The role of SMXL7 in plant vessel formation

SMXL7 在植物导管形成中的作用

• 批准号: 541639494
• 负责人: Professor Dr. Thomas Greb
• 金额: --
• 依托单位: Centre for Organismal Studies (COS)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/541639494?language=en
• 关键词: role; SMXL7; plant; vessel; formation

Continuous growth and tissue formation are characteristic for plant development and important for aligning distinct body structures with changing environmental conditions. Cambium-driven radial growth of shoots and roots of dicotyledonous species is an important feature of this growth mode, and key for biomass production and for the long-term sequestration of CO2. Cambium stem cells (CSCs) proliferate usually providing wood (i.e. xylem) cells inwards and bast (i.e. phloem) cells outwards. Within xylem and phloem tissues, various cell types fulfil highly specialized functions like water transport by xylem vessel elements or sugar transport by phloem sieve elements. However, mechanisms regulating CSC-associated cell fate decisions to cope with stressful environmental conditions are largely unknown. Here, we propose to tackle this gap of knowledge in the context of a PhD project by identifying gene targets of the strigolactone (SL) signaling pathway regulating vessel element formation. We recently uncovered the impact of the SL signaling pathway on the formation of vessel elements in Arabidopsis thaliana. The central observations are that plants in which the SL pathway is impaired, density and size of vessel elements within radially growing organs are increased, whereas SL application has the contrary effect. Based on these observations, we propose a role of the SL-signaling pathway in mediating structural plasticity and water transport capacities in plants in response to fluctuating water availabilities. SUPPRESSOR OF MAX2 1-LIKE 6 (SMXL6), SMXL7 and SMXL8 proteins are transcriptional regulators which are ubiquitinated and subsequently degraded upon the initiation of SL signaling. However, how SL signaling is integrated into developmental programs leading to the formation of vessel elements, i.e. which genes are targeted by SMXL proteins in an SL-dependent manner in developing xylem cells is unclear. This knowledge, however, is key to estimate the significance of environmental integration into plant vascular development and to characterize environment-plant interaction under current and future climatic conditions in a broader spectrum of species. Here, we will generate this knowledge by taking advantage of genetic tools available in Arabidopsis thaliana. Our aim will be achieved by i) elucidation of the SMXL7 chromatin binding profile in a genome-wide fashion, ii) identification of SMXL7-dependent genes in a cambium context and, iii) verification of the relevance of identified targets in the context of vessel formation using genetic and biochemical means.

连续生长和组织形成是植物发育的特征，对于使不同的身体结构与变化的环境条件相一致非常重要。形成层驱动的双子叶植物茎和根的径向生长是这种生长模式的一个重要特征，也是生物量生产和长期封存CO2的关键。形成层干细胞（CSC）增殖通常向内提供木质（即木质部）细胞，向外提供韧皮（即韧皮部）细胞。在木质部和韧皮部组织中，各种细胞类型履行高度专门化的功能，如木质部导管元件的水运输或韧皮部筛元件的糖运输。然而，调节CSC相关细胞命运决定以科普应激环境条件的机制在很大程度上是未知的。在这里，我们建议解决这一知识差距的背景下，一个博士项目，通过确定基因靶的独脚金内酯（SL）信号通路调节血管元素的形成。我们最近发现的SL信号通路的导管元件在拟南芥的形成的影响。中心的意见是，SL途径受损的植物，密度和大小的导管元件内径向生长的器官增加，而SL应用程序具有相反的效果。基于这些观察结果，我们提出了SL信号通路在介导植物的结构可塑性和水运输能力，响应波动的水分供应的作用。MAX 2 1-LIKE 6（SMXL 6）、SMXL 7和SMXL 8蛋白的供应者是转录调节因子，其在SL信号传导起始时被泛素化并随后降解。然而，SL信号传导如何整合到导致导管元件形成的发育程序中，即在发育木质部细胞中哪些基因以SL依赖性方式被SMXL蛋白靶向尚不清楚。然而，这方面的知识，是关键，以估计环境整合到植物维管发育的意义，并在更广泛的物种在当前和未来的气候条件下，表征环境-植物相互作用。在这里，我们将通过利用拟南芥中可用的遗传工具来产生这些知识。我们的目标将通过以下方式实现：i）以全基因组方式阐明SMXL 7染色质结合谱，ii）在形成层背景中鉴定SMXL 7依赖性基因，以及iii）使用遗传和生物化学手段验证所鉴定的靶标在血管形成背景中的相关性。