转基因抗虫棉经济效益可持续性研究

虽然种植转基因抗虫棉的短期经济效益已经被广泛证实了,然而其经济效益的可持续性问题仍待研究.对其经济效益可持续性的质疑,也成为近年来对转基因作物争论的焦点.本文首先通过构建和分析理论模型来回答这一问题.定性分析结果表明,种植转基因抗虫棉能间接导致次要害虫农药使用量的上升.本文用符合中国实际的生物和经济学参数来模拟棉花生产.数值模拟结果显示,次要害虫农药使用量的上升并不足以抵消种植抗虫棉带来的农药节省.而且由于有大量自然避难所的存在,棉铃虫对转基因蛋白的抗性在大田中并没有广泛建立起来.总之,本研究表明种植抗虫棉的经济效益不但在数量上是显著的,在时间上也是可持续的.     

转基因抗虫棉生物安全评价研究进展

概述了转基因抗虫棉的推广应用现状,并从基因漂移,靶标害虫对转基因抗虫棉的抗性及治理对策、对非靶标昆虫的影响、对土壤生态系统的影响及其产品的食品安全性评价几个方面对近年来国内外对转基因抗虫棉的生物安全性研究做了综述。     

转Bt基因棉花生态风险评价的研究进展

转Bt基因抗虫棉(Gossypium spp.)是目前国内释放面积最大的转基因作物,其生态风险问题从一开始就受到密切的关注.从生态风险评价的角度,分转基因棉花中Bt杀虫蛋白的时空表达及其对害虫的控制效果、Bt基因通过花粉传播而扩散的风险、害虫对Bt棉花抗性的进化风险、Bt棉花对非目标生物体影响的风险等几个方面,综述了Bt棉安全性评价的最新研究进展,为生物安全管理提供咨询意见,并提出了目前针对Bt棉亟待研究的内容.期望本文能够为推动生物安全的研究和生物技术的发展做出一定的贡献.     

转基因的生物安全问题

国家环保总局 2 0 0 2年 5月 2 1日举行国际生物多样性日新闻发布会 ,会议谈到了国际社会目前十分关注的转基因生物及其产品对生物多样性、生态环境和人体健康可能产生的潜在影响 ,其涉及的主要问题有 :1、转基因生物对非目标生物的影响。释放到环境中的抗虫和抗病类转基因植物 ,除对害虫和病菌致毒外 ,对环境中的许多有益生物也将产生直接或间接的不利影响 ,甚至会导致一些有益生物死亡。2、增加目标害虫的抗性和进化速度。研究表明 ,棉铃虫已对转基因抗虫棉产生抗性 ,专家警告 ,如果这种具有转基因抗性的害虫变成对转基因表达蛋白具有抗性…     

靶标害虫对Bt玉米的抗性发展和治理策略

全生育期有效表达Bt杀虫蛋白的转基因抗虫玉米为靶标害虫的防治提供了新途径。但是,靶标害虫抗性种群的发展严重威胁了转基因抗虫玉米的可持续应用。截止到2018年,已经有13例报道表明靶标害虫对转基因抗虫玉米产生了田间抗性;5例监测结果表明靶标种群没有降低对Bt玉米的敏感性,其中包括转vip3Aa玉米。抗性治理策略成功的关键主要包括:Bt杀虫蛋白的高剂量表达、靶标害虫的隐性遗传、初始抗性等位基因频率较低、不完全抗性、适合度代价等。当抗性为非隐性遗传时,可以通过增加庇护所的种植面积达到延缓抗性发展的目的。     

转基因741杨节肢动物群落主要害虫及天敌的动态变化

在时间序列过程中,转基因741杨对目标害虫鳞翅目食叶害虫表现出持续的抗性,其数量明显减少,高抗和中抗741杨之间差异不大.研究表明,转基因741杨对目标昆虫和非目的植食性害虫存在负效应,而对天敌和中性节肢动物组成和发生无明显负作用.因而在制定害虫综合治理策略和途径上宜采取与对照741杨不同的措施,抗性株系应以生态调控为主.     

转基因植物的生态风险

转基因植物已在很多国家大规模商业化种植,并且取得了显著的经济效益。同时有关转基因植物潜在的生态风险已引起广泛的关注。本文从转基因植物人侵危害、对非靶标有益生物直接和间接的影响、害虫对抗虫转基因植物产生抗性、抗病毒转基因植物带来的潜在风险等方面论述了转基因植物可能潜在的生态安全性问题。     

转Bt基因抗虫水稻的研究进展与生态安全评价

表达杀虫蛋白的转Bt基因植物正在改革着现代农业．综述了国内外转Bt基因水稻及其抗虫性的研究进展及水稻害虫对Bt水稻的抗性风险及抗性管理策略,提出了对转基因Bt水稻进行生态安全风险评价的具体内容．     

生物技术与棉花生产

１　转基因棉花的研究自８０年代末以来,棉铃虫在我国大部分地区持续性大发生或暴发,给棉花生产带来巨大经济损失。对此,人们正积极探讨有效防治棉铃虫的方法,广泛采用化学防治、生物防治、农业防治等措施。虽取得了一定的成效,但仍没有达到有效防治的目的。化学农药的使用不仅增加了植棉成本、挫伤了棉农的植棉积极性,而且还造成环境污染,破坏生态平衡并使害虫抗药性提高。为了有效解决这一关系环境与发展的问题,国家“８６３”计划在生物领域加大了转基因抗虫棉的研究。转基因抗虫棉是运用现代生物技术和传统育种相结合,将抗棉铃…     

甜菜夜蛾的抗性及抗性机理研究进展

甜菜夜蛾Spodoptera exigua(Hübner)是世界性农业害虫,近年来在我国由次要害虫上升为主要害虫。甜菜夜蛾对很多种化学杀虫剂和生物杀虫剂产生了抗性。本文分别阐述了甜菜夜蛾对常用杀虫剂如有机磷类、拟除虫菊酯类、氨基甲酸酯类、生长调节类杀虫剂、Bt杀虫剂等的抗性发展现状,并且对抗药性机理进行了总结,提出了抗性治理措施。     

转抗虫基因植物生态安全性研究进展

转抗虫基因植物如Bt棉花等已在美国、中国和澳大利亚等国家大规模商业化种植 ,有关转抗虫基因植物潜在的生态风险已引起广泛的关注。该文综述了转抗虫基因植物研究应用现状与安全性研究进展。主要内容包括 :转抗虫基因植物的种类及其对靶标害虫的抗性 ,对非靶标害虫和天敌发生的影响 ,对农田生态系统生物多样性的影响 ,靶标昆虫的抗性治理及转抗虫基因植物的基因漂移等     

Early warning of cotton bollworm resistance associated with intensive planting of Bt cotton in China

Transgenic crops producing Bacillus thuringiensis (Bt) toxins kill some key insect pests, but evolution of resistance by pests can reduce their efficacy. The predominant strategy for delaying pest resistance to Bt crops requires refuges of non-Bt host plants to promote survival of susceptible pests. To delay pest resistance to transgenic cotton producing Bt toxin Cry1Ac, farmers in the United States and Australia planted refuges of non-Bt cotton, while farmers in China have relied on "natural" refuges of non-Bt host plants other than cotton. Here we report data from a 2010 survey showing field-evolved resistance to Cry1Ac of the major target pest, cotton bollworm (Helicoverpa armigera), in northern China. Laboratory bioassay results show that susceptibility to Cry1Ac was significantly lower in 13 field populations from northern China, where Bt cotton has been planted intensively, than in two populations from sites in northwestern China where exposure to Bt cotton has been limited. Susceptibility to Bt toxin Cry2Ab did not differ between northern and northwestern China, demonstrating that resistance to Cry1Ac did not cause cross-resistance to Cry2Ab, and implying that resistance to Cry1Ac in northern China is a specific adaptation caused by exposure to this toxin in Bt cotton. Despite the resistance detected in laboratory bioassays, control failures of Bt cotton have not been reported in China. This early warning may spur proactive countermeasures, including a switch to transgenic cotton producing two or more toxins distinct from Cry1A toxins.     

Increased frequency of pink bollworm resistance to Bt toxin Cry1Ac in China

Transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt) kill some key insect pests, but evolution of resistance by pests can reduce their efficacy. The main approach for delaying pest adaptation to Bt crops uses non-Bt host plants as "refuges" to increase survival of susceptible pests. To delay evolution of pest resistance to transgenic cotton producing Bt toxin Cry1Ac, the United States and some other countries have required refuges of non-Bt cotton, while farmers in China have relied on "natural" refuges of non-Bt host plants other than cotton. The "natural" refuge strategy focuses on cotton bollworm (Helicoverpa armigera), the primary target of Bt cotton in China that attacks many crops, but it does not apply to another major pest, pink bollworm (Pectinophora gossypiella), which feeds almost entirely on cotton in China. Here we report data showing field-evolved resistance to Cry1Ac by pink bollworm in the Yangtze River Valley of China. Laboratory bioassay data from 51 field-derived strains show that the susceptibility to Cry1Ac was significantly lower during 2008 to 2010 than 2005 to 2007. The percentage of field populations yielding one or more survivors at a diagnostic concentration of Cry1Ac increased from 0% in 2005-2007 to 56% in 2008-2010. However, the median survival at the diagnostic concentration was only 1.6% from 2008 to 2010 and failure of Bt cotton to control pink bollworm has not been reported in China. The early detection of resistance reported here may promote proactive countermeasures, such as a switch to transgenic cotton producing toxins distinct from Cry1A toxins, increased planting of non-Bt cotton, and integration of other management tactics together with Bt cotton.     

Advances in Transgenic Research for Insect Resistance in Sugarcane

The first phase of transgenic research in sugarcane concentrated on the development and evaluation of transgenic lines transformed for resistance to biotic stresses, particularly diseases and insect pests. Sugarcane is attacked by a range of insects including tissue borers, sucking pests and canegrubs. Losses due to these pests are estimated to be around 10%. Although chemical control and integrated pest management are regularly practiced for the control of insect pests, success is often limited due to practical difficulties. The genetic complexity of sugarcane coupled with the non-availability of resistance genes in the germplasm has made conventional breeding for insect resistance difficult. In this context, transgenic technology has become a handy tool for imparting insect resistance to an elite variety which is otherwise superior for most other agronomic traits. A number of transgenic sugarcane lines have been developed with genes expressing Cry proteins, proteinase inhibitors or lectins resistant to borers, sucking insects or grubs. While commercializing transgenic lines, issues such as higher and stable transgene expression, preparedness for resistance management and non-target effects need to be addressed. To manage the constant threat of resistance development in target insects, it is imperative to deploy field-level strategies taking clues from other crops coupled with the search for new potent replacement molecules for transformation.     

转基因棉花Bt毒蛋白的表达及其生态学效应

苏云金杆菌毒蛋白 (Bacillusthuringiensisgtoxicprotein)基因导入棉花植株后获得的转Bt棉可以特异性地毒杀棉铃虫及鳞翅目的一些其它害虫 ,有效地保护棉花植株不受此类棉花害虫的危害。Bt毒蛋白在棉花植株中的表达受一些内外界因素的影响而呈明显的时空变化。转Bt棉除了严重影响靶标害虫自身外 ,还能对其它一些非靶标昆虫和环境产生影响。另外 ,该文还对害虫对Bt棉的抗性以及防止害虫产生抗性的治理对策进行了综述     

Population dynamics of Spodoptera litura (Lepidoptera: Noctuidae) on Bt cotton in the Yangtze River Valley of China

Genetically modified cotton that produces a crystalline protein from Bacillus thuringiensis subsp. kurstaki (Berliner) (Bt) has been widely deployed to manage lepidopteran insect pests in cotton growing areas worldwide. However, susceptibility of different insect species to Bt protein varies, which may affect lepidopteran pest populations in the field. Studies on effects of two transgenic cotton lines (BG1560 and GK19) carrying a Cry1A gene on common cutworm Spodoptera litura F. (Lepidoptera: Noctuidae), were conducted during 2002-2005 in the cotton planting region of the Yangtze River valley of China. Results showed that common cutworm larvae had low susceptibility to Bt cotton. There was no significant difference in larval population densities in conventional and Bt cotton fields. However, the larval populations of the insect on conventional plants treated with chemical insecticides for control of target pest of Bt cotton were significantly lower than that in Bt cotton fields. These results indicated that the common cutworm was the potential to become a major and alarming pest in Bt cotton fields, and therefore efforts to develop an effective alternative management strategy are needed.     

Early detection of field-evolved resistance to Bt cotton in China: cotton bollworm and pink bollworm

Transgenic crops producing Bacillus thuringiensis (Bt) toxins kill some major insect pests, but pests can evolve resistance and thereby reduce the effectiveness of such Bt crops. The main approach for slowing pest adaptation to Bt crops uses non-Bt host plants as "refuges" to increase survival of susceptible pests. To delay evolution of pest resistance to cotton producing Bt toxin Cry1Ac, several countries have required refuges of non-Bt cotton, while farmers in China have relied on "natural" refuges of non-Bt host plants other than cotton. This strategy is designed for cotton bollworm (Helicoverpa armigera), which attacks many crops and is the primary target of Bt cotton in China, but it does not apply to pink bollworm (Pectinophora gossypiella), which feeds almost entirely on cotton in China. Here we review evidence of field-evolved resistance to Cry1Ac by cotton bollworm in northern China and by pink bollworm in the Yangtze River Valley of China. For both pests, results of laboratory diet bioassays reveal significantly decreased susceptibility of field populations to Cry1Ac, yet field control failures of Bt cotton have not been reported. The early detection of resistance summarized here may spur countermeasures such as planting Bt cotton that produces two or more distinct toxins, increased planting of non-Bt cotton, and integration of other management tactics together with Bt cotton.     

棉铃虫对转Bt基因棉的抗性及其治理策略研究进展棉铃虫对转Bt基因棉的抗性及其治理策略研究进展

简述了苏云金杆菌Bacillus thuringiensis（Bt）毒素的作用方式及杀虫机理,分析了Bt棉种植过程中面临的生态风险。综述了昆虫对Bt毒素的抗性机理、监测方法及治理策略方面的研究进展。棉铃虫对Bt棉的抗性可能主要与中肠上皮细胞膜上的特异性结合受体中结合位点的改变有关。在多种抗性治理策略中,庇护所策略被公认为是目前最有效的并已广泛采用的抗性治理措施。应针对Bt棉在我国的种植情况,在棉铃虫还未在田间表现出抗性以前,制定合理的抗性预防、治理措施。     

Effects of transgenic Bt cotton on the population density, oviposition behavior, development, and reproduction of a nontarget pest, Adelphocoris suturalis (Hemiptera: Miridae)

Transgenic cotton has shown great promise for the control of target pest insects; however, frequent outbreaks of nontarget pest mirids has been recorded in recent years in northern China. To test the hypothesis that transgenic cotton contributes to nontarget pest outbreaks, we studied the impact of transgenic Bt cottons (both Bt and Bt + CpTI) on the fitness of nontarget pest Adelphocoris suturalis Jakovlev. No significant differences were detected between population densities of A. suturalis in unsprayed nontransgenic cottons and in unsprayed transgenic Bt cottons in 2007, 2008, and 2009. No difference in preferred oviposition site or egg production was detected between transgenic and nontransgenic cottons in both free choice and no choice tests. No difference in life table parameters was detected for A. suturalis between Bt cottons and nontransgenic cottons. All these results indicated that transgenic crops did not contribute to the nontarget pest outbreaks when being compared with their parental lines. The possible reasons for intensified pest status of A. suturalis, such as decrease of pesticide application, deficient natural enemies, and area-wide shift of cotton varieties, were discussed.     

Insect resistance to Bt crops: evidence versus theory

Evolution of insect resistance threatens the continued success of transgenic crops producing Bacillus thuringiensis (Bt) toxins that kill pests. The approach used most widely to delay insect resistance to Bt crops is the refuge strategy, which requires refuges of host plants without Bt toxins near Bt crops to promote survival of susceptible pests. However, large-scale tests of the refuge strategy have been problematic. Analysis of more than a decade of global monitoring data reveals that the frequency of resistance alleles has increased substantially in some field populations of Helicoverpa zea, but not in five other major pests in Australia, China, Spain and the United States. The resistance of H. zea to Bt toxin Cry1Ac in transgenic cotton has not caused widespread crop failures, in part because other tactics augment control of this pest. The field outcomes documented with monitoring data are consistent with the theory underlying the refuge strategy, suggesting that refuges have helped to delay resistance.