Molecular Genetic Investigations of Auto-straightening Using Brachypodium Roots as Model

以短柄草根为模型的自动矫直的分子遗传学研究

• 批准号: 1951182
• 负责人: Patrick Masson
• 金额: $ 99.98万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1951182&HistoricalAwards=false
• 关键词: Molecular; Genetic; Investigations; Auto; straightening

Plants are anchored in place but can move and grow in response to the physical environment. One such remarkable response is to gravity: regardless of the position of the plant, whether turned upside down or sideways, young plant roots will grow in the direction of gravity, towards the Earth and shoots will grow away from gravity, in the direction of light. How the plant perceives and responds to gravity stimulation is a question that has intrigued scientists a century and a half, since the time of Darwin. It is now known that variations in cell growth drive the movement of roots, but the growth patterns are subtle and complicated. Recently it was discovered that during the gravity response, roots grow down by curving and also self-straightening, a mechanically puzzling but essential phenomenon related to how the roots acquire water and nutrients from the soil. This project investigates how self-straightening occurs using interdisciplinary methods, including novel imaging techniques, mathematics, molecular genetics and genomics. The long-term goal is to identify the genes that control the curving root response to gravity. Understanding how roots grow into and through the soil will open the door to manipulating and selecting for more efficient root growth. As the world faces changing water availability and deficits, this research could uncover root responses that can be harnessed for crop improvements. The project also brings the wonder of plant movement to the general public through establishing museum displays complete with images and information about root growth. Graduate and undergraduate students will be trained in inter-disciplinary biological research to help move these studies into the future.Plant organs have the ability to sense a curvature and respond by straightening, a process that is evocative of proprioception. This auto-straightening response contributes to organ's posture, an important determinant of overall plant architecture, productivity and market value. When gravistimulated, Brachypodium roots initially respond by developing a strong downward curvature whose rate decreases after the tip reaches a 45-degree angle from the vertical. At this point, the root straightens before undergoing a new round of curvature. This process reiterates several times before the tip reaches a vertical posture. From then on, the root tip continues to oscillate around the vertical. A mathematical model was built to recapitulate these complex behaviors, and used to estimate explanatory parameters of the movements for a total of 46 distinct Brachypodium accessions. This allowed the development of a genome-wide association study (GWAS) aimed at identifying contributing genes. Several DNA polymorphisms were found to be associated with the amplitude of the oscillations. The main objective of this project is to investigate the cellular characteristics of these oscillations, and study the molecular mechanisms controlling them. The specific aims are: 1) Characterize the spatio-temporal distribution of curvatures and accompanying auto-straightening phases during a graviresponse; 2) Investigate the involvement of auxin gradients in their regulation, and 3) Initiate a molecular characterization of these oscillations, using transcriptomics and GWAS approaches to identify candidate regulators. These experiments will lead to a better understanding of the molecular and cellular mechanisms that govern auto-straightening and proprioception in plants.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.

植物被固定在原地，但可以根据物理环境移动和生长。其中一个显著的反应是对重力的反应：无论植物的位置如何，无论是倒置还是侧身，年轻的植物根都会朝着重力的方向生长，朝着地球，而芽会远离重力，朝着光的方向生长。 自达尔文时代以来，植物如何感知重力刺激并作出反应，这是一个困扰科学家世纪的问题。现在人们知道，细胞生长的变化驱动着根的运动，但生长模式是微妙而复杂的。最近发现，在重力响应期间，根通过弯曲和自我拉直向下生长，这是一种机械上令人困惑但与根如何从土壤中获取水分和养分有关的基本现象。该项目研究如何使用跨学科的方法，包括新的成像技术，数学，分子遗传学和基因组学，自我矫直发生。长期目标是确定控制弯曲根对重力反应的基因。了解根系如何进入土壤并穿过土壤生长，将为操纵和选择更有效的根系生长打开大门。 随着世界面临着不断变化的水资源供应和短缺，这项研究可以揭示可用于作物改良的根系反应。该项目还通过建立博物馆展示植物运动的奇迹，并提供有关根系生长的图像和信息。研究生和本科生将接受跨学科生物学研究的培训，以帮助将这些研究推向未来。植物器官具有感知弯曲并通过拉直做出反应的能力，这是一个唤起本体感受的过程。这种自动拉直反应有助于器官的姿态，这是整个工厂结构，生产力和市场价值的重要决定因素。当重力刺激时，短柄草的根最初的反应是形成一个强烈的向下弯曲，当尖端与垂直方向成45度角后，弯曲率下降。在这一点上，牙根在经历新一轮弯曲之前变直。在尖端达到垂直姿势之前，该过程重复数次。从那时起，根尖继续围绕垂直方向振荡。建立了一个数学模型来概括这些复杂的行为，并用于估计解释参数的运动，共46个不同的短柄草加入。这使得全基因组关联研究（GWAS）的发展，旨在确定贡献基因。发现几种DNA多态性与振荡幅度相关。该项目的主要目的是研究这些振荡的细胞特征，并研究控制它们的分子机制。具体目标是：1）表征重力响应期间曲率和伴随的自动拉直阶段的时空分布; 2）调查生长素梯度在其调节中的参与，以及3）使用转录组学和GWAS方法来识别候选调节剂，启动这些振荡的分子表征。这些实验将导致更好地理解的分子和细胞机制，管理自动拉直和本体感受在plants.This奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。