Deciphering the transcriptional and molecular morpho-dynamic landscape controlling intracellular uptake of rhizobia

破译控制根瘤菌细胞内摄取的转录和分子形态动力学景观

• 批准号: 431626755
• 负责人: Professor Dr. Thomas Ott
• 金额: --
• 依托单位: National Natural Science Foundation of China
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2020
• 资助国家: 德国
• 起止时间: 2019-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/431626755?language=en
• 关键词: Deciphering; transcriptional; molecular; morpho; dynamic

The Rhizobium-legume symbiosis is one of the most advanced intracellular plant-microbe interaction and mainly involves mutualistic recognition, infection via infection threads (ITs) and rhizobial release into the host cells in root nodules. During these processes, extensive and coordinated changes in gene expression patterns and molecular morpho-dynamics, such as plasma membrane proliferation and formation of the peribacteriod membrane (PBM) occur. Understanding the transcriptional, molecular and cellular patterns at this critical stage of nodulation is essential to elucidate molecular regulatory networks that control rhizobia-host cell interaction and subsequent rhizobia-legume symbiotic nitrogen fixation. However, the transcriptional and molecular morpho-dynamic landscape controlling intracellular uptake of rhizobia remains largely uncharacterized. Previously, the Ott lab found that SYMREM1 physically interacts with Nod factor receptors and is required for IT growth and rhizobia release, indicating that SYMREM1 plays a specific role in rhizobial uptake at the earlier stage of nodulation of M. truncatula. The Li lab has identified GmSYMREM1 as the functional ortholog of MtSYMREM1 in G. max and validated the interaction between GmSYMREM1 and NFR1α/5α. The collaborative work between the Ott and Li lab has also shown that the induction of GmSYMREM1 by rhizobia is regulated by miR172-NNC1 module. These data suggest that both Medicago and soybean which are indeterminate and determinate nodulators, respectively, may share a conserved mechanism by which SYMREM1-mediated plasma membrane nanodomain controls rhizobial infection and release into the host cells during legumes-rhizobial symbiosis. This joint proposal will:1) expand and finalize our joint analysis on the transcriptional regulation of SYMREM1 genes; 2) use complementary approaches such as ChIP-seq and promoter evolution to identify our future targets; 3) adopt the approaches like single cell sequencing to map the epigenetic dynamics that modulate cell specification during nodulation; 4) use these promoters not only for engineering synthetic modules that allow precision targeting of proteins to the PBM but also unravel the transcription factor complex that regulates these modules; and 5) address morpho-dynamic processes with ultrastructural resolution using correlative microscopy and identify key factors that mediate bacterial release. This project will greatly advance our knowledge on mechanisms controlling intracellular uptake of rhizobia. We will uncover and distinguish general molecular mechanisms of PBM targeting of proteins, rhizobial release and host cell differentiation in symbiotic nodules in indeterminate and determinate nodulators.

根瘤菌-豆科植物共生是植物-微生物细胞内最高级的相互作用之一，主要包括共生识别、通过感染丝（ITs）感染和根瘤菌释放到根瘤中的宿主细胞。在这些过程中，基因表达模式和分子形态动力学的广泛和协调的变化，如质膜增殖和形成的细菌膜（PBM）发生。了解在这一关键阶段的转录，分子和细胞的模式是至关重要的，以阐明控制根瘤菌-宿主细胞相互作用和随后的根瘤菌-豆科植物共生固氮的分子调控网络。然而，控制根瘤菌细胞内吸收的转录和分子形态动力学景观在很大程度上仍然是未知的。此前，Ott实验室发现SYMREM 1与结瘤因子受体发生物理相互作用，并且是IT生长和根瘤菌释放所必需的，这表明SYMREM 1在M.蒺藜Li实验室已经鉴定出GmSYMREM 1是G. max，验证了GmSYMREM 1与NFR 1 α/5α之间的相互作用。Ott和Li实验室之间的合作工作还表明，根瘤菌对GmSYMREM 1的诱导受miR 172-NNC 1模块的调节。这些数据表明，苜蓿和大豆，这是不确定的和确定的结瘤，分别，可能有一个保守的机制，SYMREM 1介导的质膜纳米结构域控制根瘤菌感染和释放到宿主细胞在豆类根瘤菌共生。这项联合提案将：1）扩大并完成我们对SYMREM 1基因转录调控的联合分析; 2）使用互补方法，如ChIP-seq和启动子进化来确定我们未来的目标; 3）采用单细胞测序等方法来绘制调节细胞分化过程中的表观遗传动力学; 4）使用这些启动子不仅用于工程化允许蛋白质精确靶向PBM的合成模块，而且还解开调节这些模块的转录因子复合物;和5）使用相关显微镜通过超微结构分辨率解决形态动力学过程，并鉴定介导细菌释放的关键因子。该项目将极大地推进我们对根瘤菌胞内摄取控制机制的认识。我们将揭示和区分PBM靶向蛋白质，根瘤菌释放和宿主细胞分化的一般分子机制，在共生根瘤不确定和确定结瘤。