EAGER: Defining the phloem-mobile proteins of Arabidopsis

EAGER：定义拟南芥韧皮部移动蛋白

• 批准号: 1643419
• 负责人: Jocelyn Malamy
• 金额: $ 28.22万
• 依托单位: University of Chicago
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1643419&HistoricalAwards=false
• 关键词: EAGER; Defining; phloem; mobile; proteins

In higher animals, blood moves throughout the body in veins and arteries, carrying nutrients, hormones and signaling molecules that coordinate the functions of different organs. Plants have an analogous fluid called phloem sap, which moves through phloem vessels to carry sugars from photosynthetic organs to the rest of the plant, and to communicate information about nutritional needs, stress or disease between distant plant organs. Scientists have only a rudimentary understanding of phloem sap-mediated signaling, primarily because it is extremely difficult to collect a phloem sap sample that is not heavily contaminated by fluids from the surrounding cells. While evidence suggests that hundreds of proteins exist in the phloem sap, only a small number are confirmed to actually move and only one has a known function. In this project, the researchers will identify hundreds of phloem sap proteins with confirmed long distance movement. The researcher's novel approach involves grafting two plants with distinct genetic sequences together and then using protein sequence analysis to identify proteins from plant 1 in the phloem vessels of plant 2. If successful, this project will generate the first large dataset of mobile phloem sap proteins, overcoming the current bottleneck in the field of intra-plant signaling. The identity of these proteins will catalyze new research directions and will impact a large number of plant biologists. Phloem signaling is an essential component of the plant's ability to survive biotic and abiotic stresses. Therefore, this project will suggest new strategies for improving crop plant growth and yield.Despite the exciting potential of intra-plant communication via phloem-mobile proteins, there is no current consensus as to the identity of the phloem sap proteome in most plants, including the model plant Arabidopsis thaliana where researchers could best test the function of these proteins. The PI will use a grafting approach to definitively identify proteins that move long distance through a graft union. Taking advantage of the extensive sequence data available for over 1000 Arabidopsis accessions, the PI will identify grafting partners where sequence variation leads to amino acid differences in ~1100 predicted phloem sap proteins. Heterografts will be made, protein samples enriched for phloem sap will be collected from the scion, and Mass Spectrometry will be used to identify rootstock proteins that have travelled to the scion tissue. The proteome generated by this project will rely on observed protein movement. This is in contrast to previous attempts in the field to define the phloem sap proteome based on direct phloem sap extraction, a process that is extremely difficult and plagued with technical difficulties. The definition of hundreds of mobile proteins will overcome the current bottleneck in this field, where the existing phloem sap proteomes are contradictory and generally acknowledged to have large sampling artefacts. Once in hand, the phloem sap proteome will lead to testable hypotheses about phloem sap signaling based on the identity and function of the mobile proteins.

在较高的动物中，血液以静脉和动脉的形式在整个体内移动，携带营养，激素和信号分子，以协调不同器官的功能。 植物具有称为韧皮部SAP的类似液体，该液体通过韧皮部血管移动，将糖从光合器官带到植物的其余部分，并在远处植物器官之间传达有关营养需求，压力或疾病的信息。 科学家只对韧皮部SAP介导的信号传导有基本的理解，这主要是因为很难收集没有周围细胞的流体污染的韧皮部SAP样品。 虽然证据表明，韧皮部SAP中存在数百种蛋白质，但只有少数数字可以实际移动，只有一个具有已知功能。 在这个项目中，研究人员将确定数百种具有确认的长距离运动的韧皮部SAP蛋白。 研究人员的新方法涉及将两种具有不同遗传序列的植物植入植物2中的植物1中的蛋白质1中的蛋白质1。 这些蛋白质的身份将催化新的研究方向，并影响大量植物生物学家。 韧皮部信号传导是植物生物和非生物胁迫生存能力的重要组成部分。 因此，该项目将提出改善农作物植物生长和产量的新策略。尽管在植物内通过Phloem-Mobile蛋白质进行交流的令人兴奋的潜力，但目前尚无共识，即大多数植物中Phloem SAP蛋白质组的身份，包括大多数植物，包括模型植物Arabidopsis Thaliana，研究人员可以在其中最能测试这些蛋白质的功能。 PI将使用嫁接方法确定识别通过移植结合的长距离移动的蛋白质。 利用可用于1000多个拟南芥加入的广泛序列数据，PI将识别嫁接伙伴，其中序列变化导致〜1100个预测的韧皮部SAP蛋白的氨基酸差异。 将制作异临床，将从Scion中收集富含韧皮部SAP的蛋白质样品，并将使用质谱法来鉴定已进入Scion组织的砧木蛋白。 该项目产生的蛋白质组将依赖于观察到的蛋白质运动。 这与以前在现场尝试根据直接韧皮部SAP提取来定义韧皮部SAP蛋白质组的尝试相反，这一过程极为困难并且受到技术困难的困扰。 数百种移动蛋白的定义将克服该领域的当前瓶颈，在该领域，现有的韧皮部SAP蛋白质组是矛盾的，并且通常被公认为具有大型采样人工制品。 一旦掌握，韧皮部SAP蛋白质组将根据移动蛋白的身份和功能导致有关韧皮部SAP信号传导的可检验假设。