经遗传修饰生物体的研究进展及其释放后环境的影响

８０年代以来,以基因江程为代表的生物技术突飞猛进。转移不同性状的基因作物在美国被批准进入大田试验的有４０个以上的作物,包括小麦、玉米和水稻等４种谷类粮食作物,主要的纤维物棉花、蔬菜种类１０种以上,水果９种,其中还有油料作物,牧草和花卉等。到１９９６年６月已被批准进入市场的已有１８种,还有一批有待批准商业化。今年２月,美国农业部已第一次批准一种喂饲其它署期螨进入大田试验。第一个转基因线虫也正中申请向     

转基因作物与其野生亲缘种间的基因流

随着基因工程技术的突飞猛进,许多主要的农作物经过遗传修饰获得了优良的性状,并被批准进入市场。在美国,到１９９６年５月为止,经政府批准商业化的转基因作物已有７种;而在欧共体,仅在１９９１～１９９４年被释放作大田试验的转基因植物就达２９１个［１］。对于转...     

转基因植物的生态风险评价

自从１９８３年第一株转基因植物诞生以来,至今各种类型的转基因植物进入大田试验的已不计其数,近１０种转基因作物的产物已经商品化。与此同时,转基因植物向环境释放后可能带来的生态风险问题也越来越受到人们的重视。关于转基因植物的生态风险或对环境的危害,科学家提出了不同的概念和测试方法。生态毒理学的经验以及８０年代发展起来的,为作环境决策用的生态风险评价的经验可以借鉴以作转基因植物生态风险的评价。本文介绍了转基因植物对农田生态系统和自然生态系统可能带来的危害以及从基因、基因组、个体、种群以至生态系统等各级水平上危害测试的方法。对风险的判断作了详细的论述,对风险的管理也作了概略的介绍,并对生态风险评价当前发展的水平进行了讨论。     

北京大学的抗病毒转基因作物

从８０年代初美国科学家获得第一株转基因植物到现在,农业生物技术发展迅猛,已成为高新技术领域中进展最快的领域之一。到目前为止,已有大量的基因工程植物（包括许多农作物）从实验室走进了大田,甚至有不少具有不同性状的转基因植物已成为商品,进入市场。随着生物技...     

适合度分析对转基因逃逸潜在环境风险评价的意义北大核心CSCD

转基因作物的全球大规模种植引起了全世界的广泛关注甚至争议。经过遗传改良并具有自然选择优势的转基因作物进入商品化种植,可能将带来环境生物安全的顾虑。在这些生物安全的顾虑中,转基因通过花粉介导的基因漂移向栽培作物的野生近缘种逃逸及其导致的潜在环境风险,就是世人最为关注的环境生物安全问题之一。包括中国在内的许多国家,在转基因作物进行商品化生产之前都必须对转基因逃逸及其带来的潜在环境风险进行严格评价。按照风险评价的框架,转基因向野生近缘种逃逸及其带来潜在环境风险的评价包括3个连续的步骤:1)检测转基因漂移到作物野生近缘种的频率;2)分析转基因在野生近缘种中的表达;3)确定转基因对野生近缘种群体适合度和进化潜力的影响。大量基因漂移的研究结果已表明,转基因通过基因漂移向栽培作物邻近的野生近缘种群体逃逸难以避免,而转基因也会在作物的野生近缘种群体中正常表达。因此分析和评价转基因为野生近缘种带来的适合度效应,对于转基因逃逸及其环境风险的评价至关重要。对适合度的概念及其进化意义进行介绍,并对如何利用转基因的适合度效应分析转基因逃逸的环境风险,以及对此类环境风险进行研究和评价的具体方法予以介绍。上述知识和方法的掌握将有助于人们对转基因作物环境生物安全及其评价的全面理解。     

适合度分析对转基因逃逸潜在环境风险评价的意义

转基因作物的全球大规模种植引起了全世界的广泛关注甚至争议。经过遗传改良并具有自然选择优势的转基因作物进入商品化种植,可能将带来环境生物安全的顾虑。在这些生物安全的顾虑中,转基因通过花粉介导的基因漂移向栽培作物的野生近缘种逃逸及其导致的潜在环境风险,就是世人最为关注的环境生物安全问题之一。包括中国在内的许多国家,在转基因作物进行商品化生产之前都必须对转基因逃逸及其带来的潜在环境风险进行严格评价。按照风险评价的框架,转基因向野生近缘种逃逸及其带来潜在环境风险的评价包括3个连续的步骤:1)检测转基因漂移到作物野生近缘种的频率;2)分析转基因在野生近缘种中的表达;3)确定转基因对野生近缘种群体适合度和进化潜力的影响。大量基因漂移的研究结果已表明,转基因通过基因漂移向栽培作物邻近的野生近缘种群体逃逸难以避免,而转基因也会在作物的野生近缘种群体中正常表达。因此分析和评价转基因为野生近缘种带来的适合度效应,对于转基因逃逸及其环境风险的评价至关重要。对适合度的概念及其进化意义进行介绍,并对如何利用转基因的适合度效应分析转基因逃逸的环境风险,以及对此类环境风险进行研究和评价的具体方法予以介绍。上述知识和方法的掌握将有助于人们对转基因作物环境生物安全及其评价的全面理解。     

转基因油菜的基因流及生态风险

综合评述了转基因油菜的基因流及其生态风险.油菜作为最早的转基因作物之一目前已在加拿大和澳大利亚大面积商业化应用.(常)异花授粉作物油菜的天然异交率可达30%左右,也易与其它芸苔属作物杂交,因此转基因油菜的生态风险已引起各国科学家的高度重视.转基因油菜主要通过与其野生近缘种的花粉交换和与非转基因油菜的花粉交换两种方式进行花粉的输出.基因可能逃逸到相关野生近缘种,但在大田环境下能够得到杂种的可能性很小;由于基因的漂流在油菜田块间确实存在,因此在种植转基因油菜的过程中必须考虑其间隔距离.     

转基因作物生物安全:科学证据

通过对美国Web of Science数据平台的全部转基因作物生物安全SCI论文的检索,研究了有关转基因作物生物安全的科学证据。得出科学家比消费者更关心转基因技术的安全性;批准商业化生产的转基因技术经过了有史以来最为严格的生物学安全检验与检测,并建立了有史以来最为严格的监管体系;在所发表的全部9333篇转基因生物安全论文中,90%以上的论文证明转基因技术的安全性与传统非转基因作物无显著差异;而对于所有得出转基因食品不安全结论的论文的追踪研究发现,其研究结论被证明是在错误的研究材料或方法条件下得出的。     

转基因的逃逸及生态风险

转基因技术的发展为提高农作物产量和解决全球人口不断增长而引发的粮食问题带来了无限的机遇,但生物技术的应用和转基因作物的环境释放也带来了一系列生物安全问题．转基因产品是否会对植物、动物、人类健康、遗传资源和环境带来危害已成为公众关注的焦点．诸多生物安全问题中最引人注目的问题之一就是转基因的逃逸及其可能导致的生态风险．文中就转基因逃逸的可能性和逃逸的不同途径、转基因逃逸后可能导致的各种生态风险、转基因逃逸的不同控制方法以及转基因作物安全距离设立应该考虑的因素等问题进行了讨论,旨在了解转基因作物的环境释放和外源基因的逃逸可能导致的生物安全问题,以及如何控制和避免转基因逃逸．     

转基因植物及其安全性

所谓转基因植物,是指运用DNA重组技术将外源基因整合到受体植物基因组中,从而改变其基因组成,这种基因组结构发生改变的植物及其后代就是转基因植物。1983年,世界上第一株转基因植物,是由美国科学家研发出来的转基因烟草。1986年首批转基因作物被批准进行小规模田间试     

Spatial processes in the evolution of resistance in Helicoverpa zea (Lepidoptera: Noctuidae) to Bt transgenic corn and cotton in a mixed agroecosystem: a biology-rich stochastic simulation model

A simulation model is developed to examine the role of spatial processes in the evolution of resistance in Helicoverpa zea populations to Bt corn and Bt cotton. The model is developed from the stochastic spatially explicit Heliothis virescens model described by Peck et al. (1999), to accommodate a spatial mix of two host crops (corn and cotton), and to reflect the agronomic practices, as well as the spatial and temporal population dynamics of H. zea, in eastern North Carolina. The model suggests that selection for resistance is more intense in Bt cotton fields than in Bt corn fields. It further suggests that local gene frequencies are highly dependent on local deployment levels of Bt crops despite the high mobility of the adult insects. Region-wide average gene frequencies depend on the region-wide level of Bt deployment, so incomplete technology adoption slows the rate of resistance evolution. However, on a local scale, H. zea populations in clusters of fields in which Bt use is high undergo far more rapid evolution than populations in neighboring clusters of fields in which Bt use is low. The model suggests that farm-level refuge requirements are important for managing the risk of resistance. The model can be used as an aid in designing plans for monitoring for resistance by suggesting the appropriate distribution of monitoring locations, which should focus on areas of highest Bt crop deployment. The findings need to be placed in the context of the input parameters, many of which are uncertain or highly variable in nature, and therefore, a thorough sensitivity analysis is warranted.     

壳聚糖对玉米生长的调节作用

应用壳聚糖衍生物羧甲基壳聚糖(NCMC)水溶液处理玉米种子,能够促进玉米种子的萌发,提高发芽势和发芽率.处理玉米果穗能够提高玉米未成熟籽粒的可溶性蛋白以及成熟种子的贮藏蛋白含量.以上结果表明,羧甲基壳聚糖对作物生长有调节功能.本文还初步研究了羧甲基壳聚糖对作物生长调控的机理.     

取食Bt棉与玉米的越冬代棉铃虫抗寒性特征比较

【目的】针对由Bt棉花和玉米构成的华北农田景观, 探讨不同寄主作物对棉铃虫 Helicoverpa armigera 越冬抗寒的影响。【方法】2013年在河北廊坊科研中试基地的作物田中将棉铃虫幼虫接到Bt棉和玉米上, 比较取食不同作物后棉铃虫的化蛹率、存活率和越冬蛹羽化率;在室内控制条件下分别用棉蕾和鲜玉米粒饲喂棉铃虫幼虫。 测定滞育蛹和非滞育蛹的鲜重、干重、以及脂肪、糖原和低分子物质含量等指标, 比较取食不同作物后棉铃虫的抗寒能力。【结果】取食玉米的棉铃虫滞育蛹干重（117.5 mg）、脂肪含量（457.2 μg/mg DW）以及海藻糖浓度（86.45 μg/g）均显著高于取食Bt棉的棉铃虫滞育蛹干重（56.6 mg）、脂肪含量（239.6 μg/mg DW）以及海藻糖浓度（13.87 μg/g）;取食玉米的棉铃虫冰点(-10.2℃)显著低于取食Bt棉的棉铃虫冰点(-6.5℃)。【结论】结果表明取食玉米更加有利于棉铃虫越冬。 据历史数据, 近年来玉米种植面积不断增加, 这将提高棉铃虫成功越冬比率, 对棉铃虫种群扩张起到促进作用, 因此注重玉米上棉铃虫的防治尤为重要。     

Quantification of diapausing fourth generation and suicidal fifth generation cotton bollworm, Helicoverpa armigera, in cotton and corn in northern China

Cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), is a major pest of cotton and corn crops in northern China. A phenological differentiation between fourth generation cotton bollworms from cotton and those from corn fields was observed in northern China during 1999–2000. The proportion of pupation in late fall was marginally higher in cotton fields compared to that in corn fields; however, the proportions of fall emergence of moths from cotton fields were significantly higher than those from corn fields. The proportion of spring emergence of moths was also significantly higher for larvae collected from cotton (28.0%) than from corn (14.5%). The overwintering duration of females was significantly shorter than that of males in both crops. Moreover, the overwintering duration of bollworm populations from cotton was significantly longer than that from corn. The early spring population of H. armigera came from both cotton and corn fields, but the spring emergence of moths from larvae collected from cotton took about 5 days longer to reach 100% emergence compared to that from corn.     

Using stable isotope analysis to examine fall armyworm (Lepidoptera: Noctuidae) host strains in a cotton habitat

Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), or fall armyworm, is an important agricultural pest of several crops in the Western Hemisphere, including cotton (Gossypium L.). Two morphologically identical host strains of fall armyworm exist that differ in plant host use and habitat distribution. The corn-strain is a primary pest of corn, Zea mays L., whereas the rice-strain is the majority population infesting rice (Oryza spp.) and turfgrass (Cynodon spp.). With the increased use of Bacillus thuringiensis (Bt) toxin-expressing cotton varieties and the necessity of ensuring adequate refuge areas to prevent the spread of Bt toxin resistance, it is crucial to identify the alternative plant hosts available for the fall armyworm population infesting cotton. Stable isotope analysis combined with the molecular analysis of strain-specific markers was used to investigate whether one or both strains routinely develop on cotton grown in the Mississippi delta. We found that the majority of fall armyworm adults present during the early cotton growing season arose from C4 plants (e.g., corn and sorghum, Sorghum vulgare Pers.) and that the only strain likely to be developing on cotton (a C3 plant) in substantial numbers was the corn-strain. The population distribution patterns observed were consistent with corn providing an important refuge for the fall armyworm strain infesting cotton and suggested that late season populations in the Mississippi delta may be migrants from more northern corn areas.     

Host plant association and genetic differentiation of corn and rice strains of Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) in Colombia

Spodoptera frugiperda (Smith) is a polifagous insect of major economic impact in the western hemisphere and exhibits two strains (i.e., corn and rice) that are morphologically identical but differ in ecology, genetics and physiology. In this work we identified these strains and their respective hybrids by using a PCR-RFLP of the COI gene and PCR of the tandem region FR. Moreover, we performed a population structure analysis by using 253 larvae from Tolima, a region where S. frugiperda is a pest on corn, rice, sorghum and cotton. Corn strain was found on 42% in corn, 34% in cotton, 19% in sorghum and 0.04 % in rice and rice strain on 35% in corn, 0.06% in cotton, 0.06% in sorghum and 53% in rice, demonstrating that corn strain specificity is superior to rice strain. Hybrids between these strains were more abundant in corn. The distributions on their host plants reflect a population genetic differentiation in S. frugiperda with values of PhiPT (COI) = 0.31, P < 0.0001, PhiPT (FR) = 0.17, P < 0.0001 for all crops and PhiPT (COI) = 0.42, P < 0.01, PhiPT (FR) = 0.13, P < 0.01 for the sixteen sampled farms. The dendrograms showed two clusters representing both strains. The results obtained in this study suggest that the management of this insect must differ on each host plant, given the specialization that both strains present, particularly in corn and rice.     

转基因作物对生物多样性的影响

转基因作物对生物多样性的影响是重要的环境问题之一,近年来,已有这类实验的报道。夏敬源等的研究说明大田种植转基因Bt虫棉花对棉铃虫优势寄生性天敌齿唇姬蜂（Campoletis chlorideae）和侧沟绿茧蜂（Microplitis sp.）的寄生率、羽化率和蜂茧质量造成严惩的危害。国际上一些昆虫学家也做了很好的工作,尤其1999年5月Losey在Nature上发表转基因Bt抗虫玉米在实验室水平上引起大斑蝶死亡报道后,世界范围内引起极大的反响,在有关经遗传修饰生物体（GMOs）的潜在生态风险和人体健康影响的问题上美国始络抱抵制的强硬态度,这次也开始有所所松动。两个有影响的美国玉米加工公司富布不再接受欧盟拒绝进口的转基因玉米品种。欧盟宣布在进一步研究得到结论前冻结转基因作物产品进口的审批。欧盟所属有关国家有的禁止进口,有的反对欧盟审批。科技界及公众众说纷纭。建议我国政府要加强GMOs潜在生态风险及对公众健康的研究及商业化生产后的监测。     

Influence of corn on stink bugs (Heteroptera: Pentatomidae) in subsequent crops

In southeastern United States farmscapes, corn, Zea mays L., is often closely associated with peanut, (Arachis hypogaea L.), cotton, (Gossypium hirsutum L.), or both. The objective of this 3-yr on-farm study was to examine the influence of corn on stink bugs (Heteroptera: Pentatomidae), Nezara viridula (L.), and Euschistus servus (Say), in subsequent crops in these farmscapes. Adults of both stink bug species entered corn first, and seasonal occurrence of stink bug eggs, nymphs, and adults indicated that corn was a suitable host plant for adult survival and nymphal development to adults. Stink bug females generally oviposited on cotton or peanut near the interface, or common boundary, of the farmscape before senescence of corn, availability of a new food, or both. Adult stink bugs dispersed from crop to crop at the interface of a farmscape in response to senescence of corn, availability of new food, or both. In corn-cotton farmscapes, adult stink bugs dispersed from senescing corn into cotton to feed on bolls (fruit). In corn-peanut farmscapes, adult stink bugs dispersed from senescing corn into peanut, which apparently played a role in nymphal development in these farmscapes. In the corn-cotton-peanut farmscape, stink bug nymphs and adults dispersed from peanut into cotton in response to newly available food, not senescence of peanut. Stink bug dispersal into cotton resulted in severe boll damage. In conclusion, N. viridula and E. servus are generalist feeders that exhibit edge-mediated dispersal from corn into subsequent adjacent crops in corn-cotton, corn-peanut, and corn-peanut-cotton farmscapes to take advantage of suitable resources available in time and space for oviposition, nymphal development, and adult survival. Management strategies for crops in this region need to be designed to break the cycle of stink bug production, dispersal, and expansion by exploiting their edge-mediated movement and host plant preferences.     

种植制度对江苏省棉田杂草群落影响的研究

 经连续5年对江苏省主棉区水旱轮作及旱连作两种种植制度下的棉田杂草种群密度及草害优势度级数进行定田调查,通过时间和空间上的比较统计分析,研究了棉田杂草群落演替趋势及草害发生规律。研究结果表明,种植制度与江苏省棉田杂草群落的组成和草害发生程度紧密相关。在水旱轮作棉田中,随着棉花(Gossypium hirsutum)种植年数的增加,喜湿性杂草稗草(Echinochloa crusgalli)等优势度值逐渐减少,喜旱性杂草马唐(Digitaria sanguinalis)等优势度值逐渐提高,它们之间存在显著的线性关系。旱连作棉田以喜旱性杂草为主,发生量较大,草害较重,年际间杂草群落变化较小。另外,水旱轮作和旱连作棉田之间的杂草群落结构和种群数量差异显著。而地理区域差异的影响明显小于轮作制度差异导致的影响。     

STUDY ON THE GENETIC VARIATION OF THE COTTON BOLLWORM HELICOVERPA ARMIGERA (HÜBNER) POPULATIONS IN CHINA*

Abstract Population genetic variations of Helicoverpa armigera (Hiibner) over different major cotton growing regions were analyzed by DNA polymorphism amplified with four simple repetitive sequence primers. The results showed that the laboratory population had relatively lower genetic variation than natural populations. The genetic variation between natural populations was not significant and genetic variation existed in the same location from different years, indicating frequent migration among natural cotton bollworm populations. Cluster analysis indicated that individuals from Chaoyang of Liaoning Province (CY), Gaotang of Shandong Province (GT) and Dafeng of Jiangsu Province(DF) were more mixed each other, which suggested that CY population might have higher gene flow with GT and DF populations, especially with GT population. It supports the theory that the cotton bollworm in Northeast China came from Shandong and Hebei Provinces. This result also demonstrated that the molecular makers in this study are sensitive to detect population genetic structure changes.