Transitions: Creating a Trans-Disciplinary Approach to Discover Multi-Scale Control Mechanisms of Plant Morphogenesis

该奖项的全部或部分资金来自《2021年美国救援计划法案》(公法117-2)。在作物物种中，植物的结构是产量的主要决定因素，并可以定义其作为可再生生物材料的价值。细胞是建筑特征的基石，它们的生长是由巨大的内部压力驱动的，这种压力使细胞膨胀，并使坚韧的外部细胞承受非常高的张力。细胞壁的材料特性决定了在广泛的空间尺度上的生长模式。植物生物学中的一个主要挑战是了解细胞内的遗传途径和蛋白质如何控制胞外多糖的属性来决定生长模式。细胞内的蛋白质机器需要解释来自细胞壁的信息，以便细胞大小和形状的变化是可以预测的。植物生长系统可以被认为是遗传编码的生物力学机器，以可预测的方式自我组装。由于缺乏将物理学和材料科学的概念与植物遗传学和细胞生物学的概念相结合的跨学科方法，在揭示潜在控制机制方面的进展受到了阻碍。生物学家迫切需要能够开发和充分描述植物发育的机械模型，为理解植物形态发生的细胞机制和这些知识在农业中的下游应用提供知识基础。这个项目中的研究和学习活动将为分析和操纵增长模式提供新的方法。工程学和生物学方面的资深专家和初级科学家将广泛地将机械建模和微观机械分析与植物细胞生物学相结合。研究团队将创建学习计划，使这种交叉培训具有普遍性，并使更多用户友好的模式能够被研究和教育界广泛采用。美国救援计划的资金为这位研究人员在其职业生涯的关键阶段提供了支持。植物形态控制是一个多尺度的综合过程，在这个过程中，细胞骨架和细胞壁系统相互作用，产生适应性的生长模式。然而，我们对亚细胞生长模式是如何决定的，以及它们是如何扩展到影响细胞、组织和器官水平的表型的理解是未知的。历史上关于均匀弥漫生长的假设可能是不正确的，因为大多数细胞类型都有不同的生长模式。此外，很难定量预测墙体中的拉力模式，因为它们取决于充气压力、多种类型的几何特征和墙体的材料特性。有限元模型提供了一条有效的前进路径，因为它将细胞模拟为薄壁加压壳，并可用于定量模拟具有真实细胞和组织几何形状的拉力和生长模式。该模型还对驱动植物细胞生长的细胞壁异质性的位置和类型以及细胞骨架如何感知细胞壁力做出了具体预测。这一“向卓越过渡”项目将开发一种新颖的学习和研究计划，使生物学家和工程师能够严格整合有限元建模、实验验证和模型改进。这种方法和将要分析的单细胞和器官系统，有可能定义从纳米到厘米尺度的可概括的形态发生“规则”，以编程功能特征。这项研究将作为一个框架，创建更复杂的模型，提供足够的细节，为基因工程植物表型的策略提供信息。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).In crop species, the architecture of the plant is a primary determinant of yield and can define its value as a renewable biomaterial. Cells are the building blocks of architectural traits and their growth is driven by a large internal pressure that makes the cells turgid and subjects the tough outer cell to very high tensile forces. The material properties of the cell wall determine the patterns of growth across a wide range of spatial scales. A major challenge in plant biology is to understand how genetic pathways and proteins inside the cell control the extracellular properties of polysaccharides to dictate growth patterns. The protein machineries inside the cell need to interpret information from the cell wall so that changes in cell size and shape can be predictable. Plant growth systems can be thought of as genetically encoded biomechanical machines that self-assemble in predictable ways. Progress in unravelling the underlying control mechanisms has been hindered by the lack of interdisciplinary approaches that combine the concepts of physics and material science with those of plant genetics and cell biology. There is a strong need for biologists to be able to develop and fully characterize mechanical models of plant development that provide the knowledge base for understanding the cellular mechanisms of plant morphogenesis and the downstream application of this knowledge to agriculture. The research and learning activities in this project will seed new approaches to analyze and manipulate growth patterns. Established experts and junior scientists in engineering and biology will broadly integrate mechanical modelling and micromechanical analyses with plant cell biology. The research team will create learning programs to make this cross-training generalizable and to make more user friendly models that can be widely adopted by the research and educational communities. American Rescue Plan funding provides support for this investigator at a critical stage in his career.Plant morphology control is a multi-scale integrated process in which cytoskeletal and cell wall systems interact to generate adaptive growth patterns. However, our understanding of how subcellular growth patterns are determined and how they scale to influence cell-, tissue-, and organ-level phenotypes are not known. Historical assumptions about uniform diffuse growth are likely incorrect as most cell types have heterogeneous growth patterns. In addition, it has been difficult to quantitatively predict tensile force patterns in the wall, because they depend on turgor pressure, multiple types of geometric features, and the material properties of the wall. Finite element modelling provides an efficient path forward because it simulates the cells as a thin-walled pressurized shells and can be used to quantitatively simulate the tensile forces and growth patterns with realistic cell and tissue geometries. The model also makes specific predictions about the location and type of cell wall heterogeneity that drive plant cell growth and how cell wall forces can be sensed by the cytoskeleton. This “Transitions to Excellence” project will develop a novel learning and research program that will broadly enable biologists and engineers to rigorously integrate finite element modelling, experimental validation, and model refinement. This approach and the single cell and organ systems that will be analyzed, have the potential to define generalizable morphogenesis “rules” that operate from the nanometer to centimeter scales to program functional traits. This research will serve as a framework to create more sophisticated models with sufficient detail to inform strategies to genetically engineer plant phenotypes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.