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Cell-specific reprogramming of legume roots for endosymbiotic infection

豆科植物根的细胞特异性重编程以实现内共生感染

基本信息

批准号：
258665719
负责人：
Professor Dr. Martin Parniske
金额：
--
依托单位：
Institut für Genetik
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2014
资助国家：
德国
起止时间：
2013-12-31 至 2018-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/258665719?language=en
关键词：
Cell specific reprogramming legume roots

项目摘要

The vast majority of land plants can establish arbuscular mycorrhiza (AM), an agronomically important symbiosis with fungi to improve mineral and water supply. Legumes use an ancient signal transduction program, co-opted from the ancestral AM, to establish intracellular (endosymbiotic) interactions with nitrogen-fixing rhizobia, in the root nodule symbiosis. Successful symbiotic infection relies on an ancient cellular differentiation program for the intracellular accommodation of the microsymbionts. Although a number of important symbiosis genes essential for the infection process have been identified through genetic approaches, the precise cellular and molecular events underlying bacterial colonization of the root are poorly understood. The COME-IN project will focus on nuclear signalling events and associated transcriptional reprogramming that take place in host cells engaged in rhizobial infection. By developing cutting-edge cell imaging strategies in living cells, the Toulouse team has recently shown that calcium-spiking and the localized accumulation of the symbiotic ERF transcription factor (TF) ERN1 are specific nuclear responses which are associated with the early stages of infection. By pushing the technologies one step further, this project aims to decipher the spatio-temporal interconnection between calcium-spiking and the dynamics of TF accumulation and complex conformation preceding host cell transcriptional reprogramming for infection. We will focus on the two key infection-related TFs ERN1 and CYCLOPS, the latter acting in a complex with CCaMK, an important early integrator of calcium signalling. The Munich team has observed that CYCLOPS phosphorylation is essential for its transcriptional activity, and is associated with structural alterations of the CYCLOPS dimer. FRET-based strategies will be used to follow CYCLOPS complex formation in living cells during infection and how this correlates with calcium signalling. The Munich team has found the CYCLOPS promoter to be critical for successful symbiotic signalling. We will identify the cis- and trans-acting factors that determine the complex expression pattern of CYCLOPS. We will employ the INTACT (Isolation of Nuclei TAgged in specific Cell Types) technology to specifically target the small subpopulation of cells undergoing reprogramming and couple it with RNA sequencing to access gene transcription networks specifically associated with early stages of rhizobial infection. The comparison of cell-specific transcriptomes of wild type and infection-deficient mutants will aid in the identification of genes directly related to endosymbiotic entry. The COME-IN project will thus provide new insights into the cellular reprogramming during endosymbiotic root colonization.

绝大多数陆地植物可以建立丛枝菌根（AM），这是一种重要的农学共生体，与真菌共生，以改善矿物质和水分供应。豆科植物利用一个古老的信号转导程序，从祖先的AM增选，建立细胞内（内共生）的相互作用与固氮根瘤菌，在根瘤共生。成功的共生感染依赖于一个古老的细胞分化程序的微共生体的细胞内住宿。虽然一些重要的共生基因的感染过程中必不可少的已被确定通过遗传方法，精确的细胞和分子事件的基础上的细菌定植的根知之甚少。COME-IN项目将重点关注参与根瘤菌感染的宿主细胞中发生的核信号事件和相关的转录重编程。通过在活细胞中开发尖端的细胞成像策略，图卢兹团队最近表明，钙尖峰和共生ERF转录因子（TF）ERN 1的局部积累是与感染早期阶段相关的特异性核反应。通过进一步推动技术，该项目旨在破译钙尖峰和TF积累的动态和复杂构象之前的宿主细胞转录重编程感染之间的时空互连。我们将重点关注两个关键的感染相关的转录因子ERN 1和CYCLOPS，后者与钙信号传导的重要早期整合剂CCaMK复合。慕尼黑研究小组观察到CYCLOPS磷酸化对其转录活性至关重要，并与CYCLOPS二聚体的结构改变有关。基于FRET的策略将用于跟踪感染期间活细胞中CYCLOPS复合物的形成以及这与钙信号传导的相关性。慕尼黑研究小组发现CYCLOPS启动子对成功的共生信号传导至关重要。我们将确定决定CYCLOPS复杂表达模式的顺式和反式作用因子。我们将采用INTACT（特定细胞类型中标记的细胞核分离）技术来专门针对正在进行重编程的小细胞亚群，并将其与RNA测序结合起来，以访问与根瘤菌感染早期阶段特异性相关的基因转录网络。野生型和感染缺陷突变体的细胞特异性转录组的比较将有助于鉴定与内共生体进入直接相关的基因。因此，COME-IN项目将为内共生根定殖过程中的细胞重编程提供新的见解。