草莓镶脉病毒侵染性克隆的构建

 利用草莓镶脉病毒(Strawberry vein banding virus, SVBV)全长克隆pSVBV-E3构建SVBV侵染性克隆。pSVBV-E3经限制性内切酶酶切分别获得0.5-mer SVBV和1.0-mer SVBV,依次正向插入植物表达载体pBINPLUS,成功构建侵染性克隆重组质粒pBIN-1.5SVBV。pBIN-1.5SVBV转化农杆菌,分别接种森林草莓(Fragaria vesca)和4种烟草属植物(Nico-tiana spp.)验证其侵染性。结果表明,SVBV侵染性克隆接种森林草莓8周后发病,表现出典型的叶脉镶边黄化症状,PCR法可以从显症森林草莓中检测出SVBV cp基因,Southern blot法可以检测出SVBV基因组。而接种4种烟草属植物8周后未观察到发病症状,PCR法也未检测出SVBV cp基因。构建的SVBV侵染性克隆经接种验证能够侵染森林草莓,为进一步研究SVBV侵染森林草莓的致病机制奠定了基础。     

草莓镶脉病毒ORF Ⅱ基因的克隆、原核表达与抗血清制备

 用CTAB法从感染草莓镶脉病毒（Strawberry vein banding virus, SVBV）的草莓叶片中提取总DNA,设计特异性引物扩增SVBV中国分离物ORF Ⅱ基因,克隆并测序。结果表明,SVBV中国分离物ORF Ⅱ基因全长486 nts,编码161个氨基酸。将其与SVBV美国分离物以及花椰菜花叶病毒属其他成员的ORF Ⅱ基因相比较,结果表明,SVBV中国分离物 ORF Ⅱ基因与SVBV美国分离物的核苷酸序列相似性最高,达91.2%。将SVBV ORF Ⅱ基因插入原核表达载体pET32a（+）,重组质粒pET-ORF Ⅱ转化大肠杆菌BL21（DE3）。经IPTG诱导及Ni²⁺-NTA亲和柱纯化,获得分子质量约为38 kDa的融合蛋白。以此纯化的融合蛋白为抗原免疫家兔,可以制备出高效价的抗血清。Western blot分析表明,制备的抗血清能与重组融合蛋白发生特异性反应。利用抗血清进行ELISA测定,能够检测出感病草莓植株病汁液中SVBV ORF Ⅱ基因表达的蛋白。     

葡萄浆果内坏死病毒侵染的‘贝达'葡萄cDNA文库构建及其利用

 葡萄浆果内坏死病毒(grapevine berry inner necrosis virus, GINV)侵染葡萄可引起葡萄叶片表现明显的褪绿斑驳症状,其致病的分子机制,特别是病毒与寄主互作蛋白的研究尚未见报道。本研究构建了GINV侵染的‘贝达'葡萄叶片的cDNA文库,并以GINV 外壳蛋白(coat protein,CP)为诱饵筛选文库中与其互作的寄主因子。本研究构建的cDNA文库库容量达1.6×10⁷,插入片段平均大小在1.0 kb以上,质量符合cDNA文库筛库要求。筛选到了55个候选寄主蛋白与GINV CP在酵母中互作。经测序分析及回转验证,结果确定了17个寄主互作蛋白,其涉及叶绿体相关类蛋白、泛素化相关蛋白、防御相关蛋白等。本研究可为深入研究GINV致病性及其与寄主互作机制提供依据。     

大丽轮枝菌及激素处理后棉花酵母双杂交文库的构建

大丽轮枝菌是引起棉花、马铃薯等重要作物黄萎病的土传病原真菌,其分泌的胞外蛋白是侵染寄主的重要毒力因子,因此研究胞外蛋白与寄主的相互作用具有重要意义。本研究旨在构建高效的棉花酵母双杂交cDNA文库,并通过已知大丽轮枝菌效应子VCR1互作蛋白的筛选来评价构建文库的质量。分别采用大丽轮枝菌及茉莉酸甲酯、水杨酸和乙烯处理海岛棉‘海7124’以诱导其抗病基因表达,混合RNA样品构建酵母双杂交cDNA文库,文库滴度达1.18×10⁸ cfu/mL,检测重组率100%,插入片段在300~2000 bp之间。以效应子VCR1为诱饵筛选获得27个潜在互作蛋白,并进一步确证了1个与VCR1互作的靶标蛋白。本研究构建的酵母双杂交文库将为筛选与大丽轮枝菌效应子互作的蛋白及后续互作机理研究提供重要的研究基础。     

MNSV p42与寄主因子3-HIBADH互作

 甜瓜坏死斑点病毒(melon necrotic spot virus,MNSV)是侵染甜瓜的重要病毒之一,为害严重。为了明确MNSV的致病机制,本研究以pGBK-p42为诱饵载体,利用Mating的方法从感染MNSV的甜瓜cDNA文库中筛选出6个与p42互作的寄主因子,进一步利用酵母双杂交系统、双分子荧光互补技术(Bimolecular fluorescence complementation,BiFC)等验证p42与寄主因子3-羟基异丁酸脱氢酶(3-Hydroxyisobutyrate dehydrogenase-like 1, 3-HIBADH)的互作,并明确了p42 蛋白的s-domain是与3-HIBADH互作的关键区域。此外,利用激光共聚焦显微镜观察发现p42 s-domain与3-HIBADH作用改变了3-HIBADH蛋白在烟草表皮的亚细胞定位,进一步证实p42可与3-HIBADH发生相互作用。该结果为阐明甜瓜响应MNSV侵染的互作机制奠定了基础。     

基于小RNA深度测序技术鉴定侵染我国部分省市草莓种苗的病毒种类

随着草莓保护地栽培面积的增加和无性繁殖种苗的繁殖与调运,草莓病毒病的发生与流行日益严重。为明确侵染我国部分省市草莓种苗的病毒种类,应用小RNA深度测序技术进行检测,并利用RT-PCR技术对结果进行验证及序列分析。结果表明,从来自我国7省市的41株具有典型病毒病症状的草莓种苗样品中检测到草莓斑驳病毒strawberry mottle virus (SMoV)、草莓镶脉病毒strawberry vein banding virus(SVBV)和草莓轻型黄边病毒strawberry mild yellow edge virus (SMYEV)3种。SMoV、SVBV和SMYEV的检出率分别为34.1%、24.4%和2.4%。选取不同产地草莓种苗上检出的不同病毒进行部分序列测定和分析,获得了3个SMoV分离物(四川分离物schhy13、辽宁分离物lnhy23和河北分离物hbhy28)的部分RNA1 3′端非编码区606 bp核苷酸序列,其一致性为98.12%～99.34%。测定并获得了5个SVBV分离物(辽宁分离物lnhy15、lnhy17、lnhy24、河北分离物hbhy28和陕西分离物sh...     

西瓜噬酸菌不同菌株与甜瓜幼苗早期互作的转录组学分析

西瓜噬酸菌(Acidovorax citrulli)引起的瓜类细菌性果斑病(bacterial fruit blotch,BFB)是西瓜、甜瓜等葫芦科作物上毁灭性种传病害。本文利用RNA-seq技术,分析了2个西瓜噬酸菌菌株(pslb65和AAC00-1)分别诱导甜瓜感病品种IVF667幼苗6 h和12 h后的基因表达谱。结果表明,这2个菌株侵染寄主6 h后,分别检测到1 029和3 561个差异表达基因,其中上调基因分别为355和1 621个,下调基因分别为674和1 940个;与寄主互作12 h后,差异基因分别有2 397和1 875个,上调基因分别为903和898个,下调基因分别为1 494和977个。GO功能注释发现,pslb65与甜瓜幼苗互作的差异基因显著富集在生物学过程中的发育和代谢2个亚类,所占比例分别为32.92%和35.36%。在分子功能中转录因子所占比例较大,达到67.65%;AAC00-1与甜瓜幼苗互作后,差异基因显著富集在生物学过程中的转运和定位中,比例分别为23.84%和24.18%。在分子功能中氧化还原酶活性亚类所占比例高达17.59%。西瓜噬酸菌pslb65和AAC00-1侵染寄主6 h,Rboh、CaMCML、CDPK和FLS2等编码基因在植物-病原互作途径(csv04626)多为下调表达,植物-病原互作途径被抑制;12 h,pslb65-甜瓜互作途径相关基因多下调,AAC00-1-甜瓜互作途径相关基因多上调,推测此时植物-病原互作途径被AAC00-1激活,引起寄主的防御反应。西瓜噬酸菌pslb65和AAC00-1均可诱导植物发病,但在引起植物感病途径上略有不同,这可能与它们来自西瓜噬酸菌的不同亚群有关。最后,选取pslb65与寄主互作途径的6个基因进行qRT-PCR验证,结果与转录组测序结果基本一致。本研究初步揭示了西瓜噬酸菌2个不同菌株与寄主互作在转录水平上的表达差异,为研究甜瓜与不同菌株的互作机制差异奠定了基础。     

用酵母双杂交筛选与南瓜蚜传黄化病毒MP互作的寄主因子

植物病毒编码的移动蛋白(movement protein,MP)介导病毒在寄主体内的移动,研究其与寄主间的分子互作有助于揭示病毒侵染过程中的分子机制。将南瓜蚜传黄化病毒Cucurbit aphid-borne yellows virus(CABYV)MP基因定向克隆到含有DNA结合功能域(DNA-binding domain,BD)载体上,并构建与激活功能域(activation domain,AD)融合表达的西瓜茎叶cDNA文库,然后用MP为诱饵筛选文库寻找与其互作的寄主因子。结果表明,诱饵质粒插入的MP基因可读框和氨基酸序列均正确,对酵母菌株AH109和Y187没有自主激活能力;文库滴度为2.94×106CFU/mL,且大多数插入片段在700bp以上,质量符合筛选要求;经过筛选和共转化回转验证,有48个候选阳性克隆与MP在酵母中互作。测序得到这些克隆的cDNA序列,BLAST分析结果表明,这些克隆共编码12种蛋白。     

草莓镶脉病毒ORF Ⅵ基因的原核表达与抗血清制备

为了分析草莓镶脉病毒（Strawberry vein banding virus,SVBV）ORF Ⅵ基因的功能,采用原核表达技术获得该基因表达的重组蛋白并制备其抗血清。利用PCR技术扩增得到SVBV中国分离物的ORF Ⅵ基因,将此基因克隆到原核表达载体pET-SUMO上,获得重组质粒pET-SUMO-ORF Ⅵ。转化大肠杆菌BL21（DE3）后,经IPTG诱导与Ni²⁺-NTA亲和柱纯化,获得分子质量约为90 kD的重组蛋白。以纯化的重组蛋白为抗原免疫家兔制备抗血清,采用间接ELISA和Western blot方法测定抗血清的效价、反应灵敏度以及ORF Ⅵ基因在本氏烟中的瞬时表达。结果显示,间接ELISA法测定抗血清对重组蛋白的效价达1：256 000,Western blot法能够检测到稀释64 000倍的重组蛋白。利用稀释2 000倍的抗血清,仍能够检测出SVBV中国分离物和美国分离物ORF Ⅵ基因在本氏烟中瞬时表达的蛋白。     

筛选与黄瓜花叶病毒CP互作的寄主因子

黄瓜花叶病毒外壳蛋白是病毒最重要的致病因子。在病毒的侵染过程中扮演多种角色,尤其是对病毒侵染症状起了决定作用。本研究首先构建了烟草叶片c DNA文库,并将CP构建到酵母双杂交诱饵质粒上,利用酵母双杂交的方法筛选出与CP互作的寄主因子。结果显示,获得了高质量的烟草c DNA文库,并利用该文库筛选到与CP互作的多个潜在因子。     

草莓镶脉病毒ORF I基因的克隆、原核表达及抗血清制备

The total DNA was extracted from strawberry leaves infected with Strawberry vein banding virus (SVBV) by CTAB method. Specific primer pairs were designed to amplify the gene ORF I of SVBV-Shenyang isolate by PCR, gene ORF I was cloned into modified prokaryotic expression vector pET-32a (+)-GST, the recombinant plasmid pET-ORF I was transformed into E. coli DH5α, then the positive clones were screened and sequenced. The recombinant plasmid was extracted and transformed into Escherichia coli BL2l (DE3), the fusion protein with an approximate molecular weight of 56 kDa was obtained with IPTG induction and Ni²⁺-NTA affinity column purification. The purified fusion protein was used to immunize the rabbits to prepare the specific antiserum. The result of ELISA showed that the titer of the prepared antiserum is up to 1:520 000, Western blot analysis indicated that the prepared antiserum could reacted specifically with purified recombinant fusion protein. Not only the expression of P1 protein in SVBV infected-strawberry leaves, but also the expression of P1 protein in P1-infiltrated Nicotiana benthamiana leaves could be detected, using 2 000 times diluted antiserum.     

草莓镶脉病毒ORF I基因的克隆、原核表达及抗血清制备

The total DNA was extracted from strawberry leaves infected with Strawberry vein banding virus (SVBV) by CTAB method. Specific primer pairs were designed to amplify the gene ORF I of SVBV-Shenyang isolate by PCR, gene ORF I was cloned into modified prokaryotic expression vector pET-32a (+)-GST, the recombinant plasmid pET-ORF I was transformed into E. coli DH5α, then the positive clones were screened and sequenced. The recombinant plasmid was extracted and transformed into Escherichia coli BL2l (DE3), the fusion protein with an approximate molecular weight of 56 kDa was obtained with IPTG induction and Ni²⁺-NTA affinity column purification. The purified fusion protein was used to immunize the rabbits to prepare the specific antiserum. The result of ELISA showed that the titer of the prepared antiserum is up to 1:520 000, Western blot analysis indicated that the prepared antiserum could reacted specifically with purified recombinant fusion protein. Not only the expression of P1 protein in SVBV infected-strawberry leaves, but also the expression of P1 protein in P1-infiltrated Nicotiana benthamiana leaves could be detected, using 2 000 times diluted antiserum.     

利用多重RT-PCR技术检测草莓病毒的研究

 目前已报道侵染草莓的病毒有20多种,其中草莓斑驳病毒(Strawberry mottle virus, SMoV)、草莓轻型黄边病毒(Strawberry mild yellow edge virus, SMYEV)和草莓镶脉病毒(Strawberry vein banding virus, SVBV)是分布较广、危害较重的3种主要病毒。     

我国草莓主栽区病毒种类的鉴定

 病毒种类鉴定结果表明我国草莓主要栽培区存在草莓斑驳病毒、草莓轻型黄边病毒、草莓镶脉病毒和草莓皱缩病毒。四种病毒的总侵染株率达80.2%,其中单种病毒侵染株率为41.6%,两种或两种以上病毒复合侵染株率为38.6%。前三种病毒均为球状病毒,粒体直径分别为25-30nm、23nm和50nm;皱缩病毒为杆状病毒,大小为380×70nm。传染性试验的结果证实,草莓病毒可通过嫁接、菟丝子传染,但不能通过机械传染。桃蚜可传染斑驳病毒和轻型黄边病毒,其传毒关系前者为非持久性后者为持久性。田间桃蚜蚜虫口密度高峰期与草莓病毒侵染盛期相吻合。     

Real-time NASBA for Detection of Strawberry Vein Banding Virus

An assay for the detection of Strawberry vein banding virus (SVBV) in Fragaria spp. based on nucleic acid sequence based amplification (NASBA) and real-time detection using molecular beacons (real-time NASBA) is described. This assay was compared both with biological indexing, the current method for certification of SVBV, and a newly optimised PCR-based detection method. Performance of the assay was tested on three SVBV isolates in Fragaria indicator plants and 317 field strawberries from five European countries. The assay was shown to be SVBV-specific, testing negative for other common aphid-borne strawberry viruses. The virus was detected in purified total RNA preparations diluted a millionfold, which is an amount equivalent to 1ng of fresh material. The real-time NASBA method developed here offers the potential of a fast, sensitive and reliable approach for the routine diagnosis of strawberry stock material.     

利用酵母双杂交筛选与小麦黄花叶病毒P1互作的寄主蛋白

正小麦黄花叶病是我国冬小麦上重要的病毒病害之一,自20世纪90年代以来,每年发生面积都在66万hm~2以上,一般减产10%~30%,严重的达70%以上。该病害在我国河南、江苏、山东、安徽、陕西、湖北、四川等省均有分布,并且呈逐年蔓延趋     

Occurrence of aphidborne viruses in southernmost South American populations of Fragaria chiloensis ssp. chiloensis

Wild and cultivated Fragaria chiloensis ssp. chiloensis (Fcc) plants were collected at different locations in southern Chile in order to determine the current viral status of this native strawberry. The following aphidborne viruses (ABVs): Strawberry mild yellow edge virus (SMYEV), Strawberry mottle virus (SMoV), Strawberry crinkle virus (SCV) and Strawberry vein banding virus (SVBV), were found in wild and cultivated Fcc plants, but severe symptoms were not associated with viral infection. Furthermore, partial gene sequences of these ABV isolates were determined and displayed a high degree of conservation with virus isolates reported previously. In addition, partial gene sequences of SCV and SVBV from southernmost South American populations of Fcc are described for the first time. High‐throughput parallel sequencing (Illumina) of double‐stranded RNA was used to provide viral profiles of Fcc from different locations. Although strong evidence of novel viruses affecting Fcc was not found, it was confirmed that ABVs are the most frequent viruses affecting this subspecies. The information provided will help in the development of high‐quality molecular tools for virus detection and control in Fcc.