Mutant-assisted exploration of natural variation underlying R gene-mediated immunity in maize

PI：Gurmukh（Guri）S. Johal，普渡大学合作伙伴：Clifford F. Weil，Purdue大学Co-PI：James. W. Moyer，北卡罗来纳州州立大学合作研究者：Peter J. Balint-Kurti，北卡罗来纳州州立大学植物抗病（R）基因编码的蛋白质通过触发快速、局部的“过敏反应”（HR）对病原体入侵作出反应，在这种反应中，紧邻感染部位的宿主组织经历程序性细胞死亡。尽管HR是植物免疫反应的基本组成部分，但对触发、发出信号、执行和包含它的基因知之甚少。在拟南芥中进行了详尽的诱变筛选，但只发现了少数与HR相关的基因，这可能是因为HR突变体的遗传冗余或致死性。一个替代的和潜在的巨大资源的人力资源变化是在天然种质。 如果有效地挖掘和划定，这一资源有可能大大提高我们对人力资源的理解。通过利用Rp 1基因的组成型活性等位基因，该基因赋予对玉米常见锈病的抗性，我们已经证明玉米种质含有大量能够影响HR的变异。该项目将测试创新方法的广泛使用，它寻找抑制突变表型的自然发生的等位基因，以快速检测和探索HR背后的自然变异。通过这种方法，一个HR调节基因座（Hrml 1）已经在使用玉米的IBM群体的初步测试中被鉴定和定位;该QTL将被克隆。 此外，更多的QTL将被确定和扩大屏幕的特点，目前可用于玉米社区的5000线巢式关联作图（NAM）人口。该项目的广泛影响是多方面的。 首先，发现和利用遗传多样性的方法可能广泛适用于大多数植物物种的大量重要性状。第二，外联部分将把生物多样性的利用纳入中学课程（6-8年级），并将DNA序列分析和数量性状分析纳入高中课程，同时编写和测试可广泛分发的教材。 第三，这些教学单元将为来自各种文化、种族和教育背景的学生及其教师开发，并与他们一起开发。 这一方法将允许使用不同的例子、不同的评估和不同的介绍形式，开发这些模块的几个版本，以便在各种情况下有效应用。 我们的目标是推翻刻板印象，这些科目太复杂，初中和高中学生掌握，并准备学生调查植物多样性和遗传学更详细地在以后的教育，使他们能够更好地理解这些问题。 尽管这些主题在科学和社会方面的重要性日益增加，但这些主题在这些级别的大多数科学课程中一般不包括在内。该项目产生的成果和生物资源将通过项目网站http://www.Rp1-MAGIC.purdue.edu提供。

PI: Gurmukh (Guri) S. Johal, Purdue UniversityCo-PI: Clifford F. Weil, Purdue UniversityCo-PI: James. W. Moyer, North Carolina State UniversityCo-PI: Peter J. Balint-Kurti, North Carolina State UniversityPlant disease resistance (R) genes encode proteins that respond to pathogen invasion by triggering a rapid, localized "hypersensitive reaction" (HR), in which host tissue immediately adjacent to the site of infection undergoes programmed cell death. Although, HR is a fundamental part of the immune response in plants, very little is known about the genes that trigger, signal, execute, and then contain it. Exhaustive mutagenesis screens have been conducted in Arabidopsis, but have turned up only a few genes linked to HR, possibly because of genetic redundancy or lethality of HR mutants. An alternate and potentially huge resource of HR variation is available in natural germplasm. If effectively tapped and delineated, this resource has the potential to advance considerably our understanding of HR . By taking advantage of a constitutive-active allele of the Rp1 gene, which confers resistance to the common rust disease of maize, we have demonstrated that the maize germplasm contains vast amounts of variation capable of impacting HR. This project will test the broad use of an innovative approach, which looks for naturally occurring alleles that suppress mutant phenotypes to rapidly detect and explore natural variation underlying HR. Using this approach, one HR-modulating locus (Hrml1) has already been identified and mapped in a preliminary test using the IBM population of maize; this QTL will be cloned. In addition, many more QTL will be identified and characterized by broadening the screen to the 5000-line Nested Association Mapping (NAM) population currently available to the maize community. The broader impacts of the project are many-fold. First, the approach of discovering and harnessing genetic diversity is likely to be broadly applicable to a large number of important traits in most plant species. Second, an outreach component will bring the uses of biodiversity to middle school curricula (Grades 6-8) and the topics of DNA sequence analysis and quantitative trait analysis to high school curricula, with the development and test of teaching materials that can be widely distributed. Third, these teaching modules will be developed for and with students from a wide range of cultural, racial and educational backgrounds, and their teachers. This approach will allow development of several versions of these modules, using different examples, different assessments and different forms of presentation so that they can be applied effectively in a variety of settings. The goal is to overturn the stereotype that these subjects are too complex for middle and high school students to grasp, and to prime student to investigate plant diversity and genetics in greater detail later in their education so that they are better able to understand the issues. These topics are not generally covered in most science curricula at these levels, despite their increasing importance scientifically and socially. The outcomes and biological resources generated by this project will be available through the project website: http://www.Rp1-MAGIC.purdue.edu.