越来越关注。转Bt基因作物可以通过根系分泌或植株残体的形式将Bt蛋白释放到土壤中,残留的Bt蛋白在富集的过程中有可能对土壤生态环境中的土壤酶活性及土壤肥力等造成影响,但这些影响作用因不同的Bt作物和不同的土壤环境而不尽相同。商业化转Bt基因作物的大规模环境释放对土壤酶活性和土壤肥力的可能影响仍需要在不同生态区开展长期定位检测和评价。本文对转Bt基因作物的发展及其种植和秸秆降解过程中对土壤酶活性和土壤肥力影响的研究进展进行述评,为转Bt基因作物对土壤环境的生态风险评价提供参考。     

转Bt基因作物毒蛋白对根际土壤生态系统影响研究进展

随着商业化转Bt基因作物的大规模种植,研究Bt毒蛋白对土壤生态系统的可能影响,对评价转基因作物的生态风险具有重大意义。文章综述了转Bt基因作物对根际土壤生态系统影响的研究进展,包括毒蛋白在根际土壤中的存活特性,微生物利用与降解,以及毒蛋白对根际土壤微生物区系和酶活性的影响。并对以后的研究提出几点建议。     

转Bt基因作物及其安全性研究

随着转Bt基因作物的推广和应用,Bt作物的安全性问题也越来越受到重视。文章从Bt基因的分类、基因的克隆及应用,以及转Bt基因作物的生态安全性等方面进行了论述。Bt基因可以通过有性杂交,进入非转基因作物栽培种及野生近缘种中,造成基因污染,害虫在多代食用转Bt基因植物后可以产生抗性,而且转Bt基因作物对非靶标昆虫也有一定的影响,转Bt基因作物可以通过根系向土壤中释放Bt毒蛋白,对土壤生态系统产生影响。另外已经发现大豆(EPSPS)中的转基因有向人类肠道微生物转移的现象。本文综述了对Bt基因的利用进展及对环境及生物的影响,希望能为正确认识和研究利用转Bt基因作物提供一些思路。     

害虫对苏云金芽孢杆菌的抗性及其延缓措施

苏云金芽孢杆菌(Bacillusthuringiensis,简称Bt)在害虫防治中发挥着重要作用。现已表明,有近20种昆虫可对Bt生物制剂产生抗性,转Bt基因作物的释放更加剧了害虫的抗性进化。开展害虫的抗性研究,加强对Bt基因的保护,对持续利用Bt生物制剂和转Bt基因作物具有非常重要的意义。     

昆虫Bt作物抗性与中肠类钙粘蛋白的关系

Bt作物已在世界范围内广泛种植,为有效控制害虫的危害发挥了重要作用。靶标害虫的抗性问题是影响Bt作物长期利用的关键因素。通过分析Bt Cry1A毒素的主要受体类钙粘蛋白（cadherin-like）的生物学特性及其与Bt毒素的结合作用,讨论类钙粘蛋白基因突变与Bt抗性的关系,综述了基于基因突变的抗性分子检测技术的研究进展。     

苏云金芽孢杆菌杀虫机理及害虫对其抗性机制的研究进展

苏云金芽孢杆菌(Bacillus thuringiensis,Bt)杀虫晶体蛋白具有高度专一性,其只对靶标害虫有效,对天敌等其他昆虫无害,转Bt基因植物和Bt杀虫剂是目前世界上产量最大、应用最广泛的生物防治技术。通过对Bt的发现和分类、Bt的结构与功能、Bt毒蛋白的杀虫机理、昆虫对Bt的抗性机制及昆虫体内Bt受体蛋白与抗性的关系等研究现状的论述与分析,对Bt作物害虫抗性治理策略和前景进行了展望。     

Ovipositional responses of Spodoptera frugiperda on host plants provide a basis for using Bt-transgenic maize as trap crop in China

Spodoptera frugiperda, the pest fall armyworm(FAW), is widespread in more than 100 countries. To date, planting insectresistant transgenic crops is one of the main control methods in its native countries. In this study we evaluated Bt-transgenic maize(Bt maize) and non-transgenic(conventional) maize and six other host plants in greenhouse pot experiments and field trials for oviposition preference by the Chinese populations of FAW. In laboratory trials, female moths preferred to oviposit on maize with no significant preference between conventional and Bt maize. However, after conventional and transgenic maize were exposed to FAW larvae and damaged, oviposition was significantly higher on transgenic maize than on the conventional one. Field trials showed that for plants less damaged at an early stage(seedling stage), oviposition of FAW on transgenic and conventional maize was significantly higher than that on wheat, sorghum, foxtail millet, peanut and soybean while showing no significant difference between transgenic or conventional maize. FAW adults mainly laid eggs on Bt maize, while the larval density and leaf damage rating or percentage of damaged plants were significantly lower than on conventional maize. Larval density and its damage on conventional maize were significantly higher than that on Bt maize and the other five hosts. Thus, maize is a highly preferred and suitable host for S. frugiperda feeding and ovipositing, and Bt maize can be used as trap crop to protect other crops.     

转基因作物生产应用效果综合分析与评价——以转基因抗虫棉为例

在2002～2003年对河北主产棉区农户调查和相关科研、推广人员访谈的基础上,运用农业科学、经济学和社会学等多学科交叉的方法,从转基因抗虫棉应用的技术、经济、社会等多角度对农户采用该技术的应用效果进行了分析.结果表明:转基因技术的应用效果与农户生产行为、认知等存在交互作用,农户表现出规避风险,追求利润最大化的生产行为,但同时也存在生产管理和投入的盲目性;该技术的应用在一定程度上增加了农户来自农业的经营收入,但由于受多方面因素的影响,其在农户的生计系统呈现复杂的技术形态;政府等相关部门应加强转基因作物种子及生产应用过程的管理,并针对我国农户特有的小农户、小规模、多样性和复杂性等特点采取针对性措施,最终以改善农户生计为目的发展转基因作物.     

Bt毒蛋白在转基因植物中的表达

随着抗虫转基因植物的推广和大面积商业化种植,Bt毒蛋白在转基因植物中的表达引起了人们的重视。综述了玉米、棉花、水稻等抗虫转基因植物的Bt毒蛋白表达及其时空变化规律。     

Yield effects of genetically modified crops in developing countries

Onfarm field trials carried out with Bacillus thuringiensis (Bt) cotton in different states of India show that the technology substantially reduces pest damage and increases yields. The yield gains are much higher than what has been reported for other countries where genetically modified crops were used mostly to replace and enhance chemical pest control. In many developing countries, small-scale farmers especially suffer big pest-related yield losses because of technical and economic constraints. Pest-resistant genetically modified crops can contribute to increased yields and agricultural growth in those situations, as the case of Bt cotton in India demonstrates.     

转Bt基因作物对哺乳动物食品的安全性评估

综述了Bt毒蛋白、转Bt基因作物对哺乳动物安全性评估等内容。     

Suppression of cotton bollworm in multiple crops in China in areas with Bt toxin-containing cotton

Transgenic cotton that has been engineered to produce insecticidal toxins from Bacillus thuringiensis (Bt) and so to resist the pest cotton bollworm (Helicoverpa armigera) has been widely planted in Asia. Analysis of the population dynamics of H. armigera from 1992 to 2007 in China indicated that a marked decrease in regional outbreaks of this pest in multiple crops was associated with the planting of Bt cotton. The study area included six provinces in northern China with an annual total of 3 million hectares of cotton and 22 million hectares of other crops (corn, peanuts, soybeans, and vegetables) grown by more than 10 million resource-poor farmers. Our data suggest that Bt cotton not only controls H. armigera on transgenic cotton designed to resist this pest but also may reduce its presence on other host crops and may decrease the need for insecticide sprays in general.     

转vip3基因作物研究进展

苏云金芽孢杆菌(Bacillus thuringiensis,Bt)杀虫晶体蛋白(Insecticidal Crystal Proteins,ICPs)转基因作物在全球种植已近15年。随着转基因作物种植面积的扩大,害虫对Bt杀虫蛋白产生抗性已成为一个严峻的问题。通过研究发现,苏云金芽孢杆菌的营养生长阶段可产生一种新的毒素,即VIP3蛋白。VIP3蛋白与已知的ICPs没有序列同源性和结构相似性,表达VIP3对十多种鳞翅目害虫具有毒杀作用,具有更广泛的抗虫谱,尤其可毒杀小地老虎(Agrois ipsilon)等对Bt非敏感害虫,对环境生物没有不良影响,是防治抗性害虫及扩大抗虫谱的一种新策略。     

Engineering modified Bt toxins to counter insect resistance

The evolution of insect resistance threatens the effectiveness of Bacillus thuringiensis (Bt) toxins that are widely used in sprays and transgenic crops. Resistance to Bt toxins in some insects is linked with mutations that disrupt a toxin-binding cadherin protein. We show that susceptibility to the Bt toxin Cry1Ab was reduced by cadherin gene silencing with RNA interference in Manduca sexta, confirming cadherin's role in Bt toxicity. Native Cry1A toxins required cadherin to form oligomers, but modified Cry1A toxins lacking one alpha-helix did not. The modified toxins killed cadherin-silenced M. sexta and Bt-resistant Pectinophora gossypiella that had cadherin deletion mutations. Our findings suggest that cadherin promotes Bt toxicity by facilitating toxin oligomerization and demonstrate that the modified Bt toxins may be useful against pests resistant to standard Bt toxins.     

外源茉莉酸处理对Bt玉米直接防御物质含量及其相关基因表达的影响

 【目的】Bt（Bacillus thuringiensis）玉米（Zea mays L.）是全球商品化程度最快的抗虫转基因作物之一，协调利用其内在防御机制和人工导入抗性是目标害虫抗性风险综合管理和第2代抗虫转基因作物培育的主要策略之一。【方法】采用基因表达分析、化学物质分析和ELISA蛋白定量方法，研究外施信号物质茉莉酸对Bt玉米34B24 (Mon810)及其同源常规玉米34B23幼苗叶片直接防御物质含量及其相关基因表达的影响。【结果】外源茉莉酸处理能诱导34B24和34B23处理叶（第1叶）中LOX、PR-2a、MPI和PR-1基因的表达，第1叶丁布含量分别比对照增加63％和18％、总酚含量分别增加24％和12％。茉莉酸处理使34B24第1叶中的Bt蛋白含量增加了13%，但第2叶中的显著降低了27%。与34B23相比，茉莉酸对34B24的诱导作用更强，并具有系统性。【结论】人工外施茉莉酸的条件下，Bt玉米人工导入抗性（Bt基因）和自身化学防御过程之间的互作关系是协同的。     

Effect of Bt traits on transgenic rice’s growth and weed competitiveness

Transgene escape could lead to genetically modified rice establishing wild populations in the natural environment and competing for survival space with weeds. However, whether the expression of the Bacillus thuringiensis (Bt) gene in rice will alter the relationship between transgene plants and weeds and induce undesirable environmental consequences are poorly understood. Thus, field experiments were conducted to investigate the weed competitiveness and assess the ecological risk of transgenic Bt rice under herbicide-free and lepidopterous pest-controlled environments. Results showed that weed–rice competition in the direct-sowing (DS) field was earlier and more severe than that in the transplanting (TP) field, which resulted in a significant decrease in biomass and yield in DS. However, conventional Bt and non-Bt rice yield was not significantly different. The weed number, weed coverage ratio, and weed diversity of conventional Bt rice were significantly higher than those of non-Bt rice at the early growth and mature stages, especially in DS plots, suggesting that Bt traits did not increase the weed competitiveness of transgenic rice and had no negative effect on weed diversity. Grain yield and weed number varied between different hybrid rice lines, but those differences were insignificant between Bt and non-Bt rice. The number of insects increased with the increase of weeds in hybrid rice plots, whereas the insect number and diversity did not display a significant difference between Bt and non-Bt rice. Therefore, the ecological risk of transgenic Bt rice is comparable to non-Bt rice.     

靶标昆虫对转Bt基因作物产生抗性的机理及研究进展

总结了靶标昆虫对Bt毒素的抗性机理,系统综述了国内外靶标昆虫对转Bt基因作物抗性的研究现状,包括室内条件和大田条件下靶标昆虫对Bt毒素和转Bt基因作物形成抗性的研究和监测结果。