The Shape of Plants: exploring developmental transitions

植物的形状：探索发育转变

• 批准号: RGPIN-2019-05432
• 负责人: Wasteneys, Geoffrey
• 金额: $ 5.68万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=738272
• 关键词: Shape; Plants; exploring; developmental; transitions

Plants have evolved sensory and response mechanisms to optimize growth and development under diverse and adverse environmental conditions. Tiny regions of the plant body called meristems maintain stem cells in a quiescent state, and produce the cells that give rise to tissues and organs. Cells are displaced from the meristem, but eventually stop dividing and undergo massive growth. When and where this transition from division to differentiation occurs determines the ultimate size and shape of plant organs, and is strongly influenced by prevailing environmental conditions, and modified by stresses such as drought and salinity. The overarching goal of this research proposal is to identify and understand the mechanisms by which plants determine and coordinate the developmental transition from proliferation to differentiation. It also builds on more than three decades of research on the properties and functions of dynamic sub-cellular filaments called microtubules (MTs). MTs are essential in all eukaryotic organisms for carrying out chromosome separation, intracellular transport, directional growth and motility. The research is divided into three subprograms, each of which focusses on developmental transitions (in the context of MT function). We will first determine how two types of MT-associated proteins, MOR1 and ARK, work in concert to coordinate MT assembly and disassembly. We will determine how these proteins control MT dynamics as cells transition from one stage of development to another, but also in response to salt stress, which involves transient MT disassembly. The second objective will elucidate how the MT-associated protein CLASP and the growth hormone brassinosteroid control the transition from proliferation to differentiation. We recently discovered that CLASP sustains brassinosteroid signalling by fostering the recycling of its receptors but that brassinosteroid signalling also down-regulates CLASP. To explore this negative feedback loop further, we have engineered plants in which the CLASP gene is no longer responsive to brassinosteroids. These 'uncoupled' plants will be powerful tools for identifying the specific function CLASP plays in modulating the proliferation-differentiation transition point. Finally, we will explore how the membrane-anchored cellulose-binding protein COBRA sustains unidirectional growth during cell expansion. COBRA is highly expressed during rapid expansion and is required for the production of cellulose, which is the major tension-bearing component of plant cell walls. We recently confirmed COBRA's presence in the cell wall, but also discovered that it associates with the enzyme complexes that synthesize cellulose, which are distributed along MTs inside the cell. We will use biochemical and transcriptional assays to test our hypothesis that COBRA undergoes cleavage after interacting with cellulose, and that its subsequent association with the cellulose synthase complex modulates cellulose production.

植物具有进化的感觉和反应机制，以优化多样化和不利的环境条件下的生长和发展。称为分生组织的植物体的微小区域将干细胞保持在静止状态，并产生产生组织和器官的细胞。细胞从分生组织中移动，但最终停止分裂并经历大量生长。从分裂到分化的何时何地发生，决定了植物器官的最终大小和形状，并且受到现行环境条件的强烈影响，并通过干旱和盐度等压力进行了改变。这项研究建议的总体目标是识别和理解植物确定和协调从增殖到分化的发育过渡的机制。它还基于三十年来研究称为微管（MTS）的动态亚细胞丝的特性和功能。在所有真核生物中，MT对于进行染色体分离，细胞内转运，定向生长和运动至关重要。该研究分为三个子程序，每个子图都集中在发育过渡上（在MT函数的背景下）。我们将首先确定两种类型的MT相关蛋白MOR1和ARK如何共同协调MT组装和拆卸。我们将确定这些蛋白质如何控制MT动力学，因为细胞从一个发育的一个阶段转变为另一种阶段，也响应盐胁迫，这涉及瞬时MT拆卸。第二个目标将阐明与MT相关的蛋白质扣和生长激素腕足是如何控制从增殖到分化的过渡。我们最近发现，扣子通过促进其受体的回收来维持铜氨基固醇信号传导，但是铜氨基固醇信号传导也下调了扣子。为了进一步探索这种负反馈回路，我们已经设计了工厂，其中扣子基因不再对腕足是反应。这些“未偶联”植物将是确定在调节增殖差异过渡点时识别特定功能扣子的强大工具。最后，我们将探讨膜锚定的纤维素结合蛋白眼镜蛇在细胞膨胀过程中如何维持单向生长。眼镜蛇在快速膨胀期间高度表达，是纤维素的生产所必需的，纤维素是植物细胞壁的主要承受力成分。我们最近证实了眼镜蛇在细胞壁中的存在，但也发现它与合成纤维素合成的酶复合物相关联，该纤维素沿细胞内的MT分布。我们将使用生化和转录测定法来测试我们与纤维素相互作用后眼镜蛇经历裂解的假设，并且其随后与纤维素合酶复合物的关联可调节纤维素的产生。