Functional Genomics of Plant Polyploids

植物多倍体的功能基因组学

• 批准号: 0077774
• 负责人: Shawn Kaeppler
• 金额: $ 499.69万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Cooperative Agreement
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-01 至 2006-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0077774&HistoricalAwards=false
• 关键词: Functional; Genomics; Plant; Polyploids

Polyploidy has played a prominent role in plant evolution. More than 70% of flowering plants have had at least one polyploid event in their lineage, either by doubling of a single genome (autopolyploidy) or, more commonly, by combining two or more distinct but related genomes (allopolyploidy). Many important crop plants, such as alfalfa, canola, cotton, potato and wheat, are obvious polyploids, and others, such as maize, soybean, and cabbage, retain the vestiges of ancient polyploid events. Although the importance of polyploidy has been widely recognized, the reasons for its success are not fully understood. Genome redundancy may provide some selective advantage, both through interactions of the combined genomes causing novel patterns of gene expression and through genome changes causing functional divergence of duplicated genes. Thus, polyploidy does not merely result in additivity for all traits from the progenitors, but often produces novel phenotypes that are not present in the parents or exceed the range of the parents. This phenomenon is analogous to heterosis, in which hybrid genotypes often have phenotypes that exceed those of their inbred parents.Rapid progress in genomic research of model plants and important crops has prompted the assembly of this consortium to study functional genomics of plant polyploids. The consortium is aimed at uncovering molecular mechanisms responsible for the evolutionary success of plant polyploids and agricultural utilization of plant hybrids. The theme of the proposed research is to investigate changes in gene expression and genome structure in resynthesized and natural autopolyploids and/or allopolyploids of Arabidopsis, Brassica and maize. Gene expression changes will be assayed using mRNA display and EST microarrays. New microarrays of the genes identified in heterochromatic regions will be developed and used for gene expression assays in Arabidopsis and Brassica. Changes in methylation state, transposon activity, chromatin status, and chromosomal arrangements will be determined using a combination of molecular, biochemical, and cytological techniques. The diploids, autopolyploids, and allopolyploids of each plant system will be compared to determine the effects of polyploidy on gene expression and genome structure. Inbred and hybrid maize at different ploidy levels will be compared to determine the relative effects of ploidy and heterozygosity on gene expression. Early and advanced generation polyploids of Brassica will be compared to test for stabilization of changes in the generations after polyploid formation and whether these changes are concerted and mimic natural polyploids. These studies will provide a comprehensive survey of the gene expression and genome changes accompanying polyploid formation and evolution. Most importantly, they should reveal some of the major mechanisms giving rise to these changes, and illuminate our overall understanding of why polyploids have been so successful in nature and agriculture.Participants:Thomas C. Osborn, PI, University of WisconsinJames A. Birchler, Co-PI, University of MissouriZ. Jeffery Chen, Co-PI, Texas A & M UniversityLuca Comai, Co-PI, University of WashingtonRobert A. Martienssen, Co-PI, Cold Spring Harbor LaboratoryRebecca Doerge, Co-PI, Purdue University

多倍体在植物进化中发挥着重要作用。超过 70% 的开花植物在其谱系中至少有一个多倍体事件，要么是单个基因组加倍（同源多倍体），要么更常见的是，通过组合两个或多个不同但相关的基因组（异源多倍体）。许多重要的农作物，如苜蓿、油菜、棉花、马铃薯和小麦，都是明显的多倍体，而其他农作物，如玉米、大豆和卷心菜，保留了古代多倍体事件的痕迹。 尽管多倍体的重要性已被广泛认识，但其成功的原因尚不完全清楚。 基因组冗余可能提供一些选择性优势，既通过组合基因组的相互作用导致新的基因表达模式，又通过基因组变化导致重复基因的功能分歧。 因此，多倍体不仅导致祖细胞所有性状的加和性，而且常常产生亲本中不存在或超出亲本范围的新表型。 这种现象类似于杂种优势，其中杂种基因型往往具有超过其近交亲本的表型。模式植物和重要作物基因组研究的快速进展促使这个联盟聚集起来研究植物多倍体的功能基因组学。 该联盟旨在揭示植物多倍体进化成功和植物杂交种农业利用的分子机制。 拟议研究的主题是研究拟南芥、芸苔属和玉米的再合成和天然同源多倍体和/或异源多倍体中基因表达和基因组结构的变化。 将使用 mRNA 展示和 EST 微阵列来分析基因表达变化。 将开发异染色质区域中鉴定的新基因微阵列，并将其用于拟南芥和芸苔属植物的基因表达测定。 将结合分子、生物化学和细胞学技术来确定甲基化状态、转座子活性、染色质状态和染色体排列的变化。 将比较每个植物系统的二倍体、同源多倍体和异源多倍体，以确定多倍体对基因表达和基因组结构的影响。 将比较不同倍性水平的自交和杂交玉米，以确定倍性和杂合性对基因表达的相对影响。 将比较芸苔属的早期和晚期多倍体，以测试多倍体形成后各代变化的稳定性以及这些变化是否一致并模仿天然多倍体。 这些研究将对伴随多倍体形成和进化的基因表达和基因组变化进行全面调查。 最重要的是，它们应该揭示引起这些变化的一些主要机制，并阐明我们对多倍体为何在自然和农业中如此成功的整体理解。参与者：Thomas C. Osborn，PI，威斯康星大学 James A. Birchler，Co-PI，密苏里大学。 Jeffery Chen，德克萨斯农工大学联合研究员 Luca Comai，华盛顿大学联合研究员罗伯特 A. 马丁森，冷泉港实验室联合研究员Rebecca Doerge，普渡大学联合研究员