烟草抗马铃薯Y病毒病相关基因NtPsaN的克隆及表达分析

【目的】从高抗PVY烟草品种VAM中克隆抗病相关基因,分析该基因的序列特征、进化关系和表达特性,研究其在烟草抗PVY防御反应中的作用,为培育抗PVY烟草新品种奠定基础。【方法】利用SSH结合cDNA芯片筛选出来的病害诱导特异表达基因片段,通过RACE技术克隆烟草抗病相关基因;生物信息学分析该基因保守结构域以及序列特征;采用MEGA4.0软件构建系统进化树;利用实时荧光定量RT-PCR技术研究该基因的表达特性。【结果】克隆了1个烟草抗病相关基因,命名为NtPsaN,该基因具有PsaN基因家族保守结构域,OFR长度507bp,编码168个氨基酸;构建了PsaN亚基系统进化树;实时荧光定量RT-PCR结果显示接毒之后该基因表达与不接毒对照相比有明显上调趋势。【结论】克隆得到一个烟草PVY抗病相关基因NtPsaN,其表达受PVY侵染诱导,该基因可能在烟草抵御PVY病害侵染过程中起重要作用。     

NtMAP70基因在烟草抗马铃薯Y病毒过程中的作用

为了探明微管结合蛋白70(MAP70)在抗马铃薯Y病毒(PVY)中的作用机制,克隆了烟草Nt MAP70基因的全长,并进行了生物信息学分析.利用实时荧光定量PCR研究了该基因在烟草不同时期和不同部位中的表达水平,结果表明,NtMAP70在烟草的各个生长期均有表达,且在根中的表达量最高.构建了基于双生病毒卫星诱导的烟草Nt MAP70的沉默载体,以中国番茄黄化曲叶病毒(TYLCCNV)为辅助病毒在烟草中沉默了该基因.与对照相比,在Nt MAP70基因沉默的烟草中PVY侵染速率明显减缓,病毒含量显著降低.     

靶向加工番茄elF4E1的CRISPR/Cas9载体有效性验证

【目的】验证基于CRISPR/Cas9系统构建的靶向编辑加工番茄(Solanum lycopersicum) eIF4E1基因载体的有效性,为CRISPR/Cas9系统在培育PVY抗性植株中的应用提供技术支持。【方法】构建靶向编辑番茄真核翻译起始因子elF4E1基因的CRISPR/Cas9系统表达载体,用农杆菌渗透法瞬时转化番茄植株,PCR扩增已转化植株靶位点周围DNA序列后用HaeⅢ进行酶切,回收未切开的条带与pGEM-T载体连接后进行单克隆测序。【结果】对测得的9个克隆序列进行比对分析,在PAM (protospacer adjacent motifs)上游的6~8 bp的碱基处均发生突变,并且都为单碱基的替换,导致多肽链中单个氨基酸的替换。【结论】利用CRISPR/Cas9基因组编辑系统构建的载体能够特异性地靶向加工番茄eIF4E1基因,为利用CRISPR/Cas9系统敲除eIF4E1基因,获得抗PVY病毒的番茄育种材料奠定了基础。     

来自安徽不同寄主PVY分离物的血清学鉴定及其cp基因分子进化分析

 Tobacco and potato samples showing symptoms of PVY were collected from different regions in Anhui Province, and the ELISA results of partial samples were positive. The total RNA was extracted from the positive samples by TRIZOL methods. Specific primer pair was designed to amplify cp gene of PVY by RT-PCR. Sequencing results indicated that the full length of cp gene of PVY from tobacco (PVY-CP-4) and pota-to (PVY-CP-7) is 801 nts, and each of them encodes 266 amino acids. A phylogenetic tree based on alignment of cp nucleotide sequences was constructed and the sequence comparing of cp gene was conducted. The results showed that PVY-CP-4 could be grouped into one branch with PVY^O and PVY^N:O and shared the highest sequence similarity (99.4%) with PVY^O (EF026074). It was suggested that PVY-CP-4 derived from tobacco in Hefei might belong to PVY^O. PVY-CP-7 clustered together with PVYN and PVYNTN and formed another branch. Furthermore, PVY-CP-7 shared the highest sequence similarity (98.3%) with PVY^NTN(AJ890347), PVY^NTN (EF026075) and PVY^NTN(AJ585342). It was supposed that PVY-CP-7 derived from potato in Wuhe probably belonged to PVY^NTN.     

马铃薯Y病毒的检测技术

快速、准确检测马铃薯病毒是控制马铃薯病毒危害的有效方法 ,本文全面评述了运用基于抗血清为基础的免疫化学方法和基于核酸分子组成差异的核酸分子标记方法检测PVY的现代植物病毒病原检测技术 ,并比较了各种方法的优点     

Differences in aphid transmissibility and translocation between PVYN and PVYO isolates

The aphid transmissibility and within-plant movement of two PVY isolates belonging to PVY^O and PVY^N strains were studied. Potato plants were infected by Myzus persicae either 1 week after emergence or 30 or 45 days after emergence. Infected leaves, petioles of infected leaves, and different segments of the stems of plants infected 1 week after emergence were ELISA-tested 7, 11 and 14 days after infection. Segments of the plants infected 30 or 45 days after emergence were ELISA tested 30 days after infection. Normalised ELISA values were used for statistical analyses. Virus infection of progeny tubers was assessed by post-harvest inspection. The ability of 15 aphid species to transmit the virus isolates was also examined. There was no difference in the aphid transmissibility of the two isolates 7 or 11 days after exposure to M. persicae. However, normalised ELISA values were significantly affected by both isolate and sampling date 11 and 14 days after M. persicae transmission. The level of infection of different stem segments was significantly affected by both isolate and growth stage of the plant at infection. The proportions of infected leaves, stem segments and progeny tubers were all significantly higher for PVY^N than for PVY^O. PVY^N was more effectively transmitted by a number of different aphid species than was PVY^O. Newly described vectors of PVY^N include Schizaphis graminum, Aphis fabae cirsiacanthoides, Aphis spiraecola, Myzus ligustri, Aphis fabae, Aphis spiraephaga, Myzus cerasi, Macrosiphum rosae, Diuraphis noxia, Aphis pomi and Rhopalosiphum padi, while those of PVY^O include Aphis fabae cirsiacanthoides, Myzus cerasi and Myzus ligustri.     

植物病毒源dsRNA原核表达条件的研究

利用PVYN-CP和PLRV-CP基因构建了dsRNA原核表达载体L4440RYl,转至大肠杆菌HT115(DE3),获得菌株HTRYl。绘制了菌株HTRYl的生长曲线,研究了IPTG浓度和诱导时间对该菌株dsRNA表达量的影响。结果表明,接种3.5h,菌体浓度OD600为0.6,加入终浓度为0.3～0.4mmol/L的IPTG,诱导4～5h时,dsRNA表达量最高。dsRNA表达条件的研究,为dsRNA的应用研究奠定了基础。     

马铃薯Y病毒衣壳蛋白抗原表位分析及其快速ELISA检测方法的建立

【目的】马铃薯Y病毒（potato virus Y,PVY）是影响马铃薯产量和品质的主要病毒之一,目前尚未发现有效的防治药剂,脱毒种薯的应用是预防PVY危害的主要防治措施。建立灵敏度高、特异性强的PVY快速检测方法,为脱毒种薯质量控制提供技术支撑。【方法】将PVY衣壳蛋白（coat protein,CP）分段表达为有重叠部分的小段多肽,以其为抗原通过Western blot分析PVY-CP的抗原表位。以P/N值最大为标准,通过常规双抗夹心ELISA（DAS-ELISA）对识别不同抗原表位的单克隆抗体（monoclonal antibody,MAb）进行配对试验,筛选一组检测效果最优的配对单克隆抗体,并确认捕获抗体和检测抗体。通过方阵滴定法确定捕获抗体及检测抗体的最佳工作浓度,通过控制变量法确定检测抗体与抗原的最佳共同孵育时间。以不同浓度的PVY-CP蛋白为抗原,检验快速DAS-ELISA的灵敏度。以感染不同病毒的马铃薯样品为抗原,检测快速DAS-ELISA的特异性。同时通过快速DAS-ELISA与RT-PCR检测50份田间采集的疑似感染PVY的马铃薯样品,将二者结果相比较检验检测方法的符合率。运用建立的快速DAS-ELISA对不同株系PVY感染的马铃薯样品进行检测。【结果】利用PVY-CP的6条分段表达多肽筛选到一组能进行DAS-ELISA的配对单克隆抗体（9G6和3D3）,并以这对单抗为基础建立了PVY快速DAS-ELISA检测方法。以9G6为捕获抗体包被酶标板,检测抗体3D3经辣根过氧化物酶（horseradish peroxidase,HRP）标记后以2 μg·mL^-1的工作浓度与抗原在37℃共同孵育5 min。该检测方法检测限为0.5 ng·mL^-1,特异性分析结果显示该法仅在检测感染PVY的马铃薯样品时呈阳性反应,检测马铃薯S病毒（potato virus S,PVS）、马铃薯M病毒（potato virus M,PVM）、马铃薯卷叶病毒（potato leaf-roll virus,PLRV）等其他常见马铃薯病毒样品均呈阴性反应。通过快速DAS-ELISA与RT-PCR同时对50份田间采集的马铃薯样品进行检测,有48份样品检测结果一致,符合率达96%,且对PVY^N及PVY^O样品检测结果均呈阳性。【结论】建立的PVY检测方法灵敏度高、特异性强,30 min即可完成检测,方便快捷,为PVY的高通量检测、脱毒种薯的生产提供了关键技术支持。     

马铃薯Y病毒CP基因5′端和3′端反向重复结构介导的抗病性研究

本研究克隆了来源于马铃薯Y病毒坏死株系(PVYN)外壳蛋白(CP)基因(PVYNCP)5′端和3′端的反向重复cDNA序列,并构建了植物表达载体pROKII-5′IR和pROKII-3′IR,利用农杆菌介导的叶盘法转化烟草NC89,分别获得166和126株转基因烟草。抗病性试验表明,转化PVYNCP基因3′端茎50 bp(环50 bp)hp RNA(hairpin RNA)的烟草抗病率达69%,而转化PVYNCP基因5′端相同片段长度的hpRNA的烟草却全部发病。Southern blot结果表明,转基因植株的抗病性与转基因的拷贝数之间无明显的相关性;Northern blot结果表明,目的片段转录产物的积累量与植株的抗病性呈负相关,证明所获得的抗病性是RNA介导的抗病性。研究结果证明PVYNCP基因的3′端比5′端更能有效地诱发基因沉默,并且hpRNA茎部的长度可减少到50 bp。该结果为探索利用CP基因的最短长度和有效部位的基因片段来培育多抗病毒转基因植物提供了依据。     

A survey of tobacco viruses in tobacco crops and native flora in Greece

The most important tobacco producing areas in Greece were surveyed for virus presence, from 1997 to 2000. Tobacco seedlings or plants showing virus-like symptoms were randomly collected from seedbeds or fields, respectively, and tested by ELISA, and/or mechanical inoculation onto indicator plants. Potato virus Y (PVY), Cucumber mosaic virus (CMV) and Tobacco mosaic virus (TMV) were detected in all sampling areas, with TMV mainly found in oriental varieties. Tomato spotted wilt virus (TSWV) consisted a serious endemic virus in Northern Greece (Thrace, Central and Eastern Macedonia), whereas Alfalfa mosaic virus (AMV) was mainly found in regions, where alfalfa was cultivated in the vicinity of tobacco crops. Eggplant mottled dwarf virus (EMDV) was detected in several areas but always in very low incidence (<0.01%). Surveys were also conducted to assess the potential reservoir hosts of PVY, CMV and AMV among weeds collected from highly infected tobacco fields from 1998 to 2000. Among 3450 samples tested for PVY, plants from 17 species in 10 families were found infected. For CMV, 2891 weed samples were tested and 19 species in 12 families were positive. Assays for AMV infection were made on 961 samples and 12 species in 9 families were identified as hosts of this virus.