抗病毒转基因葡萄

抗病毒转基因葡萄被葡萄扇叶病毒（ＧｒａｐｅｖｉｎｅＦａｎｌｅａｆＶｉｒｕｓ）侵染的葡萄植株短矮、叶黄、枝条多节扭曲,造成葡萄减产。该病毒经过土壤中的线虫（Ｘｉｐｈｉｎｅｍａｉｎｄｅｘ或Ｘ．ｄｉｖｅｒｓｉｃａｕｄａｔｕｍ）媒体传播。它们啃咬葡萄树根获取...     

生物素标记GFV—cDNA探针的制备及在检测葡萄扇叶病毒上的应用

以整合到质粒中的ＧＦＶ－ｃＤＮＡ为模板经ＰＣＲ合成了生物素标记的ＧＦＶ单、双链探针。用合成的探针对提纯的ＧＦＶ－ＲＮＡ２、感染ＧＦＶ的昆诺藜叶及１８株葡萄进行ＤＮＡ－ＲＮＡ杂交检测表明：检测提纯病毒ＲＮＡ２的灵敏度为１．５ｐｇ／斑点,感染ＣＦＶ的昆诺提取液最高稀释度可达４０９６０倍;１１株显示典型扇叶症状的样品均为阳性,且汁液稀４００～８００倍仍能测出,７株不显示典型扇叶症状的葡萄中３株受到ＧＦＶ     

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《病毒学》2010.7 葡萄扇叶病毒 本期封面上我们看到的是一串鲜嫩欲滴的葡萄……也许不全是!在诱人的葡萄中间还夹杂着一个伪装得很好的坏家伙,它就是我们今天的主角——葡萄扇叶病毒。     

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<正>《病毒学》2010.7葡萄扇叶病毒本期封面上我们看到的是一串鲜嫩欲滴的葡萄……也许不全是!在诱人的葡萄中间还夹杂着一个伪装得很好的坏家伙,它就是我们今天的主角——葡萄扇叶病毒。     

金黄色葡萄球菌协同凝集试验快速检测葡萄扇叶病毒

葡萄扇叶病毒(GFV)是葡萄病毒中广泛传布和危害最大的病毒之一。近年来盲目引种使葡萄园内GFV危害只增不减。利用茎尖组织培养或结合热处理是选育脱GFV葡萄组培苗的     

葡萄扇叶病毒外壳蛋白基因的克隆,序列分析及其在大肠杆菌中…

通过ＲＴ－ＰＣＲ方法把葡萄扇叶病毒（ＧＦＬＶ）外壳蛋白基因（ＣＰ ｇｅｎｅ）分成两部分扩增,扩增产物克隆入ｐｇＥＭ－５Ｚｆ（＋）载体,并通过ＢｇｌⅡ位点连接成一完整的外壳蛋白基因,通过序列分析测得全长外壳蛋白基因为１５１２ｂｐ,编码５０４个ＡＡ＇ｓ与国外株系ＧＦＬＶ－Ｆ１３相比,核苷酸同源性为８８．４％,氨基酸同源性为９５．８％。并且这一外壳蛋白基因在大肠杆菌Ｅ． ｃｏｌｉＤＨ－５α中得到了表达。     

生物素标记GFV－cDNA探针的制备及在检测葡萄扇叶病毒上的应用

以整合到质粒中的ＧＦＶ－ｃＤＮＡ为模板经ＰＣＲ合成了生物素标记的ＧＦＶ单、双链探针。用合成的探针对提纯的ｃＦＶ－ＲＮＡ＿２、感染ＣＦＶ的昆诺藜叶及１８株而萄进行ＤＮＡ－ＲＮＡ杂交检测表明：检测提纯病毒ＲＮＡ＿２的灵敏度为１．５ｐｇ／斑点,感染ＧＦＶ的昆诺藜提取液最高稀释度可达４０９６０倍;１１株显示典型扇叶症状的样品杂交结果均为阳性,且汁液稀释４００～８００倍仍能测出,７株不显示典型扇叶症状的葡萄中３株受到ＧＦＶ的侵染。单、双链探针最适使用浓度分别为１／２００及１／１００。     

葡萄试管苗热处理结合茎尖培养脱病毒效果的研究

对７个生食葡萄品种的试管苗热处理结合茎尖剥离培养脱除病毒的方法做了研究,结果表明,从热处理试管苗剥离的茎尖培养成活率为６１．２％,其中有１８．１％的成苗。各品种热处理试管苗剥离的茎尖分化再生能力不同：先形成愈伤组织的成苗率较低,而先分化芽的茎尖成苗率较高。这一方法对扇叶病毒和卷叶病毒的脱除率达９２％以上。     

葡萄卷叶病毒的纯化、血清学研究及其在脱毒组培苗检测中的应用

将具有典型葡萄卷叶病(Grapevine leafroll diseas,GLRD)症状的葡萄组织,经差速和硫酸铯—蔗糖密度梯度离心,提纯了GLRV,并制备了兔抗血清。电镜下可观察到长度从600～2000nm的线形病毒颗粒,其中以1400nm左右为主。免疫电镜结果表明线形病毒颗粒能被美国的NY-1分离株抗血清(Ⅲ型)所修饰。在间接ELISA中提纯制品与GLRV的Ⅲ、Ⅳ、Ⅱ型抗血清均能产生免疫反应。与Ⅲ型抗血清产生较强的免疫反应,Ⅳ型次之,Ⅱ型最弱。在SDS-免疫双扩散实验中病组织韧皮部粗提液与GLRV的Ⅲ,Ⅳ、Ⅱ型抗血清均产生免疫沉淀线。从而推测我国葡萄园内的葡萄卷叶病很可能由2种或3种卷叶病毒感染所致.采用A蛋白夹心酶联免疫吸附试验(PAS-ELISA)检测葡萄试管苗,Ⅲ型抗血清和自制抗血清的平行测试结果基本相符,共获得11个生食葡萄和10个山葡萄品种的脱葡萄卷叶病毒和扇叶病毒的组培苗,扩繁后田间试种表现出良好的农艺性状。     

葡萄卷叶病毒的纯化,血清学研究及其在脱毒组培苗检测中的应用

将具有典型葡萄卷叶病(Grapevine leafroll diseas,GLRD)症状的葡萄组织,经差速和硫酸铯—蔗糖密度梯度离心,提纯了GLRV,并制备了兔抗血清。电镜下可观察到长度从600～2000nm的线形病毒颗粒,其中以1400nm左右为主。免疫电镜结果表明线形病毒颗粒能被美国的NY-1分离株抗血清(Ⅲ型)所修饰。在间接ELISA中提纯制品与GLRV的Ⅲ、Ⅳ、Ⅱ型抗血清均能产生免疫反应。与Ⅲ型抗血清产生较强的免疫反应,Ⅳ型次之,Ⅱ型最弱。在SDS-免疫双扩散实验中病组织韧皮部粗提液与GLRV的Ⅲ,Ⅳ、Ⅱ型抗血清均产生免疫沉淀线。从而推测我国葡萄园内的葡萄卷叶病很可能由2种或3种卷叶病毒感染所致.采用A蛋白夹心酶联免疫吸附试验(PAS-ELISA)检测葡萄试管苗,Ⅲ型抗血清和自制抗血清的平行测试结果基本相符,共获得11个生食葡萄和10个山葡萄品种的脱葡萄卷叶病毒和扇叶病毒的组培苗,扩繁后田间试种表现出良好的农艺性状。     

Grapevine fanleaf virus (GFLV)-specific antibodies confer GFLV and Arabis mosaic virus (ArMV) resistance in Nicotiana benthamiana

Grapevine fanleaf virus (GFLV) is one of the most destructive pathogens of grapevine. In this study, we generated monoclonal antibodies binding specifically to the coat protein of GFLV. Antibody FL₃, which bound most strongly to GFLV and showed cross-reactivity to Arabis mosaic virus (ArMV), was used to construct the single-chain antibody fragment scFvGFLVcp-55. To evaluate the potential of this single-chain variable fragment (scFv) to confer antibody-mediated virus resistance, transgenic Nicotiana benthamiana plants were generated in which the scFv accumulated in the cytosol. Recombinant protein levels of up to 0.1% total soluble protein were achieved. The T₁ and T₂ progenies conferred partial or complete protection against GFLV on challenge with the viral pathogen. The resistance to GFLV in transgenic plants was strictly related to scFvGFLVcp-55 accumulation levels, confirming that the antibody fragment was functional in planta and responsible for the GFLV resistance. In addition, transgenic plants conferring complete protection to GFLV showed substantially enhanced tolerance to ArMV. We demonstrate the first step towards the control of grapevine fanleaf degeneration, as scFvGFLVcp-55 could be an ideal candidate for mediating nepovirus resistance.     

Molecular Characterization of Whole Genomic RNA2 From Iranian Isolates of Grapevine Fanleaf Virus

Grapevine fanleaf virus (GFLV) is the major causal agent of the grapevine degeneration disease. To characterize the genomic RNA2 segment from Iranian isolates of GFLV, leaf samples were collected from infected vineyards in different locations with a long history of vine cultivation. Four isolates were selected for cloning and sequencing on the basis of the restriction profiles of RT‐PCR products. The sequencing data revealed that the RNA2 of the Iranian GFLV isolates were the shortest compared with that of all previously described GFLV isolates. The sizes were 3730 nucleotides (nt) for Shir‐Amin and Urmia isolates and 3749 nt for Takestan and Bonab isolates (excluding the poly (A) tail), due to deletion events in both 5′ and 3′ non‐coding regions. In the phylogenetic tree based on the full‐length nucleotide sequences of GFLV RNA2, all the GFLV isolates clustered into two groups with the exception of the Hungarian isolate (GHu). The Iranian isolates grouped as a distinct cluster. Recombination analyses showed that GFLV‐NW (Germany), GFLV‐F13 (reference isolate), GFLV isolate Shir‐Amin (Iran) and Arabis mosaic virus isolate Lv were recombinant isolates and one of their parents belonged to the same lineage as the Iranian isolates. These findings suggest that these isolates originated from a common ancestor.     

两种DNA探针杂交检测结核分支杆菌方法的研究

为改进结核杆菌DNA探针的特异性与实用性,研制了以生物素标记的两种对结核分支杆菌特异的DNA探针:一个5’端标记的20bp的寡核苷酸探针和一个采用PCR方法合成的188bp长链探针。两种探针分别与结核分支杆菌的全染色体DNA,以及基因组上IS6110序列的一段317bp的PCR扩增产物进行斑点杂交,以碱性磷酸酶(AP)催化的染色反应检测,测试了两个探针的敏感性和特异性。系统地比较研究了两种探针杂交检测条件:探针的浓度选择,杂交温度与洗膜温度的选择,以及杂交与洗膜温度对检测的敏感性与特异性的影响。寡核苷酸探针和188bp探针杂交检测纯化结核分支杆菌基因组DNA的敏感性分别为100ng与6ng,杂交检测PCR产物的敏感性分别是400pg与50pg。两探针的最佳杂交浓度均为40～160ng/ml,最佳杂交温度分别是42℃与68℃,最佳洗膜温度分别是60℃与60～68℃之间。两种探针均仅与结核分支杆菌及BCG有杂交信号,而与其它受试分支杆菌及非分支杆菌杂交结果都呈阴性。它们的特异性都很强,但188bp探针的敏感性约是寡核苷酸探针的7～16倍,而且188bp探针检测本底较低,是检测结核分支杆菌的较佳选择     

Biotin-Avidin ELISA Detection of Grapevine Fanleaf Virus in the Vector Nematode Xiphinema index

The value of biotin-avidin (B-A) ELISA for the detection of grapevine fanleaf virus (GFLV) in Xiphinema was estimated with field populations and greenhouse subpopulations. Samples consisted of increasing numbers of adults ranging from 1 to 64 in multiples of two. Tests with virus-free X. index populations reared on grapevine and fig plants as negative controls did not reveal a noticeable effect of the host plant. ELISA absorbances of virus-free X. index samples were greater than corresponding absorbances of X. pachtaicum samples. Differences occurred between two X. index field populations from GFLV-infected grapevines in Champagne and Languedoc. In most tests, 1-, 2-, 4-, and 8-nematode samples of virus-free and virus-infected populations, respectively, could not be separated. Consequently, B-A ELISA was not a reliable method for GFLV detection in samples of less than 10 X. index adults, but comparison of the absorbances obtained with increasing numbers may allow differentiation of the viral infectious potential of several populations.     

High-Sensitivity Detection of Fruit Tree Viruses Using Bacterial Magnetic Particles

Prunus necrotic ring spot virus (PNRSV) and grapevine fanleaf virus (GFLV) were detected by fluoroimmunoassay using bacterial magnetic particles (BMPs),and a double antibody sandwich enzyme linked immunosorbent assay (DAS-ELISA).For the fluoroimmunoassay,fluorescein isothiocyanate labeled anti-PNRSV antibody or anti-GFLV antibody was conjugated onto BMPs of Magnetospirillum gryphiswaldense MSR-I.With this method,a very low minimum antigen concentration (1 x 106 dilution of the original sample concentration) could be detected.Using DAS-ELISA,the minimum antigen detection concentration was the original sample concentration.Thus,comparing these two methods,a BMP-based method could increase the sensitivity up to six orders of magnitude (106) higher than an ELISA-based method of detection PNRSV and GFLV.     

RNA oligoprobe capture RT-PCR, a sensitive method for the detection ofGrapevine fanleaf virus in Tunisian grapevines

A simple, sensitive and specific RNA capture method is described for the detection of Grapevine fanleaf virus (GFLV) in infected grapevines. This method consists of hybridizing GFLV-RNAs to oligoprobes immobilized on nylon membranes, followed by RT-PCR amplification of targeted viral sequences. The RNA oligoprobe capture RT-PCR method is 10-fold more sensitive than IC-RT-PCR. The efficiency of the RNA oligoprobe capture RT-PCR and the reuse of immobilized oligoprobe membranes without loss of efficiency could make this procedure suitable for the routine diagnosis of GFLV in grapevines.     

Molecular characterization of grapevine plants transformed with GFLV resistance genes: I

The Grapevine FanLeaf Virus-Coat Protein (GFLV CP) gene was inserted through Agrobacterium-mediated transformation in Vitis vinifera ‘Nebbiolo’, ‘Lumassina’ and ‘Blaufränkisch’. Two plasmids were used: pGA-CP+ (full-length GFLV CP gene with an introduced start codon) and pGA-AS (same gene in antisense orientation). Forty-three transgenic lines were regenerated. As several lines in Southern blots share same hybridization patterns, eight independent line groups resulted for ‘Nebbiolo’, one for ‘Lumassina’, and two for ‘Blaufränkisch’. Inserted T-DNA copies ranged from one to three; one line probably contains an incomplete copy of T-DNA. Except for one ‘Nebbiolo’ line, no evidence for methylation of the transgene at cytosine residues was found by Southern analyses. Specific mRNA was present at variable expression levels; some lines accumulated the coat protein while in others the protein was not detectable by ELISA.