转基因植物中RNA介导病毒抗性

１９８６年以来,利用病毒外壳蛋白及其它基因转化植物,获得具抗病毒能力的植株,已有大量成功的报道。以前,一直认为是病原体来源的基因引发抗性,但在实验过程中,发现转基因植物中转化基因的表达水平与病毒抗性程度之间没有直接联系,因此有人提出转基因植物抗性获得与病毒ＲＮＡ特异性降解有关的机制。本文对ＲＮＡ介导抗性机制进行讨论     

转基因植物中RNA介导的病毒抗性研究进展

利用病毒核酸序列培育抗病毒的转基因植物是一个重要的抗病毒基因工程策略。虽然很多种病毒的不同核酸序列已被使用并证明转基因植物有不同程度的抗病毒效果,但其抗病机制大多不清楚。目前至少有两种明显不同的抗病机制类型：一种是要求病毒编码的蛋白质的表达;另一种是仅仅依靠转基因的ＴＮＡ转录。本文综述了这种ＲＮＡ介导的抗性特点、分子生物学、抗病机制,以及与共抑制的相似性,并对ＲＮＡ介导的病毒抗性的意义加以讨论。     

基因沉默

基因沉默 (ｇｅｎｅｓｉｌｅｎｃｉｎｇ)是指生物体中特定基因由于种种原因不表达。一方面 ,基因沉默是遗传修饰生物 (ｇｅｎｅｔｉｃａｌｌｙｍｏｄｉｆｉｅｄｏｒｇａｎｉｓｍｓ)实用化和商品化的巨大障碍 ,另一方面 ,基因沉默是植物抗病毒的一个本能反应 ,为用抗病毒基因植物工程育种提供了具有较大潜在实用价值的策略———ＲＮＡ介导的病毒抗性 (ＲＮＡ ｍｅｄｉａｔｅｄｖｉｒｕｓｒｅｓｉｓｔａｎｃｅ ,ＲＭＶＲ) [1～ 3] 。基因沉默现象首先在转基因植物中发现 ,接着在线虫、真菌、昆虫、原生动物以及老鼠中陆续发现。大量的研究表…     

植物抗病毒病育种策略

为了得到抗病毒的寄主植物,植物育种学家进行了许多有益研究,形成了许多行之有效的抗病毒病育种策略。利用植物本身对病毒侵染所具有的一些免疫功能及其本身的一些抗性基因来获得抗性;利用来源于病毒自身基因的一些抗病性策略(PDR),如利用病毒外壳蛋白基因,病毒复制酶基因,病毒移动蛋白基因,病毒卫星RNA和反义RNA等,植物也可以获得抗性。近年来对由转录后RNA沉默引起的由RNA介导的病毒抗性策略(RMVR)也进行了深入地研究。除了PDR和RMVR以外,还有一些导致植物抗病毒的策略,包括利用美国商陆的病毒抗性蛋白(PAP),2',5’-寡腺苷酸合成酶,“植物抗体”以及病毒蛋白多肽来获得病毒抗性等。     

兰花抗病毒基因工程研究进展(综述)

兰花病毒病严重影响兰花产业的发展,研究和探索防治兰花病毒病的新技术、新途径已成为众多研究者普遍关注的焦点。本文综述目前抗兰花病毒研究中应用的各种抗病毒基因工程策略,包括病毒来源基因中的外壳蛋白基因和运动蛋白基因介导的抗性策略,RNA介导的抗病毒策略,植物自身的抗病毒基因介导的抗性策略,利用多基因介导的抗性策略,以及抗体基因介导的抗性策略等。最后对兰花抗病毒基因工程的发展及应用进行了展望。     

植物病毒表达载体研究进展

利用ＤＮＡ或ＲＮＡ植物病毒作载体表达外源蛋白是几年发展较快的一种新的遗传转化方式,它具有以下几个优点,表达量大,表达速度快,地进行基因操作和接种以及适用对象广泛。已发展的四种载体构建策略包括：基因取代,基因插入,融合抗原和基因互补。植物病毒表达载体可以用于基因的重组、病毒的移动和基因功能的检测等基础性研究,也可用于商业上表达多种药用蛋白或疫苗,植物病毒表达载体的稳定性主要取决于存在同源序列而引起的     

植物基因工程进展

一、转基因植物和转化方法二、抗病毒的转基因植物(一)利用基因工程达到抗病毒的几种策略(二)利用病毒外壳蛋白的基因(三)病毒非结构蛋白基因介导的抗性三、抗虫转基因植物(一)预计可能的商品化时间表(二)关于修饰B。tCryIA,CryIA基因密码(三)多途径应用Bt杀虫蛋白基因(四)抗同翅目害虫转基因植物的突破。四。抗真菌性病害的转基因植物(一)抑制核糖体蛋白(二)几丁酶和葡聚糖酶五。抗细菌的转基因植物(一)利用病原细菌天然解毒能力(二)利用天然抗菌肽和溶菌酶六、结束语--简介植物基因工程在培育雄性不育株系,改良植物品质及植物生物反应器方面的应用,以及回顾和展望。     

果实成熟的基因工程研究

乙烯是催化果实成熟的内源植物激素。本文简要介绍用植物基因工程的手段分离和鉴定出乙烯合成和果实成熟有关的多聚半乳糖醛酸酶、ＡＣＣ氧化酶、ＡＣＣ合酶及ＡＣＣ脱氨酶的基因。并利用反意ＲＮＡ技术将它们的反意ＲＮＡ转入番茄中,得到了相应的反意转基因植株和果实,实现了在基因水平上对果实成熟的调控,开辟了植物育种的新途径。     

从带烟草花叶病毒外壳蛋白亚基因组启动子的负链RNA产生正链RNA

克隆了能在植物中表达白喉毒素Ａ链基因（ＤＴＡ）负链ＲＮＡ的基因ＴＣＤＴＡＮ,这个基因的读码框５′端上游带有ＴＭＶ外壳蛋白基因５′端上游６３１个碱基,它的ＤＮＡ和ＴＭＶ－ＲＮＡ共转化烟草原生质体后,能抑制同时导入原生持体的堪因的表达,ＣＡＴ基因表达的抑制,是ＴＣＤＴＡＮ基因产生白喉毒素Ａ链蛋白的结果,ＴＣＤＴＮＡ基因上ＴＭＶ外壳蛋白基因５′端上游片段,是产生白喉毒素Ａ链ｍＲＮＡ的必要条件,只有用多量     

Strategies for antiviral resistance in transgenic plants

Genetic engineering offers a means of incorporating new virus resistance traits into existing desirable plant cultivars. The initial attempts to create transgenes conferring virus resistance were based on the pathogen-derived resistance concept. The expression of the viral coat protein gene in transgenic plants was shown to induce protective effects similar to classical cross protection, and was therefore distinguished as 'coat-protein-mediated' protection. Since then, a large variety of viral sequences encoding structural and non-structural proteins were shown to confer resistance. Subsequently, non-coding viral RNA was shown to be a potential trigger for virus resistance in transgenic plants, which led to the discovery of a novel innate resistance in plants, RNA silencing. Apart from the majority of pathogen-derived resistance strategies, alternative strategies involving virus-specific antibodies have been successfully applied. In a separate section, efforts to combat viroids in transgenic plants are highlighted. In a final summarizing section, the potential risks involved in the introduction of transgenic crops and the specifics of the approaches used will be discussed.     

RNA干扰在植物中的作用机理及其应用研究进展

RNA干扰(RNAi)是广泛存在于生物中的一种现象,它是小干扰RNA诱导的转录后基因沉默,是生物抵抗异常DNA的一种保护机制,同时在生物生长发育过程中调控基因的表达.本文综述了近年来有关RNA干扰的发现、作用过程及其机理,分析了它与反义寡核苷酸、核酶、脱氧核酶的小同,并介绍了RNA干扰在植物基因功能、植物抗病毒、作物品种改良等方面的应用,为siRNA干扰的进一步利用提供参考资料.     

Antiviral strategies in plants based on RNA silencing

One of the challenges being faced in the twenty-first century is the biological control of plant viral infections. Among the different strategies to combat virus infections, those based on pathogen-derived resistance (PDR) are probably the most powerful approaches to confer virus resistance in plants. The application of the PDR concept not only revealed the existence of a previously unknown sequence-specific RNA-degradation mechanism in plants, but has also helped to design antiviral strategies to engineer viral resistant plants in the last 25 years. In this article, we review the different platforms related to RNA silencing that have been developed during this time to obtain plants resistant to viruses and illustrate examples of current applications of RNA silencing to protect crop plants against viral diseases of agronomic relevance. This article is part of a Special Issue entitled: MicroRNAs in viral gene regulation.     

The optimization of viral vector translation improves the production of recombinant proteins in plants

One of the most convenient methods for the fast and efficient production of target proteins in plants involves self-replicating recombinant viral vectors. We have constructed a plant viral vector based on the genome of the potato X virus. This vector contains the sequence of the 5′-untranslated region of RNA 4 of the alfalfa mosaic virus immediately upstream of the target gene. The incorporation of this sequence into the viral vector increases the production of the target protein by the recipient plant three- to fourfold owing to the increased efficiency of translation of viral subgenomic RNA comprising the target gene. The new vector can be used for the production of recombinant proteins in plants. Original Russian Text ? E.S. Mardanova, R.Yu. Kotlyarov, N.V. Ravin, 2009, published in Molekulyarnaya Biologiya, 2009, Vol. 43, No. 3, pp. 568–571.     

香蕉花叶病毒外壳蛋白基因克隆及表达载体的构建

从海南大田感染香蕉花叶病的香蕉叶片 ,获得香蕉花叶病毒 ,提纯其 RNA,在 AMV反转录酶作用下合成 c DNA第一链 ,经 PCR扩增 ,获得一约 70 0 bp的 DNA片段 ,测序结果显示所克隆的 DNA片段包含一完整的香蕉花叶病毒株系 ( CMV-BHI)外壳蛋白基因 ,长度为 6 5 7bp,然后将此 DNA片段 ,分别克隆到p BI1 2 1和 p KHG4质粒 ,构成两个含 Ca MV35 s启动子 ( 5 '-端 )、NOS终止子 ( 3'-端 )和分别含 NPT 标记基因和 NPT 及 HPT标记基因的植物表达载体 ( p TBB和 p TBK)。然后用 p AHC1 8中的 UBI promoter换下p BI1 2 1的 Ca MV35 s promoter,构成 p BIAH;再用 CMV-BHI外壳蛋白基因换下 p BIAH中 GUS基因 ,构成一含单子叶植物启动子 UBI和 NPT 标记基因的植物表达载体 ( p TBBU)。从而为 CMV-BHI外壳蛋白基因在香蕉中表达打下了基础     

Transgenic tobacco plants expressing the bacterial mc gene resist virus infection

A bacterial rnc gene coding for a double-stranded RNA-dependent RNase III endoribonuclease and a mutant, rnc70, were expressed in tobacco plants. The RNase III protein produced in the transgenic plants was the same size as the bacterial protein. Expression of the wild-type gene could cause stunting in some plant lines, but not in others. Expression of the mutant protein did not affect normal growth and development of the transgenic plants. Transgenic plants of the R1 and R2 generations, expressing the wild type, as well as a mutant protein, were resistant to infection by three disparate RNA plant viruses with a divided genome but not against two viruses with a single-stranded RNA genome. Introduction of the rnc gene in crop plants may provide resistance to economically important virus diseases.     

RNA interference and plant parasitic nematodes

RNA interference (RNAi) has recently been demonstrated in plant parasitic nematodes. It is a potentially powerful investigative tool for the genome-wide identification of gene function that should help improve our understanding of plant parasitic nematodes. RNAi should help identify gene and, hence, protein targets for nematode control strategies. Prospects for novel resistance depend on the plant generating an effective form of double-stranded RNA in the absence of an endogenous target gene without detriment to itself. These RNA molecules must then become available to the nematode and be capable of ingestion via its feeding tube. If these requirements can be met, crop resistance could be achieved by a plant delivering a dsRNA that targets a nematode gene and induces a lethal or highly damaging RNAi effect on the parasite.