Sequencing the Gene Space of the Model Legume, Medicago Truncatula

对模型豆科植物——蒺藜苜蓿（Medicago Truncatula）的基因空间进行测序

• 批准号: 0321460
• 负责人: Nevin Young
• 金额: $ 1088.64万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Cooperative Agreement
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-10-01 至 2006-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0321460&HistoricalAwards=false
• 关键词: Sequencing; Gene; Space; Model; Legume

With more than 20,000 species, legumes are one of the two most important crop families in the world. Among cultivated plants, legumes are unique in their ability to fix atmospheric nitrogen through symbiosis with bacteria known as Rhizobia. Since they are not limited for nitrogen, legumes have remarkably high levels of protein, a property that is both biologically and agriculturally significant. Nearly 33% of all nutritional nitrogen comes from legumes, and legumes are the single most important source of nutritional protein throughout the developing world. Legumes also synthesize an impressive array of secondary compounds with anti-cancer and health promoting effects. Not surprisingly, legumes play a central role in nearly all cropping systems and are universally viewed as essential for secure and sustainable food production.Among legumes, Medicago (Medicago truncatula), a species closely related to alfalfa, is widely considered the preeminent model for genomic research. Medicago has a compact genome of approximately 470 million base pairs, simple Mendelian genetics, short generation time, relatively high transformation efficiency, and extensive collections of phenotypic mutants and naturally occurring ecotypes. Excellent cytogenetic research demonstrates that the Medicago genome is organized into separate gene-rich and gene-poor regions.Indeed, gene density in the gene-rich portions of the Medicago genome is nearly as high as in Arabidopsis. Thus, the Medicago genome is favorably organized for genome sequencing likely to capture nearly all of its gene-space.To sequence the gene-space of Medicago, a group of U.S. laboratories will completely sequence the gene-rich regions of six of Medicago's eight chromosomes. This work will be closely coordinated with colleagues in the European Union, who will sequence the gene-space of the remaining two Medicago chromosomes. In the process, sequences likely to contain genes will be identified and this information will be integrated with existing genomic information about Medicago. The most important beneficiaries of the Medicago genome sequence will be legume researchers - from genomicists to breeders - who will finally have a reference genome sequence representing most legume-specific properties. With the Medicago sequence in hand, detailed studies of legume-specific gene families, developmental processes, and biochemical pathways, gene cloning based on comparative genomics, discovery of pan-legume genetic markers - plus a genomic system ideally positioned for evolutionary comparison with Arabidopsis - will be available to researchers.

豆科植物有2万多种，是世界上最重要的两大作物科之一。在栽培植物中，豆科植物通过与根瘤菌共生来固定大气氮的能力是独一无二的。由于它们不局限于氮，豆科植物的蛋白质含量非常高，这一特性在生物学和农业上都很重要。近33%的营养氮来自豆类，豆类是发展中国家最重要的营养蛋白质来源。豆类还能合成一系列令人印象深刻的具有抗癌和促进健康作用的次级化合物。毫不奇怪，豆类在几乎所有的种植系统中都发挥着核心作用，并被普遍认为是安全和可持续粮食生产的关键。在豆科植物中，紫花苜蓿（Medicago truncatula）是一种与苜蓿密切相关的物种，被广泛认为是基因组研究的卓越模型。紫花苜蓿基因组紧凑，约4.7亿碱基对，简单的孟德尔遗传，代时间短，转化效率相对较高，广泛收集表型突变和自然发生的生态型。优秀的细胞遗传学研究表明，紫花苜蓿基因组被组织成单独的基因丰富和基因贫乏的区域。事实上，Medicago基因组中富含基因的部分的基因密度几乎和拟南芥一样高。因此，Medicago基因组是有利组织的基因组测序可能捕获几乎所有的基因空间。为了对Medicago的基因空间进行测序，一组美国实验室将对Medicago 8条染色体中的6条基因丰富区域进行完整测序。这项工作将与欧盟的同事密切协调，他们将对剩余的两条紫花苜蓿染色体的基因空间进行测序。在这个过程中，可能包含基因的序列将被识别出来，这些信息将与现有的关于紫花苜蓿的基因组信息相结合。Medicago基因组序列最重要的受益者将是豆类研究人员——从基因组学家到育种家——他们将最终获得一个代表大多数豆类特定特性的参考基因组序列。随着Medicago序列的掌握，豆科植物特异性基因家族、发育过程和生化途径的详细研究、基于比较基因组学的基因克隆、泛豆科植物遗传标记的发现——以及与拟南芥进行进化比较的理想定位的基因组系统——将为研究人员提供。