Development of Genetic Resources to Dissect Gene Regulatory Networks Governing Nodule Development and Differentiation in Medicago Truncatula

PI: Michael Udvardi (Samuel Roberts Noble Foundation, Inc.)CoPIs: Rujin Chen和Kirankumar Mysore （Samuel Roberts Noble Foundation, Inc.）豆类对人类农业的重要性仅次于草类。几千年来，豆科植物一直是农业系统不可或缺的一部分，对今天的可持续农业仍然很重要，因为它们可以与一种叫做根瘤菌的固氮细菌建立共生关系，为寄主植物提供减少的氮。这意味着豆科植物可以在含少量或不含无机氮或有机氮的土壤中生长，而不需要添加经济上和环境上昂贵的工业氮肥。豆科植物的共生固氮发生在与土壤中的根瘤菌接触后由根细胞发育的特殊器官中。根瘤菌在分化成一种称为类杆菌的固氮形式之前，在发育中的根瘤中定植植物细胞。豆科植物结节和类杆菌的发育和分化涉及数千种植物和细菌基因表达的协调变化。虽然最近我们对豆科植物与根瘤菌相互作用早期阶段植物-微生物信号传导的理解取得了巨大进展，但对于植物如何调节支撑根瘤发育和分化的基因表达的巨大变化，我们知之甚少。本项目旨在利用先进的基因表达谱技术，开发tnt1插入和快中子轰击（FNB）缺失突变群体，以鉴定在植物根瘤发育和分化过程中重新编程细胞的调控基因。该项目将特别关注转录因子和miRNA基因，这两类基因已知在植物基因表达的转录和转录后调控中起主导作用。项目过程中产生的微阵列数据将通过项目网站GEO和豆类信息服务（LIS; www.comparative-legumes.org）提供。侧翼序列数据和生物资源可通过项目网站LIS、Medicago基因组计划网站（www.medicago.org/genome）获取，或直接联系项目高级人员和/或生物资源馆长温江奇博士（jwen@noble.org）。该研究本质上是跨学科的，需要将基因组学、功能基因组学和生物信息学与遗传学、分子和细胞生物学以及植物生理学等更经典的学科相结合。通过在诺布尔基金会提供一个单一的培训基地，该项目将使博士后研究员、学生和技术人员能够学习许多对前沿生物学研究至关重要的研究技能。该项目还将参与诺贝尔基金会强大的学生外展计划，以最大限度地提高教学成果。最后，该项目将利用现有的国内和国际合作，加强美国、欧洲和澳大利亚科学家之间的联系。

PI: Michael Udvardi (Samuel Roberts Noble Foundation, Inc.)CoPIs: Rujin Chen and Kirankumar Mysore (Samuel Roberts Noble Foundation, Inc.)Legumes are second only to grasses in importance to humans for agriculture. Legumes have been an integral part of agricultural systems for thousands of years, and remain important for sustainable agriculture today because they can establish symbioses with nitrogen-fixing bacteria called rhizobia that supply their host plant with reduced nitrogen. This means that legumes can grow in soils containing little or no mineral or organic nitrogen, without the need to add economically and environmentally-expensive industrial nitrogen fertilizers. Symbiotic nitrogen fixation in legumes takes place in specialized organs that develop from root cells following contact with rhizobia in the soil. Rhizobia colonize plant cells in the developing nodules before differentiating into a nitrogen-fixing form called the bacteroid. Development and differentiation of legume nodules and bacteroids involve coordinated changes in the expression of thousands of plant and bacterial genes. While tremendous advances have been made recently in our understanding of plant-microbe signaling during the early stages of the legume-rhizobia interaction, little is known about how the plant regulates the massive changes in gene expression that underpin nodule development and differentiation. This project aims to use cutting-edge gene expression-profiling technology and to develop Tnt1-insertion and Fast Neutron Bombardment (FNB)-deletion mutant populations to identify regulatory genes that re-program plant cells during nodule development and differentiation. The project will focus, in particular, on transcription factor and miRNA genes, two classes of genes that are known to play leading roles in transcriptional and post-transcriptional regulation of gene expression in plants. Microarray data generated in the course of this project will be available through a project web site, GEO, and the Legume Information Service (LIS; www.comparative-legumes.org). Flanking sequence data and biological resources can be accessed via the project web site, LIS, the Medicago Genome Project website (www.medicago.org/genome), or by directly contacting project senior personnel and/or the curator of Biological Resources, Dr. Jiangqi Wen (jwen@noble.org). The research is trans-disciplinary in nature and requires the application of genomics, functional genomics, and bioinformatics with the more classical disciplines of genetics, molecular and cell biology, and plant physiology. By providing a single training ground at the Noble Foundation, this project will empower postdoctoral fellows, students, and technical staff to learn many of the research skills that are essential for cutting-edge biological research. This project will also participate in the Noble Foundation's strong student outreach program to maximize teaching and learning outcomes. Finally, the project will take advantage of existing domestic and international collaborations to strengthen links between scientists in the USA, Europe, and Australia.