Regulation of nutrient homeostasis by the CBL-CIPK calcium sensor-kinase network in Arabidopsis

植物生长需要平衡的矿物质营养供应，但今天的土壤往往缺乏必需的矿物质，如氮，磷（P）和钾（K+）。作物生产严重依赖于肥料的使用，但过度使用肥料是昂贵的，危害环境健康，并且它是不可持续的，因为一些必需的矿物质（例如，钾和磷矿石）是有限的自然资源。作为一种替代策略，培育具有新性状的植物，使它们能够在营养不平衡的土壤中生长，已成为全球关注的可持续农业长期解决方案。为了实现这一目标，我们需要了解使植物能够响应和适应土壤中不断变化的矿物质营养状态的分子网络。换句话说，我们需要知道当土壤中含有过多或过少的特定矿物质时，植物是如何维持矿物质营养的动态平衡的。该项目将探讨植物适应土壤养分供应的遗传和分子机制，从而建立培育几乎不需要肥料的作物的知识库，从而支持可持续农业。这项研究将通过主要研究者在加州大学伯克利分校教授的主要课程以及通过他实验室的独立研究项目对本科生和研究生教育产生额外的影响。NSF项目还将加强以当地高中为重点的努力，鼓励在科学领域代表性不足的学生接受高等教育，并将生物学研究作为一种职业选择。为高中生举办的暑期讲习班已经持续了十年，并将在该项目下继续举办。研究生领导的努力“CAL学生为少数民族的成功”外展主要是西班牙裔学生在当地高中的一般科学教育。URM学生通过生物技术合作伙伴的夏季研究培训也将继续。这些活动的结合将有助于促进这些学生的教育成功。植物不断监测土壤中的养分状况，并通过控制离子穿过质膜（用于吸收）和液泡膜（用于储存和再动员）的运输来维持养分动态平衡。然而，土壤中的营养状态和植物膜运输的信号机制在很大程度上是未知的。首席研究员的实验室发现了CBL-CIPK钙信号网络，该网络在许多细胞途径中发挥作用，包括营养传感。他们的NSF支持的研究将CBL-CIPK信号传导机制与质膜和液泡膜（液泡膜）的运输活动调节联系起来，这是植物细胞中营养稳态的两个最重要的位点。实验证据也出现了新的信号串扰，在营养传感的早期阶段，CBL-CIPK模块和其他信号激酶和磷酸酶之间。拟议的研究将追求这些令人兴奋的新线索与以下具体目标：1。确定CBL-CIPK调节液泡膜钾转运蛋白活性的分子机制。2.鉴定CBL-CIPK信号传导模块靶向的液泡镁螯合转运蛋白。3.了解激活CBL-CIPK模块的低钾反应的早期事件。4.研究质膜CBL-CIPK模块与液泡膜CBL-CIPK模块之间的功能关系。该研究将受益于PI小组在模型植物系统中的独特专业知识，这些系统适合于膜片钳和细胞生物学分析，并结合遗传和生物化学方法。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

Plant growth requires a balanced supply of mineral nutrients but today’s soil is often deficient in essential minerals such as nitrogen, phosphorus (P), and potassium (K+). Crop production heavily relies on use of fertilizers but excessive fertilizer use is costly, endangers environmental health, and it is not sustainable because some essential minerals (e.g., potash and phosphorus rock) are limited natural resources. As an alternative strategy, breeding plants with new traits enabling them to grow in nutrient-imbalanced soil, has become a global focus for long-term solution to sustainable agriculture. To achieve this goal, we need to understand the molecular networks that allow plants to respond and adapt to the constantly changing status of mineral nutrients in the soil. In other words, we need to know how plants maintain the homeostasis of mineral nutrients when soil contains too much or too little of specific minerals. This project will address the genetic and molecular mechanisms underlying plant adaptation to soil nutrient availability, thereby establishing the knowledgebase for breeding crops with little need of fertilizers, thus supporting sustainable agriculture. The research will have an additional impact on undergraduate and graduate education through major courses the principal investigator teaches at the University of California, Berkeley and through independent research programs in his laboratory. The NSF project will also enhance the efforts that focus on local high schools to encourage students underrepresented in science to pursue higher education and explore biology research as a career option. A summer workshop for high school students has been ongoing for ten years and will continue under this project. Graduate students-led effort “CAL Students for Minority Success” outreaches mainly Hispanic students in the local high schools on general science education. Summer research training of URM students through Biotech Partners will also continue. This combination of activities will help promote success in education for these students. Plants constantly monitor nutrient status in the soil and maintain nutrient homeostasis by controlling ion transport across the plasma membrane (for uptake) and tonoplast (for storage and remobilization). However, the signaling mechanism linking nutrient status in the soil and membrane transport in plants is largely unknown. The principal investigator’s laboratory discovered the CBL-CIPK calcium signaling network that functions in a number of cellular pathways including nutrient sensing. Their NSF-supported studies connected the CBL-CIPK signaling mechanism to the regulation of transport activities at the plasma membrane and vacuolar membrane (tonoplast), the two most important sites for nutrient homeostasis in plant cells. Experimental evidence also emerged for new signaling crosstalk, at the early stage of nutrient sensing, between the CBL-CIPK modules and other signaling kinases and phosphatases. The proposed research will pursue these exciting new leads with the following specific objectives: 1. To identify the molecular mechanism by which CBL-CIPK regulates the activity of K-transporters in the vacuolar membrane. 2. To identify the transporters targeted by CBL-CIPK signaling modules for vacuolar Mg sequestration. 3. To understand the early events of low-K response that activates CBL-CIPK modules. 4. To examine the functional relationship between the CBL-CIPK modules at the plasma membrane and those at the tonoplast. The research will benefit from the unique expertise of the PI group in the model plant systems that are amenable to patch-clamp and cell biology analysis in combination with genetic and biochemical approaches.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.