Exodermis Differentiation and Function

外皮分化和功能

• 批准号: 2118017
• 负责人: Siobhan Brady
• 金额: $ 132.34万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2118017&HistoricalAwards=false
• 关键词: Exodermis; Differentiation; Function

The climate across the United States is increasingly unpredictable, with rising temperatures and longer stretches of extreme changes in water availability such as drought and flooding. These events change arable land availability and reduce crop yield. Cells in the plant root are responsible for transporting water and mineral nutrients to the rest of the plant and their cells are the first responders to changes in water availability. One of these cell types is the exodermis, which is known to produce a barrier in its cell wall that is proposed to aid plants in becoming drought tolerant. However, little is known regarding the genes that control its development or response to the environment. In this project, classical developmental biology approaches coupled with single cell genomics and CRISPR-Cas9 gene editing will be used to map the pathways that produce the root exodermis and its barrier, and to determine how this barrier helps tomato plants tolerate drought. The results of this research can be directly used to generate plants better able to respond to changes in water availability and facilitate more sustainable agriculture. The research will be fully integrated into education efforts for undergraduate and graduate students at the University of California, Davis and will provide them with cutting-edge training and expertise. These students will further establish a compendium of root cell barriers that plants produce to counter a harsh environment. These will enable scientists to harness natural solutions for future plant breeding.Botanical studies report that up to 93% of plant species have an exodermis cell type that underlies the root epidermis and which produces a barrier. In tomato, the exodermis first forms a polarized lignin cap that restricts passive diffusion between cells. The genes that regulate formation of the exodermis lignin barrier are distinct from those that regulate endodermis development and production of the Casparian Strip barrier. The goals of this project are to map the genetic pathway that produces the exodermis and its barrier, to show how the barrier regulates the transport of specific mineral ions and to determine how the barrier functions to help a plant tolerate drought stress. Existing exodermis differentiation genes will be ordered in a genetic pathway using developmental genetics. CRISPR-Cas9 gene editing will be used in a targeted approach to generate pair-wise mutations of exodermis-enriched transcription factors and signaling genes to determine which of these promote formation of the lignin barrier. This approach will be directly integrated as a Course-Based Undergraduate Research opportunity at UC Davis and will form the basis of long-term undergraduate research projects. Single cell transcriptome sequencing will be used to identify genes that control exodermis specification via asymmetric cell divisions of its stem cell precursors. Finally, the exodermis and endodermis lignin barriers will be genetically uncoupled in order to determine how each of these directly contribute to plant drought responses and mineral ion transport using inductively coupled plasma mass spectrometry.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.

美国各地的气候越来越不可预测，气温不断上升，干旱和洪水等水资源供应出现了更长时间的极端变化。这些事件改变了耕地的可获得性，降低了作物产量。植物根部的细胞负责将水和矿物质养分输送到植物的其余部分，它们的细胞是对水分供应变化的第一反应。其中一种细胞类型是外皮，已知它会在细胞壁中产生一种屏障，这被认为是为了帮助植物变得耐旱。然而，人们对控制其发育或对环境反应的基因知之甚少。在这个项目中，经典的发育生物学方法与单细胞基因组学和CRISPR-Cas9基因编辑相结合，将被用来定位产生根外皮层及其屏障的途径，并确定这种屏障如何帮助番茄植株耐旱。这项研究的结果可以直接用于培育能够更好地应对水资源供应变化的植物，并促进更可持续的农业。这项研究将完全融入加州大学戴维斯分校本科生和研究生的教育工作，并将为他们提供尖端培训和专业知识。这些学生将进一步建立植物产生的根细胞屏障的纲要，以对抗恶劣的环境。植物学研究报告称，高达93%的植物物种都有一种外胚层细胞类型，它位于根表皮之下，并产生一种屏障。在番茄中，外皮首先形成一个极化的木质素帽，限制细胞之间的被动扩散。调控外胚层木质素屏障形成的基因与调控内胚层发育和产生凯氏带屏障的基因是不同的。该项目的目标是绘制产生外胚层及其屏障的遗传路径图，展示屏障如何调节特定矿物质离子的运输，并确定屏障如何发挥作用，帮助植物耐受干旱胁迫。现有的外皮分化基因将利用发育遗传学在遗传途径中进行排序。CRISPR-Cas9基因编辑将被用于一种有针对性的方法，以产生外皮丰富的转录因子和信号基因的成对突变，以确定其中哪些促进木质素屏障的形成。这种方法将被直接整合为加州大学戴维斯分校基于课程的本科生研究机会，并将形成长期本科生研究项目的基础。单细胞转录组测序将用于识别通过干细胞前体的不对称细胞分裂来控制外皮规格的基因。最后，外胚层和内胚层木质素屏障将在基因上分离，以便使用电感耦合等离子质谱仪确定它们如何直接影响植物干旱反应和矿物质离子运输。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。