转抗虫基因植物对节肢动物种群和群落的影响

近年来转抗虫基因技术迅猛发展,转抗虫基因植物环境释放的安全性问题越来越成为人们关注的焦点。综述了目前转抗虫基因植物对靶标害虫、非靶标昆虫及节肢动物群落安全性的研究进展,以期为转基因植物生物安全性的研究提供科学依据。     

转基因林木生态安全性评价研究现状

近年来林木基因工程育种技术日益成熟,而转基因林木生态安全性评价相对滞后,其中转基因林木基因漂移研究尚处于空白。花粉传播是转基因植物外源基因发生转移的主要途径。文章对转基因植物基因漂移、林木开花散粉规律的研究现状进行综述,讨论了目前转基因植物基因漂移研究中存在的问题和发展前景,以期为转基因林木生态安全性评价研究提供依据。     

抗生素在农杆菌介导植物转基因中的应用

农杆菌介导植物转基因中常用抗生素包括抑茵剂和选择剂两大类。两类抗生素的作用机理不同。抗生素通常抑制植株的再生，也有较多的研究结果证明抗生素促进外植体的生长与分化。除用于筛选转化体或筛选转基因成株外，选择剂还用于鉴定转基因植物种子纯度、对转基因植物后代进行遗传分析。重点综述了农杆菌介导植物转基因中常用抗生素的作用机理及选择剂应用范围与方法的新进展，并讨论了抗生素在植物转基因中的安全性问题及应用前景。     

杨树抗虫转基因研究进展

本文对杨树抗虫基因及其杀虫机理、导入方法、检测方法、国内杨树抗虫转基因研究状况及抗虫效果、对其它生物的影响、存在的安全问题进行了系统的综述。同时,针对转基因植物生态安全性问题提出了相关对策。     

植物转基因研究进展

经对植物转基因研究的成果进行了初步分析，概述了目前转基因植株的实际应用，新性状的获得及植物转基因的常用方法，指出了当前研究中存在的一些问题，探讨了植物转基因研究未来的发展方向。     

转基因植物与转基因技术的发展与未来

进入21世纪转基因技术及其发展状况备受世人的瞩目，本文就转基因植物的产生，转基因植物的推广应用现状，世界各国对转基因研究的态度以及转基因技术的发展与未来作了较为全面的介绍与论述。     

植物转基因研究进展

经对植物转基因研究的成果进行了初步分析。概述了目前转基因植株的实际应用、新性状的获得及植物转基因的常用方法 ,指出了当前研究中存在的一些问题 ,探讨了植物转基因研究未来的发展方向     

转基因银腺杂种杨对土壤微生物的影响

近20年来,转基因林木已开始进行田间试验,其中部分还获得商品化许可.与此同时,转基因林木的生态安全问题也逐渐受到关注,但这方面研究报道还很少.目前,已开展的转基因林木安全性研究多集中在转抗虫Bt毒蛋白基因和蛋白酶抑制剂基因林木上(高素红等,2005),而很少涉及抗逆境等其他性状基因. 土壤是生态系统中物质循环和能量转化的重要场所,转基因植物体内外源基因的表达产物有可能通过植物残留物及根系分泌物对土壤生态系统特别是对土壤微生物造成影响.评价转基因林木对土壤微生物的影响也具有重要的生态学意义(胡建军等,2004).     

分子生物学在害虫生物防治中的应用研究进展

本文综述了分子生物学在抗虫基因克隆、抗虫基因工程微生物、抗虫转基因植物和转基因昆虫构建等方面的研究进展，并对其应用前景、发展趋势及存在的问题进行了讨论。     

植物抗虫基因的研究进展

随着转基因植物商品化进程的不断加深 ,转基因植物的发展前景及潜在的问题也越来越引起人们的关注 ,现对植物抗虫基因工程研究的最新进展、存在的问题及对策进行介绍     

Transgenic poplar characterized by ectopic expression of a pine cytosolic glutamine synthetase gene exhibits enhanced tolerance to water stress

Physiological responses to water stress in hybrid poplar (INRA 7171-B4, Populus tremula L. x P. alba L.) lines transformed to overexpress a pine cytosolic glutamine synthetase (GS1) gene were compared with those of non-transgenic plants. Before, during and after a drought treatment, net photosynthetic rates (Anet) were higher in transgenic than in non-transgenic plants. Stomatal conductance (gs) was higher in transgenic than in non-transgenic plants before, but not after exposure to drought. Before drought treatment, a sudden reduction in photosynthetic photon flux caused a greater burst of CO2 efflux in transgenic than non-transgenic plants, indicating greater photorespiratory activity. Drought caused greater reductions in photochemical quenching, photosystem II (PSII) antennae transfer efficiency (Fv'/Fm') and light-adapted PSII yield (PhiPSII) in non-transgenic than in transgenic plants, especially at low irradiances. Antennae-based thermal dissipation was higher in transgenic plants than in non-transgenic plants both during the imposition of drought and 1 or 3 days after the relief of drought. Under severe water stress and subsequently, transgenic plants maintained a higher expression of glutamine synthetase, glutamate synthase and Rubisco and higher concentrations of chlorophyll and glycine than non-transgenic plants. These findings indicate that overexpression of pine cytosolic GS1 enhanced sustained photosynthetic electron transport capacity during severe stomatal limitation. The data also suggest that ectopic expression of cytosolic GS increases photorespiratory activity, and that this serves as a protective sink for electrons from photosynthetic reaction centers.     

TERF1基因增强糖橙抗病性的初步研究

将获得转TERF1基因糖橙的春梢叶片进行柑桔溃疡病和炭疽病的接种.初步试验表明,TERF1基因增强了糖橙的广谱抗病性.在接种溃疡病后,转基因植株的平均发病率下降了50%左右,且发病的时间比冰糖橙和对照推迟了7 d,其中3号株系的抗病性最强,叶片无病症.柑橘叶片接种炭疽病后,转基因植株的叶片与对照相比基本上表现出针孔处病斑减小,延迟发病等现象.其中3号和11号转TERF1基因糖橙叶片上根本观察不到炭疽病的典型病斑,且叶片也无褪绿.     

Antisense expression of a caffeic acidO-methyltransferase ofStylosanthes humilis in transgenic poplar: Effect of expression onO-methyltransferase activity and lignin composition

Poplar (Populus tremula) was transformed with a construct carrying an antisense caffeic acidO-methyltransferase (COMT) cDNA (pOMT8) from a tropical pasture legume,Stylosanthes humilis. pOMT8 shows 83% overall homology to the corresponding COMT gene (pPCLA) of poplar. Of the 200 putatively-transformed plants regenerated on selective media after co-cultivation of poplar stem explants withAgrobacterium tumefaciens harbouring a CaMV 35S-antisensepOMT8 construct, a subset of 20 plants were randomly chosen for further analysis. PCR and Southern blot analysis demonstrated the stable integration of T-DNA into the genome of these plants. Antisense expression ofpOMT8 resulted in reductions in total COMT activity in the majority of the transgenic plants with the lowest total COMT activities (61–70% of untransformed control plants) being observed in four transgenic plants. The composition of lignin in transgenic plants was also changed, as detected by reductions in the content of syringyl units using infrared spectroscopy. However, no changes were found in the amount of insoluble lignin in transgenic plants as compared to untransformed control plants. These results indicate the potential of thepOMT8 gene to partially suppress COMT activity and modify the composition of lignin in transgenic poplar. This work was partly supported by General Management of Turkish Pulp and Paper Mills.     

转抗虫基因三倍体毛白杨成年树木节肢动物及抗虫稳定性调查

对田间生长的8 a生转抗虫基因（Bt cry1A和API）三倍体毛白杨进行分子生物学检测,证明外源基因在杨树基因组中稳定存在。对试验林进行节肢动物调查表明,林内节肢动物共有11个目、26个科,已明确为害虫的有11种,占整个群落的42%;天敌（包括捕食性与寄生性）8种,占群落的31%;中性昆虫7种,占群落的27%,其中主要害虫为美国白蛾。秋季对试验林叶面积损失调查表明,不同转基因系号的抗虫性有明显差异,有4个株系没有被美国白蛾啃食,10个株系的食叶面积小于10%,6个株系的食叶面积在10%~15%之间。     

我国林木抗虫性及其利用的研究

对我国常规树种和转抗虫基因树种在抗虫性及其利用方面的主要研究与实践成果进行了综述,从系统科学的角度,提出了林木抗虫性的概念,指出了林木抗虫性的作用特点和利用原则。     

Overexpression of mtlD gene in transgenic Populus tomentosa improves salt tolerance through accumulation of mannitol

The mtlD gene encoding mannitol-1-phosphate dehydrogenase, which catalyzes the biosynthesis of mannitol from fructose, was cloned from Escherichia coli and transferred to poplar (Populus tomentosa Carr.) through Agrobacterium-mediated transformation. The transgenic plants were screened and selected on Murashige and Skoog (MS) medium containing 30-50 mg l(-1) kanamycin and verified by polymerase chain reaction (PCR) and Southern blotting. Expression of the gene led to synthesis and accumulation of mannitol in the transgenic plants. Gas chromatography and mass spectrometry (GC/MS) and capillary gas chromatography (GC) showed that transgenic plants accumulated much more mannitol in their tissues than the wild-type plants, whether cultured in vitro, or grown hydroponically or in the field. Increased salt tolerance of transgenic plants was observed both in vitro and in hydroponic culture. The transgenic buds rooted normally on MS medium containing 50 mM NaCl, whereas wild-type buds did not. In the 40-day hydroponic experiments, transgenic poplar plants survived in a 75-mM NaCl treatment, whereas the wild-type poplar plants tolerated only 25 mM NaCl. Under the same NaCl stress, stomatal conductance, transpiration rates and photosynthetic rates were all higher in transgenic plants than in wild-type plants, whereas cellular relative conductivity was lower. We demonstrated that the mtlD gene was expressed in transgenic poplar plants, resulting either directly or indirectly in mannitol accumulation and improved salt tolerance. The constant mannitol concentrations in transgenic plants during the NaCl treatments indicated that mannitol accumulation caused by the mtlD gene was not a consequence of NaCl stress. Height growth was reduced by about 50% in the transgenic plants compared with the wild-type plants in the absence of salt; however, relative growth rate was much less influenced by salt stress in transgenic plants than in wild-type plants. The stunted growth of the transgenic plants may in part explain their improved salt tolerance.     

过量表达LAR3和Bbchit1以提高毛白杨对叶枯病的抗性

利用转基因技术将多种抗病基因共同转入毛白杨中以提高其抗性,从而获得毛白杨抗病新品种是目前解决杨树真菌病害的主要研究方向之一。本研究通过根癌农杆菌介导的二次遗传转化,将来源于球孢白僵菌几丁质酶基因Bbchit1转入过量表达无色花色素还原酶基因LAR3转基因毛白杨中,实时定量PCR显示Bbchit1与LAR3均能有效表达,离体抗病试验显示Bbchit1+LAR3共表达转基因毛白杨细胞粗提液对杨树叶枯病菌具有明显抑制作用,进一步将叶枯病菌接种在转基因和非转基因毛白杨叶片上培养30天,转基因植株的感病面积均低于非转基因植株且Bbchit1+LAR3共表达转基因株系抗病效果更明显。上述抗病试验结果表明:LAR3和Bbchit1在杨树中共表达可提高其对叶枯病的抗性。     

多拷贝rol基因对转基因杨树生长及内源激素的影响

对转入多拷贝rolB、rolC基因的三倍体毛白杨进行高生长量、生根率和内源激素(IAA、ABA)含量等指标的测定,以研究多拷贝rol基因在转基因植物中的表达。结果显示:转Ri质粒三倍体毛白杨再次分别转入rolB、rolC基因后,部分株系试管苗的生长受到了抑制,但各株系生根率均有不同程度提高;rolB基因转化植株的内源IAA平均含量高于rolC基因转化植株,其IAA/ABA值亦高于rolC基因转化植株。试验结果表明rol基因的多拷贝促使转化植株快速大量生成毛状根。     

抗虫转基因杨树的培育及其抗虫性初步研究

以杨树优良新品种欧美杨107(Populus×euramericanacl."74/76")为试材,通过根癌农杆菌(Agrobacteriumtumefaciens)介导法,将Bt毒蛋白基因导入107杨的叶片及茎段外植体,经潮霉素抗性筛选,获得了转基因再生植株。提取转基因植株的总DNA,经PCR扩增,部分植株呈阳性反应,证明目的基因已经整合到杨树基因组中。以转基因杨树叶片饲喂天幕毛虫幼虫的杀虫试验结果表明,转基因杨树表现出一定的杀虫活性。