Diving Deeper: Unravelling How Plants Regulate Root Growth Angle

深入研究：揭示植物如何调节根部生长角度

• 批准号: BB/X014843/1
• 负责人: Rahul Bhosale
• 金额: $ 87.92万
• 依托单位: University of Nottingham
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FX014843%2F1
• 关键词: Diving; Deeper; Unravelling; How; Plants

Limited water and nutrient availability are the major constraints for global crop production and food security. These constraints are intensifying over time given the impact of climate change on water availability and the drive to reduce fertiliser inputs to make agriculture more environmentally sustainable. Therefore, developing crops with improved nutrient and water capture efficiency could provide the solution to make significant improvements in stress resilience and yields in our crops to meet the food demand of an increasing world population. In this context, root angle is a promising root architectural trait as it critically influences nutrient and water capture from different soil profiles. For instance, steeper root angle accesses mobile water and nitrogen from deeper soils, while shallow root angle improves capture of immobile phosphorous from topsoil. Crop root systems include different root types (such as primary, seminal, lateral and crown), which grow at different angles to efficiently capture resources from different soil profiles. These different root angles are determined by gravitropic and anti-gravitropic offset (AGO) mechanisms. Previous research has uncovered many genes involved in gravitropic response machinery, however such knowledge about AGO mechanism is limited. To bridge this gap, we recently identified a novel gene (called Enhanced Gravitropism 1 i.e., EGT1) involved in AGO mechanism. A mutation within this gene causes all root types to grow only vertically downwards as it hinders their ability to maintain different growth angles. Our research further identified that mutant roots are defective in mainly two biological processes called as reactive oxygen species (ROS) maintenance and cell wall stiffness. As ROS levels in the root are known to determine cell wall's stiffness or looseness, we proposed a new AGO mechanism that EGT1 gene regulates ROS dependant cell wall stiffness to control root angle in different root types (Fusi et al., 2022. PNAS). In this BBSRC New Investigator grant we will investigate the proposed AGO mechanism in barley roots to determine how it allows different root types to grow and capture water and nutrients efficiently from different soil profiles. We will first determine where in the root (specific tissues and growth zones) EGT1 gene is transcribed and the protein is made and accumulates. We will then express EGT1 specifically in these tissues and zones in the egt1 mutant (called complementation) to confirm tissue and zone predominantly required for EGT1 function. Next, we will determine how EGT1 controls downstream targets involved in ROS and cell wall stiffness processes. Finally, we will grow the wildtype, mutant and tissue and zone-specific complementation lines under water, nutrient and high temperature stress conditions to understand how this AGO mechanism is used by plant to change root angle in response to these conditions. We will also uncover whether change in angle in the mutant vs wildtype and complementation line roots are better able to grow under these abiotic stress conditions.The knowledge gained in this study will provide vital new information about EGT1 and its key downstream targets involved in AGO mechanism and controlling root angle in response to environmental cues. This will help breeders to design novel approaches to enhance resource capture and improve yield in crops, supporting efforts to improve food security in the UK and worldwide. The remit of our project thus falls under a strategic priority area supported by the BBSRC Bioscience for Sustainable Agriculture and Food.

有限的水和养分利用率是全球作物生产和粮食安全的主要限制。鉴于气候变化对水的供应产生影响以及减少肥料投入以使农业在环境上更可持续性的动力，这些限制会随着时间的推移加剧。因此，开发具有改善营养和捕获水效率的农作物可以提供解决方案，以显着改善我们的农作物的压力弹性和产量，以满足越来越多的世界人口的食物需求。在这种情况下，根角是一个有希望的根建筑特征，因为它严重影响了来自不同土壤剖面的养分和水捕获。例如，较陡的根角可以从更深的土壤中获取移动水和氮，而浅根角度则改善了从表土中捕获固定的磷。农作物根系包括不同的根类型（例如初级，精确，侧面和牙冠），它们以不同的角度生长以有效地从不同的土壤剖面中捕获资源。这些不同的根角是由重力和抗极力偏移（AGO）机制确定的。先前的研究发现了许多参与重力反应机制的基因，但是关于AGO机制的这种知识受到限制。为了弥合这一差距，我们最近确定了一个新的基因（称为增强的雷神1，即EGT1），参与了AGO机制。该基因内的突变导致所有根类型仅在阻碍其维持不同生长角度的能力时垂直向下生长。我们的研究进一步确定，突变根在两个生物学过程中是有缺陷的，称为活性氧（ROS）维持和细胞壁刚度。由于已知根中的ROS水平可以确定细胞壁的刚度或松散性，因此我们提出了一种新的AGO机制，该机制EGT1基因调节ROS依赖性细胞壁刚度以控制不同根类型的根角（Fusi等，2022。PNA）。在此BBSRC新研究者拨款中，我们将研究大麦根中提出的AGO机制，以确定其如何允许不同的根类型从不同土壤剖面有效地生长和捕获水和营养。我们将首先确定在根中（特定的组织和生长区域）EGT1基因被转录，并制成蛋白质并积聚。然后，我们将在EGT1突变体（称为互补）的这些组织和区域中特别表达EGT1，以确认EGT1功能的组织和区域。接下来，我们将确定EGT1如何控制与ROS和细胞壁刚度过程有关的下游目标。最后，我们将在水，养分和高温应力条件下种植野生型，突变体和组织以及区域特异性互补线，以了解植物如何使用这种AGO机制来改变对这些条件的根角度。我们还将发现突变体与野生型和互补线根中的角度的变化是否能够在这些非生物应力条件下更好地生长。本研究中获得的知识将为EGT1提供有关EGT1及其在AGO机制中涉及的关键下游目标的重要新信息，并控制了对环境线索的根角度。这将帮助育种者设计新颖的方法，以增强资源的捕获并提高农作物的产量，从而支持改善英国和全球粮食安全的努力。因此，我们项目的职责属于BBSRC生物科学​​支持可持续农业和食品的战略优先领域。