油棕猝倒病菌实时荧光PCR检测方法

油棕猝倒病菌(Pythiums plendens)是我国进境植物检疫性有害生物。本试验根据P.splendens rDNA ITS区序列,设计了实时荧光PCR引物pyspF/pyspR及荧光探针pyspT,建立了P.splendens荧光PCR检测方法,检测灵敏度为0.012pg/μL。     

实时荧光PCR检测瓜炭疽病菌

采用实时荧光PCR技术建立了瓜炭疽病菌(Colletotrichum orbiculare)的检测方法。根据瓜炭疽病菌甘油醛-3-磷酸脱氢酶(GAPDH)基因和谷氨酰胺合成酶(GS)基因序列,设计了该病菌特异性引物和TaqMan探针,并对所设计的引物和探针的反应条件进行了优化。采用本试验建立的实时荧光PCR方法对瓜上的其他菌株及近似菌株进行检测,可将瓜炭疽病菌与其他病原菌区分开。灵敏度试验表明,25μL体系中只要有39.6pg的核酸量就可以被检测到,检测灵敏度达到1.584pg/μL,比普通PCR检测灵敏度高100倍。同时对田间采集的病株和未知样品进行的检测证明了引物和TaqMan探针的特异性。     

油菜茎基溃疡病菌的实时荧光PCR检测

 根据油菜茎基溃疡病菌Leptosphaeria maculans与其近似种ITS序列的差异,设计了检测L. maculans的引物Lmb3/R2和探针Probe-M,建立了L. maculans的实时荧光PCR检测方法。试验结果表明,来自加拿大、澳大利亚和乌克兰等国的22株L. maculans菌株都能得到阳性扩增,而供试的30株L. biglobosa菌株和6株其他菌株以及空白对照没有荧光信号的增加。该检测方法的灵敏度达到4 pg菌丝DNA,整个检测过程控制在4 h内,其快速、特异和灵敏的特点可以满足进境油菜籽样品的快速初检以及病菌分离物的快速鉴定。     

番茄细菌性溃疡病菌的实时荧光PCR检测

 由Clavibacter michiganensis subsp.michiganensis(Cmm)引起的番茄细菌性溃疡病是一种严重危害番茄生产的种传细菌性病害。根据ITS序列多态性设计引物及TaqMan探针进行实时荧光PCR检测的结果表明,这组引物一探针能检测出所有供试的Cmm菌,对照菌均未检测到荧光信号。用接种但未显示症状的番茄苗叶片及人工处理的带菌种子提取的核酸作为模板,均能检测到病菌,其检测灵敏度比常规PCR高约100倍。实验中不需病原菌的分离培养及PCR的后续处理。该方法快速、简便、安全、准确,适用于出入境检验检疫及种子、种苗健康检测领域。     

梨火疫病菌的实时荧光PCR检测

 根据梨火疫病菌16S~23S间的ITS保守序列,设计并合成了一对特异性引物REA/FEA,应用荧光染料SYBR Green I,对10个梨火疫的菌株和其它相关参试菌株进行了检测。结果表明,10个梨火疫菌株都产生荧光信号而其它参试菌株都不产生荧光信号,成功建立了梨火疫病菌的实时荧光PCR检测方法。整个检测过程只需3h,完全闭管,降低了污染的机会,无需PCR后处理。检测的灵敏度是4个菌体细胞,比常规PCR电泳检测提高了10倍。用该特异性引物对梨枝条浸泡液进行实时荧光PCR检测,结果可特异性检测到目标菌的存在,并且检测的灵敏度是24个菌体细胞,比常规PCR电泳检测提高10倍。     

实时荧光PCR检测马铃薯白线虫技术研究

马铃薯胞囊线虫是马铃薯上最重要的有害生物之一,也是我国特别关注的重要植物检疫性线虫.针对马铃薯白线虫ITS序列,我们设计了引物和TaqMan探针,使用15种马铃薯胞囊线虫群体和4种其它胞囊线虫样品进行验证,可高度灵敏地检测单个马铃薯白线虫的胞囊或幼虫,最高检测灵敏度达到10fs;同时开展了混合样品和未知样品的检测,证明了引物的专化性和TaqMan探针特异性.该检测方法可自动化检测马铃薯白线虫并进行定量,适合进行标准化的常规检测.     

利用实时荧光PCR技术检测风信子黄腐病菌

风信子黄腐病菌是我国禁止入境的病原细菌之一,我国目前尚无该病的发病报道.本研究根据风信子黄腐病菌基因组16S-23S ribosomal RNA intergenic spacer保守序列,设计并合成了1对特异性引物和1条具有稳定点突变特异性探针进行实时荧光PCR检测,风信子黄腐病菌有很强的荧光信号,供试的其它7种病原细菌菌株均没有荧光产生.与常规PCR相比,实时荧光PCR检测特异性强,灵敏度高,适合病害的快速诊断和口岸检验检疫应用.经优化反应条件,建立了稳定的风信子黄腐病菌实时荧光PCR检测方法.     

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。     

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。     

应用TaqMan探针进行马铃薯金线虫实时荧光PCR检测技术研究

马铃薯孢囊线虫是全球性的植物检疫性线虫,亦是我国重点关注的有害生物。针对马铃薯金线虫ITS序列,设计了引物和TaqMan 探针,使用15个马铃薯孢囊线虫群体和4个其他孢囊线虫样品进行验证,可高度灵敏地检测单个马铃薯金线虫的孢囊或幼虫,并可进行定量;最高检测灵敏度达到10fg;同时开展了混合样品和未知样品的检测,证明了引物的专化性和TaqMan探针的特异性。该检测方法可自动化检测马铃薯金线虫并进行定量,适合进行标准化的常规检测。     

一种引起茄科作物病害的病原:Candidatus Liberibacter solanacearum

Candidatus Liberibacter solanacearum是Liefting等人于2009年鉴定并命名的一种能够引起茄科作物病害的新病原,该病菌可引起茄科作物植株矮化、畸形并造成巨大的经济损失。目前该病菌在我国尚无分布。本文从病原鉴定、寄主范围、地理分布、传播途径、危害情况及防控措施等几方面对该病菌进行了简要介绍,以期引起重视,并为防范其入侵提供参考。     

Detection by PCR of Candidatus Liberibacter asiaticus, the bacterium causing citrus huanglongbing in vector psyllids: application to the study of vector–pathogen relationships

Citrus huanglongbing (HLB), previously called greening, is a serious citrus disease in Asia, eastern and southern Africa. It is caused by Candidatus Liberibacter asiaticus (Las), a phloem-limited, nonculturable bacterium transmitted by the Asian citrus psyllid ( Diaphorina citri ) in Asia. A PCR-based assay was developed for monitoring Las in vector psyllids using a rapid DNA extraction from psyllid bodies and PCR amplification. The entire procedure for Las detection in psyllids can be completed within 5 h. Using this method, Las can be accurately detected in psyllid adults as well as nymphs in different instar stages. The assay is sensitive enough for Las detection in single-psyllid extract from adult, fifth, fourth and third instars. In a transovarial transmission experiment, Las was not detected in eggs or in offspring produced by Las-carrying psyllid females. In a retention test, the Las-carrying psyllids remained Las-positive for 12 weeks after they were moved to common jasmine orange, a Las-immune plant. From these experimental results it was concluded that Las persists in the Asian citrus psyllid vector, but is not transovarially transmitted by the vector. These data help in understanding epidemiological characteristics of Las and psyllids in citrus HLB.     

Economic justification for quarantine status – the case study of ‘Candidatus Liberibacter solanacearum’ in the European Union

International agreements on plant health and trade require that regulating a pest should be justified by economic impact assessment. Economic impact assessments are usually qualitative, weakening the objective and transparency of the regulation decision. This study assessed the potential economic impacts of the invasion of the plant pathogenic bacterium ‘Candidatus Liberibacter solanacearum’ into the European Union in order to economically justify a decision on its quarantine status. Direct economic impacts resulting from yield loss in potato and tomato were computed using partial budgeting at a regional scale, while total economic impacts on the potato and tomato markets were computed using partial equilibrium modelling at the EU scale. Annual direct impacts at the most likely infestation level were estimated at €222 m for the whole EU. Uncertainty analysis showed a distribution of foreseeable annual impacts with a 5th percentile of €192 m, and a 95th percentile of €512 m. Increased market prices of potato and tomato resulting from reduced supply were found to increase profits for non‐infested producers and to compensate in part for the production losses of infested producers, with consumers paying for this mitigation of impacts on producers. The expected negative impact on societal welfare at the most likely infestation level is less than the estimated direct impacts, viz. €114 m/year. The potential economic impacts of ‘Ca. L. solanacearum’ in the European Union are demonstrably of major importance. Therefore, a decision to categorize this organism as a quarantine pest is supported.     

柑橘黄龙病常规PCR检测技术研究与初步应用

柑橘黄龙病是世界范围具有毁灭性危害的柑橘细菌性病害,在我国大部分柑橘产区发生,严重制约了我国柑橘产业的发展。本文根据黄龙病病原物亚洲韧皮杆菌核糖体16SrRNA基因设计了1对PCR引物HLBF468/HLBR877,并以此为基础建立了常规PCR反应体系,确定了检测体系的特异性和灵敏度。结果表明该体系的检测灵敏度比先前报道的常规PCR方法有了明显提高。利用建立的PCR体系完成了对广东和广西两省区果园柑橘黄龙病的抽样检测。本研究建立的常规PCR方法可以作为一种简便、准确、灵敏的检测技术应用于柑橘黄龙病的早期诊断。     

土壤中烟草根黑腐病菌的实时定量PCR检测技术研究

 Thielaviopsis basicola is a soil-borne plant pathogen which causes root rot disease in tobacco plants. Detection and monitoring of T. basicolain soil is of great significance to control this disease. Based on the differences in internal transcribed spacer (ITS) sequences of T. basicola and other fungal pathogens, a specific primer pair Tb1/Tb2 for T. basicolawas developed. The results showed that the primer pair gave a single amplicon of 330 bp from T. basicola and revealed no undesirable cross-reaction with other seven soil-borne pathogen isolates and three tobacco rhizosphere dominant fungi isolates. With a series of 10-fold genomic DNA dilutions of T. basicola, the detection limit of 1 pg/μL in conventional PCRand100 fg/μL in real-time quantitative PCR was achieved. With DNA from the soil inoculated with different numbers of T. basicola conidia, the detection limit was 10 conidia per reaction in conventional PCR and 0.4 conidia per reaction in real-time quantitative PCR.     

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TaqMan探针实时荧光PCR方法检测香石竹细菌性萎蔫病菌

 根据香石竹细菌性萎蔫病菌基因组16S-23S rRNA保守序列,设计并合成了一对特异性引物和一条具有稳定点突变特异性探针,建立了对香石竹细菌性萎蔫病菌的TaqMan实时荧光PCR检测方法。除香石竹细菌性萎蔫病菌外,还对其他7种病原细菌菌株进行了荧光PCR检测。结果表明,只有香石竹细菌性萎蔫病菌产生荧光,其他病原细菌均没有荧光产生。与常规PCR相比,实时荧光PCR检测特异性强,灵敏度高,能检测到浓度为0.4 pg/μL的DNA,且能直接用于苗木等样品的检测,适合病害的快速诊断和口岸检验检疫应用。      

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.