CAREER: Virus Structure in Plant Resistance

;​R o o t E n t y F @ @ C o m p o b j b W o r d d o c u m e n t O b j e c t P O O l @ @​F Microsoft Word 6.0文档MSWordDoc。6;Oh +' 0 $ H l D H R:\WWUSER\TEMPLATE\NORMAL。DOT杰克科恩杰克科恩@ d @ @ B e = e d d d d d d d d d \ f d C p t t t t t t t t tT T T T T T T p T T T T T T。植物的抗病性由于其在农业上的重要经济意义而得到了广泛的研究。这方面的努力主要集中在单一植物基因赋予的超敏反应（HR）上。这种类型的抗性依赖于宿主对入侵病原体的识别，可能是通过植物受体特异性结合病原体来源的分子，称为激发子。近年来，一些植物抗性基因的克隆和鉴定是植物生物学领域的重大突破，并为激发子受体假说提供了新的支持。未来的研究确定病原体激发子和植物抗性基因之间的分子相互作用对于理解植物抗病的分子基础和开发在田间利用这种抗性的实际方法至关重要。以烟叶病毒外壳蛋白（CP）与烟叶N′基因HR的相互作用为模型系统，对激发子特异性进行分子表征。目前的证据表明，具有“较弱”的四元结构的CPs作为HR的激发子，而具有“较强”的四元结构的CPs则没有。确定HR诱导所需的结构基序将是确定推定的引发子受体相互作用的重要第一步。将解决三个目标：1)确定被N'基因宿主识别的CP的形式（单体，二聚体，三聚体等）；2)在CP三维结构中确定一个假定的受体结合位点；3)研究CP的结构改变，使某些乙型肝炎病毒能够避开N'基因抗性。该提案的一个重要方面是为本科生和研究生提供分子生物学和蛋白质生物物理学研究方面的培训。本研究涉及的广泛科学问题为对研究事业感兴趣的学生提供了理想的跨学科“训练矩阵”。学生将学习操作蛋白质序列所需的技能（基因克隆、位点特异性诱变等），确定这些操作的生物物理后果（分析超离心、圆二色性和电子显微镜），并将这些变化与生物功能（病毒粒子结构和植物抗性）联系起来。除了技术技能，学生们还将组织并在计划的年度小型会议上展示他们的研究成果。由于植物的抗病性在农业上具有重要的经济意义，因此得到了广泛的研究。这方面的努力主要集中在单一植物基因赋予的超敏反应（HR）上。这种类型的抗性依赖于宿主对入侵病原体的识别，可能是通过植物受体特异性结合病原体来源的分子，称为激发子。最近对几种植物抗性基因的克隆增加了对激发子受体假说的支持。以烟叶病毒外壳蛋白（CP）与烟叶N′基因HR的相互作用为模型系统，对激发子特异性进行分子表征。具体来说，是什么让一种病原体引发耐药性反应而另一种却没有？将解决三个目标：1)确定被N'基因宿主识别的CP的形式（单体，二聚体，三聚体等）；2,1在CP三维结构中鉴定和分析推测的受体结合位点；3)研究使某些乙型肝炎病毒避开N'基因抗性的CPs之间的结构差异。这项研究的信息对于了解植物抗病的分子基础和开发更充分利用这种抗性的实际方法具有重要意义。*** @ ....()()))()() ;如果我是你，我是你，我是你，我是你，我是你。

; R o o t E n t r y F @ @ C o m p O b j b W o r d D o c u m e n t O b j e c t P o o l @ @ F Microsoft Word 6.0 Document MSWordDoc Word.Document.6 ; Oh +' 0 $ H l D h R:\WWUSER\TEMPLATE\NORMAL.DOT jack cohen jack cohen @ d @ @ B e = e D D D D D \ f D C p t t t t t t t S D T ( t t t t t t t p t t t t t t . 6 t t / t Culver 9506849 Plant disease resistance has been widely studied because of its economic importance to agriculture. Much of this effort has focused on the hypersensitive response (HR) conferred by single plant genes. This type of resistance is dependent upon host recognition of the invading pathogen, possibly via plant receptors that specifically bind molecules of pathogen origin, called elicitors. The recent cloning and characterization of several plant resistance genes has been a major breakthrough in the field of plant biology and has added support to the elicitor receptor hypothesis. Future studies defining the molecular interaction between pathogen elicitors and plant resistance genes will be critical in understanding the molecular basis of plant disease resistance and in developing practical ways to utilize this resistance in the field. Using the interaction between the tobamovirus coat protein (CP) and the N' gene HR of Nicotiana sylvestris as a model system, this proposal seeks to molecularly characterize elicitor specificity. Current evidence indicates that CPs with "weaker" quaternary structures act as elicitors of the HR while CPs with "stronger" quaternary structures do not. Identifying the structural motifs required for HR induction will be an important first step in defining putative elicitor receptor interactions. Three objectives will be addressed: 1) identify the form (monomer, dimer, trimer, etc.) of CP that is recognized by the N' gene host; 2) identify a putative receptor binding site within the CP three dimensional structure; 3) investigate structural alterations in CP that allow some tobamoviruses to elude N' gene resistance. An important aspect of this proposal is to provide undergraduate and graduate students with training in both molecular biology and protein biophysical studies. The wide range of scientific matters involved in this investigation provide an ideal interdisciplinary "training matrix" for students interested in research careers. Students will learn the skills needed to manipulate protein sequences (gene cloning, site specific mutagenesis, etc.), determine the biophysical consequences of those manipulations (analytical ultracentrifugation, circular dichroism, and electron microscopy), and relate these changes to biological function (virion structure and plant resistance). In addition to technical skills, students will organize and present their research at a planned yearly miniconference. %%% Plant disease resistance has been widely studied because of its economic importance to agriculture. Much of this effort has focused on the hypersensitive response (HR) conferred by single plant genes. This type of resistance is dependent upon host recognition of the invading pathogen, p ossibly via plant receptors that specifically bind molecules of pathogen origin, called elicitors. The recent cloning of several plant resistance genes has added support to the elicitor receptor hypothesis. Using the interaction between the tobamovirus coat protein (CP) and the N' gene HR of Nicotiana sylvestris as a model system, this proposal seeks to molecularly characterize elicitor specificity. Specifically, what makes one pathogen elicit a resistance response while another does not? Three objectives will be addressed: 1) identify the form (monomer, dimer, trimer, etc.) of CP that is recognized by the N' gene host; 2,1 identify and analyze the putative receptor binding site within the CP three dimensional structure; 3) investigate the structural differences between CPs that allow some tobamoviruses to elude N' gene resistance. Information from this study will be important to understanding the molecular basis of plant disease resistance and in developing practical ways to more fully utilize this resistance in the field. *** @ ....()()))()() ; S u m m a r y I n f o r m a t i o n (