转基因植物重组DNA和表达蛋白的环境分子行为

转基因植物的安全性已经在全球范围内引起了普遍关注。本文从分子水平上就转基因植物的重组DNA在环境中的降解动态、转基因植物重组DNA在生物体内的传递、转基因植物杀虫蛋白在环境中的降解及在食物链间的传递等有关研究进展作一简要介绍。     

侵染甘薯的DNA病毒研究进展

甘薯是重要的粮食作物和食品加工及工业原料。我国是世界上最大的甘薯生产国。病毒病是甘薯上的重要病害,目前世界上已报道的侵染甘薯的DNA病毒主要归属于双生病毒科Geminiviridae和花椰菜花叶病毒科Caulimoviridae。近年来,双生病毒等DNA病毒严重影响我国甘薯的产量、品质以及食品加工产业。本文简介了甘薯在我国的重要地位和种植情况;具体介绍了侵染甘薯的菜豆金色花叶病毒属Begomovirus、玉米线条病毒属Mastrevirus及杆状DNA病毒属Badnavirus的病毒特征、分子变异、分类现状和检测方法。结合甘薯生产的实际情况,提出了目前甘薯DNA病毒研究中存在的问题及思考。本文旨在为我国甘薯DNA病毒病的综合防控提供理论依据。     

DNA条形码技术研究进展及其在植物检疫中的应用展望

DNA条形码是一种新的生物分类学方法,它通过特有的一段DNA序列来识别每种生物。与传统鉴定技术相比,利用该技术进行生物物种鉴定具有快速、准确、简便、易行等优点。该技术在出入境植物检疫中将得到广泛应用。     

转Bt基因作物对植物—害虫—天敌食物链的影响

种植转Bt基因作物已经成为当前及未来农业的发展趋势。转Bt基因作物可以有效控制棉铃虫（〖WTBX〗Helicoverpa armigera〖WTBZ〗）、玉米螟（〖WTBX〗Ostrinia furnacalis〖WTBZ〗）等多种靶标害虫。但研究表明Bt作物的种植会改变害虫演化地位,并且Bt毒素可能沿着食物链传递,而对天敌构成潜在的威胁。基于Bt作物对植物—害虫—天敌食物链上各个营养级的影响研究,本文重点分析了Bt毒素对天敌种群结构及生物学的影响。     

不同Bt杀虫蛋白通过食物链对大草蛉的影响

为了明确目前转基因抗虫植物中表达的Bt蛋白对农田重要捕食性天敌大草蛉的生态安全性,采用三级营养食物链评价体系,分别以对供试Bt蛋白Cry1Ac、Cry1F和Cry2Ab具有抗性的靶标害虫或不敏感的非靶标害虫作为大草蛉的猎物,研究了供试3种蛋白对大草蛉的影响。结果表明,当大草蛉以抗性棉铃虫（抗Cry1Ac或Cry2Ab）或抗性玉米螟（抗Cry1F）为猎物时,供试3种Bt蛋白通过食物链对大草蛉幼虫（4龄幼虫重量和幼虫发育至蛹历期）、蛹（化蛹率、蛹重和蛹发育历期）及成虫（羽化率、雌虫重量、雄虫重量和单雌产卵量）的生长发育及产卵量均无显著影响;同样地,当大草蛉以对3种Bt蛋白不敏感的非靶标昆虫——绿盲蝽作为猎物时,通过食物链传递的Bt蛋白对大草蛉生长发育及繁殖也无显著影响。因此,目前转基因棉花、玉米或水稻中广泛表达的Cry1Ac、Cry1F和Cry2Ab蛋白,通过三级营养食物链,对大草蛉生长发育及繁殖均无潜在毒性。     

黑麦草属DNA条形码鉴定技术研究

以毒麦、田毒麦、多花黑麦草、多年生黑麦草、硬直黑麦草、高羊茅与狗牙根等禾本科的7种植物为材料,拟采用 DNA 测序、特异性位点比对、种间遗传距离测定、建立系统树等分析候选 DNA 条形码 psbA-trnH 鉴别黑麦草属常见植物的能力。实验结果表明,以 psbA-trnH 为 DNA 条形码时,建立的系统发育树能较好区分毒麦和田毒麦与其他几种植物。psbA-trnH 序列可以作为黑麦草属植物的潜在条形码。     

植物病原细菌DNA分子检测技术

在DNA检测技术建立之前,种子上的病菌及未显症的病害的快速检测和鉴定几乎是不可能的.随着DNA检测技术的发展,在隐症植物材料上的病害检测变得快速可靠.本文主要介绍DNA检测技术在植物病原细菌检测中的应用.     

植物病原细菌DNA条形码检测技术

植物病原细菌是植物病原菌的重要组成部分,DNA 条形码技术在植物病原细菌的鉴定中应用非常普遍,本文综述了在植物病原细菌鉴定中常用的基因及目前应用的一些数据库,认为在细菌鉴定中比较适用的方法为先通过16S rRNA 基因分析确定到属,然后通过多态性更强的基因或多个基因的联合应用鉴定到种或种下阶元。DNA 条形码技术可以作为常规检测技术的一个强有力补充,提高病原菌鉴定的标准化与速度,尤其对检疫性病原细菌的鉴定具有重要作用。     

DNA条形码的应用进展及讨论

DNA条形码(DNA Barcoding)是近几年来国际生物学研究的热点之一。但是在国内,相关概念还存在不同程度的模糊,不利于研究工作的进一步开展。本文在对DNA条形码与DNA分类(DNA Taxonomy)两个不同概念进行辨析的基础上,回顾与总结了DNA条形码的产生背景与应用进展,并对DNA条形码目前所面临的基因交流、取样、计算方法等问题进行了总结和分析,最后对DNA条形码研究前景进行了展望。     

基于DNA条形码技术对新疆罂粟科部分植物系统发生分析

以新疆地区4属5种罂粟科植物为研究对象,利用DNA测序技术测定植物叶绿体rbcL基因、核基因ITS,并研究将这两种特定基因联合作为DNA条形码在识别新疆地区罂粟科植物的可行性和有效性。对15条新疆罂粟科植物的ITS-rbcL序列进行信息分析,发现其基因片段多态性位点较多,种内平均遗传距离小于种间。另外,以4种毛茛属植物做外类群对31种罂粟科植物进行聚类分析。结果显示:同属植物基本聚在一起,说明这一联合片段用来鉴定罂粟科植物中属的分类阶元是可行的。所选择的ITS-rbcL片段对罂粟科植物的分类鉴定有一定的参考价值。通过研究还发现,新疆鳞果海罂粟与伊犁秃疮花的亲缘关系较该属其他植物更为接近;新疆重点保护植物红花疆罂粟与黑环罂粟为近缘种;rbcL基因由于其保守度较高,并不适合作罂粟科植物的进化标记基因。     

Investigations of Rats in Ricefields Demonstrating an Effective Control Method Giving Substantial Yield Increase

Abstract

The influence of ecosystems on cassava (Manihot escutenta Crantz) cultivars and the possible reasons for this are discussed, as well as the effect of distinct negative production factors, i.e., edaphic and climatic constraints, and disease and pest stresses, on regional and introduced varieties. Decentralised improvement programmes in different ecosystems based on 10 years research are suggested, and are selected according to socioagro-economic studies related to actual and/or potential production of cassava.     

Impact of cypermethrin on feeding behaviour and mortality of the spider Pardosa amentata in arenas with artificial 'vegetation'

Pesticides can modify invertebrate movement and feeding behaviour which could reduce predation in agroecosystems. Previous assays have exposed the spider Pardosa amentata (Clerck) to the synthetic pyrethroid cypermethrin and monitored prey items consumed in small containers (requiring very little movement to capture prey). The current study used larger arenas containing artificial 'vegetation' (a plastic analogue) to encourage spiders to hunt and capture prey. The period 24 h after exposure produced greatest variability in prey item consumption between treatments and was used to examine treatment effects. At this time, cypermethrin reduced prey consumption rates but these effects did not persist. Findings did not suggest that the presence of artificial vegetation in arenas modified prey consumption rates, which was consistent for individuals treated with cypermethrin and a control group. This is despite the majority of pesticide-treated individuals exhibiting both ataxia and paralysis of the hind legs (these effects persisting for a maximum of 3 and 6 days respectively). These findings were consistent for both sexes. Spider longevity under starvation conditions was not significantly reduced by cypermethrin exposure but overall females survived longer than males. The findings are discussed in the context of the arenas used and the ecology of this common predator.     

DNA分子检测技术在节肢动物食物网结构解析中的应用

生态系统中节肢动物食物网结构错综复杂,通过观察和解剖等传统手段往往很难精准地获得物种种类及彼此之间食物关系的全面信息。近年来,DNA分子检测技术快速发展,显著促进了节肢动物食物网复杂结构的系统解析,有效实现了食物网结构分析由定性向定量的重要转变。该文介绍DNA分子检测的主要技术及其优缺点,列举其在节肢动物食物网结构分析中的应用实例,讨论DNA分子检测技术在应用中遇到的问题及挑战,旨在为节肢动物食物网结构分析提供科学依据和技术指导,有力推进农田等不同生态系统中节肢动物食物网结构及其生态功能的深入研究和挖掘利用。     

Genotypic diversity of soybean in mixed cropping can affect the populations of insect pests and their natural enemies

In order to determine the potential benefits of soybean genotypic diversity for the population densities of major insect pests and their natural enemies, the field treatments were compared in monocultures and mixed cropping systems that included five soybean cultivars. The results indicate that monocultures tended to have similar density of aphids, Aphid glycines Matsumura, but a higher density of leafhoppers, Empoasca flavescens (Fab.), than mixed cropping systems. The mixed cropping array significantly increased the population density of some generalist natural enemies, including ladybeetles, lacewings and hoverflies, to varying degrees. These findings suggest that mixed cropping systems may be more effective to control insect pests than monocultures in soybean fields, and these findings offer a practical implication in modern soybean agricultural industry.     

Detection of resistance to acetolactate synthase inhibitors in weeds with emphasis on DNA-based techniques: a review

Resistance to herbicides inhibiting acetolactate synthase (ALS) has been increasing at a faster rate than in any other herbicide group. The great majority of these cases are due to various single-nucleotide polymorphisms in the ALS gene endowing target site resistance. Many diagnostic techniques have been devised in order to confirm resistance and help producers to adopt the best management strategies. Recent advances in DNA technologies coupled with the knowledge of sequence information have allowed the development of accurate and rapid diagnostic tests. While whole plant-based diagnostic techniques such as seedling bioassays or enzyme-based in vitro bioassays provide accurate results, they tend to be labour- and/or space-intensive and will only respond to the particular herbicides tested, making resolution of cross-resistance patterns more difficult. Successful DNA-based diagnosis of ALS inhibitor resistance has been achieved with three main techniques, (1) restriction fragment length polymorphism, (2) polymerase chain reaction amplification of specific alleles and (3) denaturing high-performance liquid chromatography. All DNA-based techniques are relatively rapid and provide clear identification of the mutations causing resistance. Resistance based on non-target mechanisms is not identified by these DNA-based methods; however, given the prevalence of target site-based ALS inhibitor resistance, this is a minor inconvenience.