Functional and Comparative Genomics of Disease Resistance Gene Homologs

抗病基因同源物的功能和比较基因组学

• 批准号: 9975971
• 负责人: Richard Michelmore
• 金额: $ 253万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-10-01 至 2004-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9975971&HistoricalAwards=false
• 关键词: Functional; Comparative; Genomics; Disease; Resistance

Genes encoding NBS-LRR containing proteins are one of the most prevalent classes in plant genomes, comprising an estimated 1% of all genes in Arabidopsis and at least as many in rice. However, little is known of their function. Sequence motifs indicate that they act at the beginning of signaling pathways. The only demonstrated function for these genes is in disease or pest resistance, but they may also be involved in other aspects of plant biology including development and response to the environment. The objectives of this project are to complete a detailed functional analysis of NBS-LRR genes in Arabidopsis and a comparative analysis of representatives in maize and rice. Broad functional classes of NBS-LRR encoding genes will be established and the specific functions of a subset of these classes will be characterized. Genes induced by the action of NBS-LRR gene products will be identified. NBS-LRR encoding genes identified in the Arabidopsis genome sequencing project will be characterized in a high-throughput format using ligand-independent approaches involving either over-expression or gain-of-phenotype variants. Microarrays will be used to determine changes in global expression patterns caused by expression of NBS-LRR genes and will also look for gross developmental and physiological changes. The expression array data will provide an 'induced expression signature' for each gene that will indicate its function as well as allow them to be assigned into functional classes. The expression signature of known resistance genes, such as RPM1, RPS2 and RPP5, will be characterized and compared to the expression signatures of the unknown genes. Homologs representing each functional class identified in Arabidopsis will be studied in an analogous fashion in rice and maize. Homologs will be obtained from databases or amplified de novo using conserved oligonucleotide primers. Using parallel approaches to those employed for Arabidopsis, induced expression signatures for each homolog will be determined using diagnostic microarrays for rice and maize. These diagnostic arrays will be developed by selecting clones of cereal sequences available in the database using expression data from Arabidopsis plus other putative defense genes from each of these species. Each NBS-LRR homolog will be mapped onto the consensus genetic map for each species relative to a variety of phenotypes. This global approach will efficiently provide functional information on approximately 1% of the genes in the model plant, Arabidopsis, and will extend this information to two important crop species. The work will define the different classes of resistance genes and identify those with other functions; this will establish how many act as resistance genes and how many control processes unrelated to defense. It will also identify sets of downstream genes regulated by each class. This will provide the basis for detailed studies into the action of specific NBS-LRR and downstream genes. It will provide tools to facilitate the practical manipulation of plant disease resistance and may ultimately provide the ability to manipulate diverse aspects of plant development and physiology.

编码含有 NBS-LRR 的蛋白质的基因是植物基因组中最常见的类别之一，估计占拟南芥中所有基因的 1%，在水稻中也至少有同样多的基因。 然而，人们对它们的功能知之甚少。序列基序表明它们在信号传导途径的起始处起作用。这些基因唯一被证明的功能是抗病或害虫，但它们也可能涉及植物生物学的其他方面，包括发育和对环境的响应。该项目的目标是完成拟南芥中NBS-LRR基因的详细功能分析以及玉米和水稻中代表基因的比较分析。 将建立 NBS-LRR 编码基因的广泛功能类别，并对这些类别的子集的具体功能进行表征。 将鉴定由NBS-LRR基因产物的作用诱导的基因。 拟南芥基因组测序项目中鉴定的 NBS-LRR 编码基因将使用涉及过度表达或表型变异获得的配体独立方法以高通量形式进行表征。微阵列将用于确定由NBS-LRR基因表达引起的整体表达模式的变化，并且还将寻找总体发育和生理变化。 表达阵列数据将为每个基因提供“诱导表达签名”，该基因将指示其功能并允许将它们分配到功能类别中。 将表征已知抗性基因（例如 RPM1、RPS2 和 RPP5）的表达特征，并将其与未知基因的表达特征进行比较。代表拟南芥中鉴定的每个功能类别的同源物将以类似的方式在水稻和玉米中进行研究。 同源物将从数据库获得或使用保守寡核苷酸引物从头扩增。使用与拟南芥所采用的方法平行的方法，将使用水稻和玉米的诊断微阵列来确定每个同源物的诱导表达特征。 这些诊断阵列将通过使用拟南芥表达数据以及来自每个物种的其他推定防御基因选择数据库中可用的谷物序列克隆来开发。 每个 NBS-LRR 同源物将被映射到每个物种相对于各种表型的共有遗传图谱上。 这种全局方法将有效地提供模式植物拟南芥中大约 1% 的基因的功能信息，并将该信息扩展到两种重要的作物物种。 这项工作将定义不同类别的抗性基因，并鉴定那些具有其他功能的基因；这将确定有多少充当抗性基因以及有多少与防御无关的控制过程。它还将识别由每个类别调节的下游基因组。 这将为详细研究特定NBS-LRR和下游基因的作用提供基础。 它将提供促进植物抗病性的实际操作的工具，并最终可能提供操作植物发育和生理学各个方面的能力。