枣疯病植原体TaqMan探针实时荧光定量PCR检测方法的建立

根据枣疯病植原体16S rDNA基因保守区域设计、合成特异性引物和TaqMan探针, 以构建的重组质粒作为阳性标准品, 建立并优化了对枣疯病植原体的TaqMan实时荧光定量PCR检测方法。对优化后的方法进行灵敏度、特异性及稳定性评价, 制作了标准曲线。结果显示, 制作的标准曲线有极好的线性关系, 相关系数( r 2 )达到0.998, 建立的实时荧光定量PCR检测方法能够特异性地检测枣疯病植原体, 能检测到60拷贝的质粒DNA。本研究建立的实时荧光定量PCR检测方法灵敏度、特异性、重复性好, 不仅能够实现对枣疯病植原体的快速检测, 而且为实现从病原定量水平上对枣疯病病情分级奠定了基础。     

杜松烯合成酶作为转基因棉花PCR检测的内参照基因

根据棉属植物中棉酚合成的关键酶之一杜松烯合成酶[（＋）-d-cadinene syhnthase]基因序列，设计合成了该酶的实时荧光PCR的引物和TaqMan探针，经研究发现，此套引物探针能特异性检测海岛棉和陆地棉，有较高的检测灵敏度。同马铃薯、大椒、茄子、烟草、番茄、玉米、大豆、小麦、水稻和其它转基因作物无非特异性反应，可以作为转基因棉花检测的内参照。     

一种测定水稻白叶枯菌基因组中插入序列IS1112拷贝数的定量PCR方法

建立了以标准质粒为基础的测定水稻白叶枯基因组中插入序列IS1112拷贝数的TaqMan实时荧光定量PCR方法。通过重叠PCR方法扩增了由16S rDNA基因与插入序列IS1112的部分片段组成的重组片段,连接到载体pMD18-T上,构建了标准质粒。利用该标准质粒建立的定量方法测定了我国12种白叶枯菌株基因组中IS1112的拷贝数。     

甘蔗宿根矮化病菌实时荧光定量PCR检测方法的建立

 甘蔗宿根矮化病是由Leifsonia xyli subsp. xyli (Lxx)引起的一种世界性甘蔗细菌病害。根据Lxx的Pat1基因保守序列,设计并合成了一对特异性引物Pat1F (5′-GGTTCCATTGCTTACCGATT-3′)/Pat1R(5′-CAAGTTTCGACAGGAACAGC-3′),和一条TaqMan探针(FAM-5′-CCACGGCTACGTCAATTCGGG-3′-TAMRA),建立了一种特异性强、灵敏度高的甘蔗宿根矮化病菌实时荧光定量PCR检测方法。结果表明,本研究建立的实时荧光定量PCR方法,对Lxx的检测最低下限为10² copies·μL^-1。应用实时荧光定量PCR与常规PCR方法对14个甘蔗品种进行Lxx检测,阳性检出率分别为86%和43%,表明实时荧光定量PCR比常规PCR检测方法具有更高的灵敏度。研究结果为甘蔗宿根矮化病的诊断、田间发生动态监测、脱毒健康种苗检测及品种/材料交换检疫检测提供了新技术支撑。     

葡萄根瘤蚜TaqMan-MGB实时荧光定量检测方法的研究

为建立葡萄根瘤蚜实时荧光定量PCR的检测方法,参考Karen Herbert等设计的特异性引物与TaqMan-MGB荧光探针,构建以标准阳性质粒作为标准品制作标准曲线,并经优化反应条件,建立葡萄根瘤蚜的实时荧光PCR绝对定量检测方法,进行敏感性和重复性试验,并对受葡萄根瘤蚜为害的葡萄根际土壤进行初步定性检测.结果表明:该方法的灵敏度可达1.625拷贝/μL,3次重复检测的变异系数均小于5％.提取0.25g含有10头葡萄根瘤蚜若虫土壤的DNA,并将其梯度稀释,用建立的荧光定量PCR进行检测,将DNA稀释103倍后,仍能检测出阳性结果.对受害葡萄根际土壤检测结果为阳性.葡萄根瘤蚜TaqMan-MGB探针实时荧光PCR检测技术具有特异性强,敏感性高,易操作等优点,有很好的应用前景和研究价值.     

利用实时荧光定量PCR 技术检测油菜菌核病菌

 采用高通量实时荧光定量PCR 技术建立检测和监测油菜菌核病菌群体数量的方法。利用油菜菌核病菌(Sclerotiniasclerotiorum)的茁-微管蛋白基因内含子序列的特异性,设计引物对SclSF (5'-CTCAAATCTCCGAAAGTT -3') / SclAF (5'-TGCAGACGGGTAATATG -3'),建立和优化了SYBR Green 玉实时荧光定量PCR 检测体系。结果表明,该引物对能够从8种所测试的十字花科植物常见病原真菌中特异性扩增出油菜菌核病菌;所建立的实时定量PCR 技术可应用于油菜病叶和病茎中菌核病菌的早期检测及菌核病的预测预报。     

利用Real-time RT-PCR方法检测苹果中苹果茎沟病毒

以含有苹果茎沟病毒(Apple stem grooving virus,ASGV)的苹果枝条为试材,设计扩增产物片段为176 bp的特异性引物,优化反应条件,构建标准曲线,建立了苹果茎沟病毒的SYBR Green Ⅰ实时荧光定量RT-PCR检测方法.对该方法进行了灵敏度和重复性试验,并且利用建立的方法对受ASGV感染的苹果枝条和树叶进行定量检测.最后,比较了实时荧光定量RT-PCR与常规RT-PCR检测的灵敏度.结果表明:样品的荧光定量PCR有良好的扩增曲线和溶解曲线,该方法的灵敏度可达6.8× 102拷贝/μL,检测其灵敏度是传统RT-PCR的100倍,所建立的荧光定量技术可用于田间样品中此病毒的检测,丰富了ASGV的检测手段,提高了检测灵敏度,具有较好的应用前景.     

实时荧光定量PCR法检测十字花科细菌性黑斑病菌

为有效防控我国的检疫性有害生物十字花科细菌性黑斑病菌Pseudomonas syringae pv.maculicola在国内的传播与蔓延,通过设计1对特异性引物3539,利用132株靶标和非靶标菌为模板进行PCR扩增,建立了实时荧光定量PCR法,并进行了模拟种子带菌试验。结果显示,引物3539为只针对十字花科细菌性黑斑病菌扩增出的特异性产物;在模拟种子带菌检测中,常规PCR对菌悬液的检测限为10~5CFU/m L,实时荧光定量PCR的检测限为10~3CFU/m L,其中10~8CFU/m L菌液的Ct值最低,为22.90,10~3CFU/m L菌液的Ct值最高,为35.73,且不同浓度菌液间的Ct值均有显著差异;不同带菌率模拟种子的检测结果表明,常规PCR和实时荧光定量PCR能检测到的带菌率分别为0.5%和0.1%。研究表明,实时荧光定量PCR法不仅可用于病种的检测,也可用于病害的早期诊断。     

实时定量PCR方法检测转基因产品

实时定量PCR方法检测转基因产品，操作简单，省时省力，结果可靠、准确性高。该方法利用特异性荧光探针实时监测目的的基因的扩增，同时循环参数（Ct值）和PCR体系中起始DNA量的对数值之间有严格的线性关系。利用阳性标准样品的Ct值，制成标准曲线，再根据未知样品的Ct值就可以准确确定起始DNA的数量。高纯度探针和适宜的镁离子浓度是该方法准确定量的关键。实时定量PCR方法有效地解决了其他定量方法所存在的假阳性及定量准确度不高的难题。     

基于TaqMan MGB探针的葡萄茎枯病菌实时荧光PCR检测方法

 葡萄茎枯病菌是我国进境植物检疫性有害生物。带菌植物材料是病害传播的重要载体,准确、灵敏、快速的检测方法是严格执行口岸检疫措施及研究病害防控措施的有力工具。根据葡萄茎枯病菌及其近似种的细胞骨架蛋白(Actin)基因序列差异,设计并合成1对引物和1条特异性TaqMan-MGB探针,建立了葡萄茎枯病菌的实时荧光PCR检测方法。通过对反应体系的优化,确定了葡萄茎枯病菌的实时荧光PCR最佳反应条件:引物终浓度为0.6 μmol·L^-1,探针终浓度为0.6 μmol·L^-1。灵敏度试验结果显示,最低检测限为总DNA含量20 pg(20 μL反应体系)。此方法快速灵敏,整个反应1 h即可完成,检测过程完全闭管,无需PCR产物后续处理,为快速检测葡萄茎枯病菌提供了重要参考。该方法用于口岸疑似菌株检测,可成功检测出葡萄茎枯病菌。本研究建立的基于TaqMan MGB探针的荧光定量PCR检测方法为葡萄茎枯病菌的早期快速检测监测提供了有力工具。     

条锈菌诱导的小麦EF手钙离子绑定蛋白基因TaCab1的功能初步分析

 根据小麦EF手钙离子绑定蛋白(TaCab1)基因序列,利用WMD3软件设计特异的人工miRNA (amiRNA),构建VIGS沉默载体。利用amiRNA-VIGS体系,对小麦的TaCab1基因的功能进行了初步分析。利用Northern blot和实时定量PCR技术分别检测了amiRNA的积累及TaCab1的沉默效率,并利用显微观察技术统计条锈菌侵染小麦后的组织学差异。结果表明,amiRNA可以得到有效的积累,其靶标基因TaCab1可以得到有效的沉默。从表型上看,小麦叶片上条锈菌夏孢子的产孢量也在一定程度上有所降低。组织学观察发现当TaCab1被沉默后,寄主细胞的坏死面积在侵染后期明显增大,条锈菌的菌丝分枝数也明显增多,但菌丝长度明显变短。     

The choice of target site is crucial in artificial miRNA-mediated virus resistance in transgenic Nicotiana tabacum

MicroRNAs (miRNAs) are negative regulators of gene expression via mRNA degradation or translational repression. The potential of artificial miRNAs (amiRNAs) as antiviral agents has been used in plant biotechnology. In this study, we designed eight amiRNAs derived from Potato Virus Y (PVY) Coat Protein RNA sequences and generated transgenic tobacco plants to express these amiRNAs to confer virus resistance against PVY. Together with transient assays, the hairpin amiRcp precursors that mimic natural miRNA precursor molecules proved to be effective in expressing amiRcps and silencing the target gene. Virus resistance assay revealed that not all amiRcps targeting viral CP sequence are equally effective in preventing PVY infection. Plants with amiRcp-8 targeting the 3′ end (nt735–nt754) region exhibited high virus resistance up to 64.69%. The amiRcp-6 harboring RNA sequence (nt567–nt586) induced the lowest percentages with only 17.05%. Besides, northern blots showed that there was a correlation between the resistance level and the accumulation of amiRNA expression. Furthermore, we used bioinformatics approach to predict the mRNA structure and found that targeting sequences of loose structure benefit to improve the virus resistance level. Our results indicate that the selection of appropriate target sequence is crucial for transgenic plant against virus and provide useful guideline for the design of pathogen-derived amiRNAs.     

Simultaneous one-tube quantification of host and pathogen DNA with real-time polymerase chain reaction

ABSTRACT Phaeocryptopus gaeumannii is a widespread foliar parasite of Douglas-fir. Although normally innocuous, the fungus also causes the defoliating disease Swiss needle cast in heavily infected needles. The extent of P. gaeumannii colonization in Douglas-fir foliage was estimated with real-time quantitative polymerase chain reaction (PCR) using TaqMan chemistry. In order to derive a normalized expression of colonization, both pathogen and host DNA were simultaneously amplified but individually detected by species-specific primers and TaqMan probes labeled with different fluorescent dyes. Detection of host DNA additionally provided an endogenous reference that served as both an internal positive control and adjusted for variation introduced by sample-to-sample differences in DNA extraction and PCR efficiencies. The genes employed for designing the TaqMan probes and primers were beta-tubulin for the pathogen and a LEAFY/FLORICAULA-like gene involved in floral development for the tree host. Both probe/primer sets exhibited high precision and reproducibility over a linear range of 4 orders of magnitude. This eliminated the need to analyze samples in multiple dilutions when comparing lightly with heavily infected needles. Quantification of the fungus within needles was successful as early as 1 month after initial infection. Real-time PCR is the only method currently available to quantify P. gaeumannii colonization early in the first year of the colonization process.     

番茄褪绿病毒SYBR Green I实时荧光定量PCR方法

 根据番茄褪绿病毒(Tomato chlorosis virus, ToCV)热激蛋白70(Hsp70)的基因序列,设计ToCV实时荧光定量PCR特异引物。利用重组质粒ToCV-1为标准品建立SYBR Green I实时荧光定量方法。针对引物浓度、退火温度、特异性、灵敏度、重复性和稳定性进行系列优化。结果表明,最适退火温度为63℃,最适引物浓度为0.3 μmol·L^-1。熔解曲线为特异性单峰,表明其特异性良好。建立的SYBR Green I实时荧光定量PCR较常规PCR灵敏100倍,且具有良好的重复性和稳定性。基于SYBR Green I实时荧光定量PCR技术建立的ToCV检测方法,速度快、特异性强、灵敏度高、重复性好,可以用于ToCV的定量检测。     

应用实时荧光PCR检测苹果果实球壳孢腐烂病菌

根据苹果果实球壳孢腐烂病菌(Sphaeropsis pyriputrescens Xiao&J.D.Rogers)ITS区序列设计特异性引物和TaqMan荧光探针,建立了苹果果实球壳孢腐烂病菌的实时荧光PCR检测方法。该方法能够特异性检测苹果果实球壳孢腐烂病菌,供试的目标菌株检测结果为阳性,而苹果轮纹病菌、苹果炭疽病菌、苹果干腐病菌和苹果褐腐病菌、苹果腐烂病菌等5种对照菌株检测结果为阴性。该方法具有快速、简便、准确的优点,适合于该病害的快速诊断和口岸检验检疫运用。     

The development of a validated real-time (TaqMan) PCR for detection of Stagonosporopsis andigena and S. crystalliniformis in infected leaves of potato and tomato

Stagonosporopsis andigena and S. crystalliniformis are serious foliage pathogens on potato (Solanum tuberosum) and tomato (Solanum lycopersicum). As both species have been recorded only in the Andes area, S. andigena is listed as an A1 quarantine organism in Europe. The actin region of isolates of Stagonosporopsis and allied species of Boeremia, Didymella, Peyronellaea and Phoma was amplified using generic primers. DNA sequence differences of the actin gene were utilised to develop species-specific real-time (TaqMan) PCR assays for the detection of S. andigena and S. crystalliniformis in leaves of potato or tomato. The specificity of the TaqMan PCR assays was determined on genomic DNA extracted from two S. andigena and two S. crystalliniformis isolates and 16 selected isolates of Stagonosporopsis, Phoma and Boeremia, which are the closest relatives. The validation of the methods developed included the DNA extraction and the TaqMan PCR assays. The performance criteria specificity, analytical sensitivity, reproducibility, repeatability and robustness of the TaqMan PCR assays demonstrated the reliability of both methods for the detection of S. andigena and S. crystalliniformis in leaf material. The TaqMan PCR assays were tested on symptomatic leaves of potato and tomato that were obtained after artificial inoculation of detached leaves with both pathogens under quarantine conditions. In the artificial inoculation experiments both S. andigena and S. crystalliniformis caused leaf infections on potato and tomato.