CAREER: Exploring the Transcriptional Regulatory Networks Controlling the Early Stages of Legume Nodulation

职业：探索控制豆科植物结瘤早期的转录调控网络

• 批准号: 1453613
• 负责人: Marc Libault
• 金额: $ 110万
• 依托单位: University of Oklahoma Norman Campus
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-15 至 2018-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1453613&HistoricalAwards=false
• 关键词: CAREER; Exploring; Transcriptional; Regulatory; Networks

A group of bacteria called rhizobia convert atmospheric nitrogen to a chemical form available to support growth and reproduction of plants in the legume family. The bacteria establish a symbiotic relationship with their legume hosts, residing in root nodules where specialized structures develop to facilitate the exchange of nutrients between the two partners. This is an economically important process as it reduces the amount of nitrogen fertilizer needed to grow crops and is a key component in sustainable agriculture. Thus, a better understanding of the molecular mechanisms controlling the nodulation process should lead to insights about more effective ways to capture and fix atmospheric nitrogen and to the transfer of this capacity to non-legume plants. One notable achievement in our understanding of legume nodulation is the characterization of the signaling steps that control the infection of the plant root hair cell by rhizobia, the initial step of nodulation. This symbiotic pathway is regulated by almost 2000 genes in legume root hair cells. The investigators will characterize a network of genes essential in controlling the early stages of nodulation. In addition to its impact on legume research, the broader impacts of this project include the development of unique educational programs dedicated to Oklahoma high-school and undergraduate students from under-represented groups, promoting strong integration between research and education.This CAREER project is built on the hypothesis that regulatory networks directly under the control of one or several transcription factors of the symbiotic pathway orchestrate the proper activation and timing of gene expression in root hair cells in response to rhizobia. Specifically focusing on the Nodulation Signaling Pathway1 (NSP1) regulatory network, this project will address two key questions: What is the identity of the soybean and medicago root hair genes directly under the control of NSP1? What are the protein complexes asscociated with NSP1 and how do they control the expression of root hair genes in response to rhizobial inoculation? To answer these questions, the investigators will 1) characterize the soybean root hair genes directly under the control of the transcription factors GmNSP1a and b in response to Bradyrhizobium japonicum through high-throughput sequencing technologies and by applying DamID-seq or ChIP-seq methods, 2) identify the protein partners of the GmNSP1a and b in root hair cells inoculated with B. japonicum by co-immunoprecipitation of the protein partners in root hair cells upon rhizobia inoculation; 3) validate the conservation of the root hair gene regulatory networks between soybean and Medicago truncatula, the model legume.

一群被称为根瘤菌的细菌将大气中的氮转化为一种可用于支持豆科植物生长和繁殖的化学形式。这种细菌与它们的豆科寄主建立了一种共生关系，它们居住在根瘤中，在根瘤中形成了专门的结构，以促进双方之间的营养交换。这是一个经济上重要的过程，因为它减少了种植作物所需的氮肥量，是可持续农业的关键组成部分。因此，更好地了解控制结瘤过程的分子机制，将有助于找到更有效的方法来捕获和固定大气中的氮，并将这种能力转移到非豆科植物中。在我们对豆科植物结瘤的理解中，一个显著的成就是对根瘤菌侵染植物根毛细胞的信号传导步骤的表征，根瘤菌侵染是根瘤形成的初始步骤。这一共生途径受豆科植物根毛细胞中近2000个基因的调控。研究人员将描述控制结瘤早期阶段必不可少的基因网络。除了对豆类研究的影响外，该项目更广泛的影响包括开发独特的教育项目，致力于俄克拉何马州高中和本科生来自代表性不足的群体，促进研究与教育之间的强大整合。这个CAREER项目是建立在这样一个假设之上的，即在共生途径的一个或几个转录因子的直接控制下，调控网络协调根毛细胞对根瘤菌的适当激活和基因表达的时间。本项目特别关注结瘤信号通路1 （NSP1）调控网络，将解决两个关键问题：NSP1直接控制的大豆和紫花苜蓿根毛基因的身份是什么？与NSP1相关的蛋白复合物是什么？它们如何控制根瘤菌接种后根毛基因的表达？为了回答这些问题，研究人员将1)通过高通量测序技术和DamID-seq或ChIP-seq方法，对转录因子GmNSP1a和b直接控制的大豆根毛基因进行特征鉴定；2)在根毛菌接种后，通过根毛细胞中蛋白伴侣的共免疫沉淀，鉴定接种日本芽孢杆菌的根毛细胞中GmNSP1a和b的蛋白伴侣；3)验证大豆与模式豆科植物苜蓿根毛基因调控网络的保守性。