Taqman定量PCR技术检测转基因大豆中外源基因拷贝数

[目的]采用Taqman定量PCR技术检测转基因杂交大豆中外源nos终止子基因的拷贝数。[方法]以大豆凝集素基因为内参照基因,以非转基因大豆基因组DNA为内参照基因标准品,通过梯度稀释法分别求取了内参照基因和质粒DNA的Ct值与拷贝数对数值的相关性标准曲线方程,并通过将得到的Ct值代入标准曲线方程求取了样品的拷贝数。[结果]内参照基因标准曲线方程为y=-3.422x＋35.201,R2=0.998;外源基因标准曲线方程为y=-3.348x＋34.890,R2=0.999。nos终止子基因及其下游边界序列在转基因杂交大豆中为单拷贝。[结论]该研究为确定转基因大豆外源基因拷贝数提供了理论依据。     

Taqman定量PCR技术检测转基因大豆中外源基因拷贝数

[目的]采用Taqman定量PCR技术检测转基因杂交大豆中外源,Ⅲ终止子基因的拷贝数。[方法]以大豆凝集素基因为内参照基因,以非转基因大豆基因组DNA为内参照基因标准品,通过梯度稀释法分别求取了内参照基因和质粒DNA的cz值与拷贝数对数值的相关性标准曲线方程,并通过将得到的0值代入标准曲线方程求取了样品的拷贝数。[结果]内参照基因标准曲线方程为Y=-3．422x＋35．201,R^2=O．998;外源基因标准曲线方程为Y=-3．348x＋34．890,R^2=0．999。nos终止子基因及其下游边界序列在转基因杂交大豆中为单拷贝。[结论]为确定转基因大豆外源基因拷贝数提供了理论依据。     

TaqMan定量PCR检测水稻中外源基因含量

[目的]采用TaqMan定量PCR技术检测水稻中外源基因含量。[方法]采用TaqMan定量PCR技术以编码磷脂酶D基因PLD为内标准基因,检测转基因水稻中外源TT51-1的含量。利用DNA梯度稀释法分别求内标准基因PLD和TT51-1的C_t值与拷贝数对数值的标准曲线方程,并将得到的C_t值代入标准曲线方程求取样品中外源基因的拷贝数。[结果]内标准基因PLD标准曲线方程为y=-3.403x+39.939,R~2=0.993;TT51-1基因标准曲线方程为y=-3.35x+37.37,R~2=0.991,转基因含量为1.21%,不确定度为0.45。[结论]TaqMan定量PCR技术可以用于确定转基因作物外源基因含量。     

马铃薯T-DNA插入拷贝数的检测及对农艺性状的影响研究

以转基因马铃薯株系为材料,采用Real-time PCR方法,以SYBR Green I为荧光染料,以马铃薯块茎贮藏蛋白基因(Patatin)作为内参基因,以植物表达载体上的潮霉素抗性基因(HPT)为筛选标记基因,建立目的基因CT值与起始模版的相关性标准曲线,通过实时荧光定量PCR分别获得每个样品中内参基因和外源基因的CT值,根据Pfaffl法计算获得了T-DNA在转基因马铃薯中的拷贝数,且与Southern blot方法进行了比较,并结合田间农艺性状,分析了外源基因拷贝数马铃薯株高及薯块产量的影响。结果表明,内参基因和外源基因标准曲线的相关系数分别为R2=0.996、R2=0.995和R2=0.990。在所测的23株转基因株系中,12株为单拷贝插入,6株为双拷贝,5株为多拷贝。Real-time PCR比Southern blot方法结果更准确、操作更简便快捷、成本更低。且插入拷贝数的多少与马铃薯田间农艺性状变化有一定的关系,发现2拷贝以上的T-DNA插入较容易引起部分性状的改变。     

过表达酵母PAC1增强转基因大豆对大豆花叶病毒的抗性

【目的】大豆花叶病毒（soybean mosaic virus,SMV)病是中国大豆产区最主要的病害之一,严重影响大豆产量和籽粒品质。核糖核酸酶PAC1能够识别和降解植物RNA病毒或类病毒复制过程中产生的dsRNAs,从而有效抑制病毒在寄主中的复制与积累。PAC1的这一特点为广谱抗RNA病毒及类病毒转基因作物的创制和培育提供了有效的靶标基因。本研究利用转基因技术,将来源于粟酒裂殖酵母菌(Schizosaccharomyces pombe)的PAC1导入栽培大豆,研究过表达PAC1对大豆SMV抗性的影响,为抗SMV转基因大豆新品种选育提供依据。【方法】采用酶切连接技术,将PAC1连接到双元表达载体pCAMBIA3300中,构建植物表达载体pCAMBIA3300-PAC1。目的基因启动子为组成型强启动子CaMV 35S,终止子为NOS,筛选标记为草铵膦抗性基因BAR。采用农杆菌介导转化法,将PAC1导入栽培大豆品种Williams82。在利用PAT/BAR试纸、PCR及除草剂（500 mg·L^-1 Basta）喷施检测基础上,通过Southern杂交技术进一步分析外源基因在转基因大豆中的整合情况和拷贝数。采用人工摩擦接种法,对T₂和T₃代转基因大豆株系进行田间抗SMV鉴定农艺性状调查,分析转基因大豆对SMV抗性及遗传稳定性。并利用qRT-PCR技术分析接种SMV 28 d后转基因大豆中SMV积累水平。【结果】共转化2 600多个外植体,获得耐草铵膦（5 mg·L^-1）大豆再生植株76株。PCR检测结果表明,其中65株能够扩增出目的条带,大豆遗传转化效率为2.48%。对T₁-T₃代转基因大豆株系喷施除草剂表明,在500 mg·L^-1 Basta处理7 d后,转基因植株表型没有明显变化,而对照（非转基因大豆）植株叶片则黄化枯死。Southern杂交结果表明,外源基因以低拷贝的方式(1-2个)整合至大豆基因组中。摩擦接种SMV SC-3鉴定表明,在接种35 d后,对照出现严重花叶、皱缩等典型SMV发病症状,而转基因大豆仅部分叶片表现出轻微的花叶症状,其病情指数降低至11.11-22.22,较对照（病情指数36.81-46.24）显著降低,且SMV抗性在转基因大豆不同代际间能够稳定遗传。qRT-PCR分析表明,在接种SMV SC-3株系28 d后,转基因大豆中SMV CP表达水平较对照极显著下降。农艺性状调查表明,在未接种SMV条件下,转基因大豆在叶形、花色、种皮色、种脐色、株高、节数、结荚高度、生育期及百粒重等方面与对照没有显著差异。【结论】PAC1过表达显著抑制了SMV的积累及症状发展,增强了转基因大豆对SMV的抗性水平。     

抗草甘膦转基因大豆PCR定量检测研究

试验建立大豆中转基因成分的定量测定方法。采用双链DNA SYBR Green I结合染料实时荧光定量PCR技术，扩增编码大豆凝集素的内参照基因lec和抗草甘膦转基因大豆中的外源花椰菜花叶病毒CaMV35s基因。绘制2种基因扩增的循环数一拷贝数标准曲线图，根据标准曲线方程计算样品中的转基因含量；并作重现性和熔解曲线分析。结果表明，lec和CaMV35s基因标准曲线方程线性好，R^2值分别达到0．9997和0．9992。不同转基因含量的标准及模拟大豆样品定量显示，实测值与实际值接近，相对偏差5％～11％。SYBR Green I实时定量PCR方法可用于定量测定大豆中转基因品种的含量。     

SYBR Green实时定量PCR检测转基因大豆中外源基因拷贝数

采用SYBR Green I real-time PCR方法检测转基因大豆中外源基因35S边界基因的拷贝数,以大豆凝集素基因(Lectin)作为内参照基因,以转基因大豆基因组DNA为内参照基因标准品,初始浓度为0.43μg·μL-1,进行5倍梯度稀释得到内参照基因CT值与起始模板量的相关性标准曲线:y=-2.9915x...     

禽呼肠孤病毒σ3基因在烟草中的表达与鉴定

【目的】研究禽呼肠孤病毒S1基因编码的σ3基因在烟草中的表达及其表达产物的反应原性。【方法】根据Gen Bank中公布的禽呼肠孤毒株S1133的基因序列,设计特异引物扩增σ3基因,构建重组植物表达载体p BI121-σ3,热激法转化农杆菌EHA105感受态细胞,筛选含有重组质粒的p BI121-σ3的阳性工程菌株EHA105。采用农杆菌介导的叶盘法转化野生型烟草,卡那霉素筛选获得抗性植株。随后通过σ3基因的特异引物,PCR方法初步筛选获得转σ3基因的烟草植株。进一步对阳性植株通过实时荧光定量PCR方法检测σ3基因在转基因烟草中的拷贝数,以烟草自身单拷贝的内源基因核糖核酸还原酶-RNR2作为内参基因,通过梯度稀释分别构建RNR2及σ3基因的起始模板量和对应CT值的标准曲线,通过检测样品中σ3基因和RNR2基因模板量对数值的比值估算出σ3基因在转基因烟草中的拷贝数。并通过Western-blotting方法对转基因烟草中表达的σ3融合蛋白的反应原性进行分析。【结果】1通过双酶切和测序验证表明σ3基因插入位置、大小和读码框均正确,表明σ3基因已经成功的构建于植物表达载体p BI121的花椰菜花叶病毒(Ca MV)35S启动子的下游,以NOS为终止子,含有卡那霉素抗性标记(NPT II)。其表达的蛋白与下游的绿色荧光蛋白形成融合蛋白,其大小约为61.6 ku;2在转化筛选抗性植株的过程中采用350 mg·L-1的头孢霉素可以很好地抑制农杆菌的污染,100 mg·L-1的硫酸卡那霉素筛选压力能够很好地抑制非转化细胞的生长;3随机选取10株转化烟草进行PCR检测发现8株转化烟草可以扩增到清晰的目的条带约994 bp;4内参基因RNR2的标准曲线为y=-3.5352x+15.143,σ3基因的标准曲线为y=-3.5366x+1.8265,两个标准曲线的相关系数均接近于1。在检测的5株转化烟草中σ3基因的拷贝数均为4,阴性对照没有扩增。5Western-blotting显示σ3融合蛋白在转化烟草中可以正确表达,目的条带大小约为61.6 k D,与预计大小一致;σ3融合蛋白能够与禽呼肠孤病毒的阳性血清发生特异反应,表明该融合蛋白具有良好的反应原性。【结论】成功地构建了植物表达载体p BI121-σ3,筛选获得低拷贝的转σ3基因的烟草,σ3融合蛋白能够在烟草中表达且具有相应的反应原性,为进一步研究σ3基因的功能和利用植物作为生物反应器生产σ3蛋白口服疫苗的研发奠定了基础。     

转基因小麦B73-6-1外源基因拷贝数的确定

为了确定转基因小麦B73-6-1中外源基因HMW-GS的拷贝数,以期为HMW-GS基因的整合位点和遗传表达研究奠定基础,构建了含有外源基因HMW-GS的标准品,并以wx012基因作为内源参照,通过实时荧光定量PCR方法,进行了3次重复试验。结果表明,在3组试验中得到的HMW-GS基因分子数分别为8.62×1018、4.34×1018、1.10×1018个,wx012基因分子数分别为6.27×1017、3.14×1017、7.84×1017个,经计算HMW-GS基因拷贝数分别为13.75、13.84、14.01个,由此确定转基因小麦B73-6-1中HMW-GS外源基因的拷贝数为14个。     

转TaNHX2大豆的耐盐性分析

【目的】在盐胁迫条件下,通过对转TaNHX2(小麦Na⁺/H⁺转运蛋白编码基因)大豆的盐害表型、光合作用强度以及产量相关农艺性状的考察,评估其生产应用潜力,以期获得具有一定应用价值的耐盐大豆新种质。【方法】以实验室前期获得并初步鉴定具有一定耐盐性的转TaNHX2大豆T₄代株系为材料,在主茎第二片复叶完全展开时（V₃期）进行草丁膦抗性、PCR和RT-PCR检测。选取阳性植株,在主茎第三片复叶完全展开时（V₄期）进行NaCl胁迫处理,处理期间观察记录盐害表型;待植株长至初荚期（R₃期）测定其光合作用参数;最后,分单株收获已生长至完熟期（R₈期）的大豆植株,考察其株高、节数、单株荚数、单株粒数和单株粒重。其中,昌平春播试验点设置0、150和200 mmol·L^-1 3个NaCl浓度,北圃场夏播试验点设置0和200 mmol·L^-1 2个NaCl浓度,盐害表型观察以及光合作用参数测定只在北圃场试验点进行。【结果】分子鉴定表明外源TaNHX2在转基因后代中成功转录表达,遗传稳定。在无盐胁迫条件下,转基因与受体植株长势相当,叶片大小相似,光合作用强度相近。而在200 mmol·L^-1 NaCl溶液胁迫处理下,转基因与受体植株均出现矮化、叶片变小、光合作用强度降低的现象,但与受体植株相比,转基因大豆株系C12、C21和C19的矮化程度较低,叶片较大,光合作用相关参数数值较大,其中株系C12和C21与受体的净光合速率（Pn）差异具有显著性。另外,无盐胁迫条件下,转基因株系与受体品种自贡冬豆各产量相关农艺性状数值相近,而在昌平试验点设置的150和200 mmol·L^-1 NaCl溶液胁迫下,转基因株系各农艺性状数值均高于受体对照,其中150 mmol·L^-1 NaCl胁迫下,C12、C21和C19的单株粒重,C19的单株荚数与受体差异显著。200 mmol·L^-1 NaCl胁迫处理时,株系C12、C21和C19的单株荚数、单株粒数和单株粒重,C12和C19的株高均与受体对照品种存在显著性差异。在北圃场试验点设置的200 mmol·L^-1 NaCl胁迫处理下,转基因株系C12、C21和C19的株高、C19的单株粒数和单株粒重与受体对照品种具有显著性差异。【结论】在盐胁迫条件下,与受体对照品种相比,转TaNHX2大豆株系C12、C21和C19盐害程度较低,能维持较强的光合作用和一定的产量,其中株系C19在2个试验点的产量表现均较佳,具有较大的育种应用价值。      

Comparison of Two Real-time PCR Technigues for Quantification of GMO Contents in Highly Processed Products of Soybean

The RR soybean was quantitatively detected by ABI Prism 7300 sequence detector with PCR primers and fluorescence probes were designed according to the sequences of endogenous Lectin gene and exogenous CP4-EPSPS gene, and the PCR systems were based on SYBR GreenΙand TaqMan. The standard curve of °Ct between CP4-EPSPS gene and Lectin gene of the RR soybean in standard materials was generated and a linear regression equation was obtained. Quantification methods were optimized through two different real-time PCR chemistries, i.e. SYBR GreenΙand TaqMan, and the RR soybean contents were quantified in five standard samples and seven highly processed products by the two assays. Both methods are proved to be specific, highly sensitive and reliable for both identification and quantification of soybean DNA. The results indicate that the two optimized PCR system can be used for the practical quantitative detection of RR soybean in highly processed products.     

豆粕中转基因成分检测方法的研究

从核酸和蛋白质两个角度对转基因豆粕及大豆原料进行了检测方法上的研究。设计并合成引物对转基因豆粕的内源基因lectin、CaMV35S启动子基因、NOS终止子和Cp4-epsps基因进行检测。应用ELISA的方法对不同含量的转基因蛋白及转基因豆粕进行检测,其检测的灵敏度可达到0.25%,但ELISA不适用于加工产品转基因成分的检测。Western杂交检测转基因豆粕及大豆,其检测极限达到0.5%。对于豆粕这样的加工产品,检测蛋白质及核酸两种方法结合使用,可使检测结果更为准确。     

转基因水稻深加工产品两种荧光定量方法的比较研究

根据转基因水稻中外源基因Cry1A(B)和内源基因SPS设计SYBR Green I引物、TaqMan引物和荧光探针,以内源基因SPS作为内参照,使用两种FQ-PCR方法对水稻深加工产品中转基因水稻的含量进行定量检测.建立了转基因水稻标准品Cry1A(B)和SPS之间的△Ct与样品中转基因水稻含量百分比之间的校正曲线和...     

Overexpression of G10-EPSPS in soybean provides high glyphosate tolerance

Glyphosate is a highly efficient, broad-spectrum nonspecific herbicide that inhibits the 5-enolpyruvylshikimate-3-phosphate synthase(EPSPS)-mediated pathway of shikimic acid. The screening of glyphosate-resistant EPSPS gene is a major means for the development of new genetically modified glyphosate-resistant transgenic crop. Currently, the main commercialized glyphosate-resistant soybean contains glyphosate-resistant gene CP4-EPSPS. In this study, a G10-EPSPS gene was reported providing glyphosate resistance in Zhongdou 32. Here, G10-EPSPS gene was introduced into soybeans through Agrobacterium-mediated soybean cotyledon node. PCR, Southern blotting, semi-quantitative RT-PCR, qRT-PCR, and Western blotting were used, and the results revealed that G10-EPSPS had been integrated into the soybean genome and could be expressed steadily at both mRNA and protein levels. In addition, glyphosate resistance analysis showed that the growth of transgenic soybean had not been affected by concentrations of 900 and 2 700 g a.e. ha~(–1) of glyphosate. All the results indicated that G10-EPSPS could provide high glyphosate resistance in soybeans and be applied in production of glyphosate-resistant soybean.     

Development and identification of glyphosate-tolerant transgenic soybean via direct selection with glyphosate

Glyphosate-tolerant soybean is the most widely planted genetically modified crop worldwide. However, soybean remains recalcitrant to routine transformation because of the low infection efficiency of Agrobacterium to soybean and lack of useful selectable markers. In this study, several Agrobacterium strains and cell densities were compared by transient expression of the GUS gene. The results showed that Agrobacterium strain Ag10 at cell densities of OD_(600) of 0.6–0.9 yielded the highest infection efficiency in Agrobacterium-mediated soybean cotyledonary node transformation system. Meanwhile, a simple and rapid method was developed for identification of glyphosate tolerance in putative T_0 transgenic plants, consisting of spotting plantlets with 1 μL Roundup~?. The whole cycle of genetic transformation could be shortened to about 3 mon by highly efficient selection with glyphosate during the transformation process and application of the spot assay in putative T_0 transgenic plantlets. The transformation frequency ranged from 2.9 to 5.6%. This study provides an improved protocol for development and identification of glyphosate-tolerant transgenic soybeans.     

转基因大豆研究及应用进展

转基因技术是一种以分子生物学技术为核心,对基因进行修饰、改造,从而定向改变生物体遗传性状的技术。基于转基因技术在大豆中的应用,从技术研发手段、外源基因挖掘、转基因大豆品种、大豆除草剂、种植面积、研发体系等方面对国内外转基因大豆研究及应用进展进行概述,以期为发展中国大豆转基因技术提供借鉴和参考。分析指出,国外转基因大豆研发能力较为成熟,大豆外源基因转化技术主要采用农杆菌介导转化法和微弹轰击法,通过cp4、dmo、Pat、cry1Ac、fatb1-A等目的基因的表达,得到抗虫、抗除草剂、高油酸以及具复合性状的大豆品种,同时转基因产权保护体系比较健全,促进转基因大豆的产业化;而中国转基因大豆研究多为基础性研究,侧重于基因检测和再生体系培育,外源基因转化技术缺乏创新性,存在转基因安全性结论未定、舆论环境尴尬、研发体系不完善、审批过程复杂、具有完全自主知识产权的基因开发数量少,高油、抗生素抗性等功能性基因挖掘不足等问题,制约中国转基因大豆产业化进程。今后应改革高校和科研机构考核制度、强化产学研模式、完善转基因产权保护机制、加强转基因科普与监管,为转基因技术及其产业化营造更加健康的发展环境。     

Evaluation of a new qPCR test to identify the organisms causing high total bacterial count in bulk tank milk

Milk quality in bulk tank milk(BTM)is measured by flow cytometry technology as total bacterial count(TBC)and somatic cell count(SCC).To investigate SCC problems,culture or PCR can be used to identify mastitis causing bacteria,e.g.,Mastit 4,a commercially available qPCR test.TBC in BTM can be investigated further using culture-based methods such as standard plate count,laboratory pasteurization count,coliform count,and spore counts.To our knowledge,no qPCR addressing the bacteria involved in TBC has been commercially introduced.The aim of this study is to evaluate a recently introduced 3-h qPCR test,TBC 4.The TBC 4 qPCR detects four target groups,Pseudomonas,Streptococci,Enterobacteriacea/Enterococcus,and Bacillus/Clostridia.These target groups relate to problems on the farm such as cooling,mastitis,environment,and silage.We will continue with new research to compare the TBC 4 qPCR test with traditional culture.For this study,BTM samples from different TBC intervals were selected based on Bacto Count results found at routine payment investigation at Eurofins laboratory(Vejen,Denmark).These samples were analyzed using TBC 4 qPCR assay within 24 h.In total,346 BTM samples were divided into six different intervals of colony forming units(CFU).For all four targets in each of the different intervals of CFU,the percent of positive samples,the average C_t-value,the percent of positive samples with C_t30 and C_t25 were calculated.For Pseudomonas,Streptococci,and Enterobacteriacea/Enterococcus,the number of positive samples with lower C_t-values(high bacteria content)correlated with the CFU mL~(–1).We found Enterobacteriacea/Enterococcus,Pseudomonas,and Streptococci in high number of bacteria(C_t25)in 25,19 and 56%of samples with CFU mL~(–1) between 50 001–100 000 and 53,44,and 39%in samples with CFU mL~(–1)100 000.The TBC 4 qPCR test showed to be a strong and fast tool for farmers,advisors and service technicians to address problems with high TBC and ensuring the delivery of good quality milk to the dairy.     

转基因玉米的定性PCR检测

根据玉米内参照基因zSSIIb和转基因玉米中常见的CaMV35S、NOS、Bt、hpt等基因的特异性结构,设计5对定性PCR引物,经定性PCR检测,可以准确地将转基因玉米的目的基因检出,说明这5对引物具有较高的特异性和准确性。由此建立了一套转基因玉米定性PCR检测方法,用于转基因玉米及其产品的筛查、抽检。     

Overexpression of GmBIN2, a soybean glycogen synthase kinase 3 gene,enhances tolerance to salt and drought in transgenic Arabidopsis and soybean hairy roots

Glycogen synthase kinase 3 (GSK3) is a kind of serine/threonine kinase widely found in eukaryotes. Many plant GSK3 kinases play important roles in regulating stress responses. This study investigated BRASSINOSTEROID-INSENSITIVE 2 (GmBIN2) gene, a member of the GSK3 protein kinase family in soybean and an orthologue of Arabidopsis BIN2/AtSK21. GmBIN2 expression was increased by salt and drought stresses, but was not significantly affected by the ABA treatment. To examine the function of GmBIN2, transgenic Arabidopsis and transgenic soybean hairy roots were generated. Overexpression of GmBIN2 in Arabidopsis resulted in increased germination rate and root length compared with wild-type plants under salt and mannitol treatments. Overexpression of GmBIN2 increased cellular Ca²⁺ content and reduced Na+ content, enhancing salt tolerance in transgenic Arabidopsis plants. In the soybean hairy root assay, overexpression of GmBIN2 in transgenic roots also showed significantly higher relative root growth rate than the control when subjected to salt and mannitol treatments. Measurement of physiological indicators, including proline content, superoxide dismutase (SOD) activity, and relative electrical conductivity, supported this conclusion. Furthermore, we also found that GmBIN2 could up-regulate the expression of some stress-related genes in transgenic Arabidopsis and soybean hairy roots. Overall, these results indicated that GmBIN2 improved tolerance to salt and drought in transgenic Arabidopsis and soybean hairy roots.     

转基因番茄定性PCR检测

根据番茄内参基因PG和转基因番茄中常见的CaMV 35S启动子、NOS终止子、npt-Ⅱ基因、反义EFE基因等的特异性结构,设计5对定性PCR引物,经定性PCR检测,可以准确地检测出目的基因,说明这5对引物具有较高的特异性和准确性,可以用于转基因番茄及其产品的定性PCR检测。