Reassessing the Biological Functions of the Plant Type I H+-PPase

植物利用水和来自阳光的能量来制造能量密集的糖。在叶子中产生糖之后，糖需要被转移到植物的其他部分，在那里消耗这种能量。这些消耗组织被称为“水槽”。类似于我们的循环系统，植物有一个称为韧皮部的细胞网络，允许糖从源（叶子）移动到库组织。 长期以来，科学家们一直试图通过调节糖的运动来增加作物产量，其理论是，如果供应增加，产量可以增加，同时减少昂贵和环境问题的肥料投入。以前的工作已经确定了运输韧皮部和本建议的目的是描述这个关键调节糖运输的功能。 研究这种转运蛋白如何将糖转移到植物内的各种组织，将使科学家能够制定策略，优化作物中的糖转移，提高产量，同时减少生产农业对环境的影响。该项目的首席科学家的西班牙裔根源使该团队通过用西班牙语交流复杂的科学主题来吸引西班牙裔观众，从而激发公众和学生对科学的兴趣。参与这一项目的科学家将组织一次关于农业生物技术与社会的国际会议，并将开发双语网络教学工具，以促进科学知识，光合作用在其生产和利用地点之间的分配是植物生长和发育的一个关键决定因素。新出现的证据表明，光合分配的调节部分介导的I型H+-PPase。这种转运蛋白的作用已经建立在液泡膜，然而，这种独特的功能一直不稳定，最近的工作表明质膜（PM）定位这种转运蛋白，并建立它是显着表达在韧皮部的伴侣细胞（CC）。研究人员提出，这种酶有两个相反的作用，PPi水解和合成，有助于激发植物生长的级联事件。他们将测试拟南芥H+-PPase在异源系统（酿酒酵母）和植物中合成PPi的能力。同时，一系列的遗传，免疫组织化学和生理实验将确定如何泵影响同化物的分配。本基础研究将对参与光合产物分配和代谢的H+-PPases进行分类。

Plants use water and the energy from sunlight to make energy-dense sugars. After production in the leaves, the sugar needs to be moved to other parts of the plant where this energy is consumed. These consuming tissues are termed 'sinks'. Analogous to our circulatory systems, plants have a network of cells called the phloem that allow the movement of sugars from source (leaves) to the sink tissues. Scientists have long sought to increase the yield of crops by regulating the movement of sugars, the theory being that if supplies are increased, yield can be increased while the input of costly and environmentally problematic fertilizers is diminished. Previous work has identified a transporter within the phloem and this proposal aims to characterize the function of this key regulator in sugar transport. Specifying how this transporter moves sugar to various tissues within the plant will allow scientists to develop strategies to optimize sugar translocation in crops that increase yield while reducing the environmental impacts of production agriculture. The Hispanic roots of the lead scientist for this project give this team an edge in engaging Hispanic audiences by communicating complex scientific topics in Spanish to ignite interest in science among the general public and among students. The scientists involved in this project will organize an international meeting on agricultural biotechnology and society, and will also develop bilingual web-based teaching tools to promote scientific literacy.The partitioning of photoassimilates between their sites of production and utilization is a key determinant of plant growth and development. Emerging evidence suggests regulation of photoassimilate partitioning is mediated in part by a type I H+-PPase. A role for this transporter has been established at the tonoplast; however, this exclusive function has been unsettled by recent work showing plasma membrane (PM) localization of this transporter and establishing that it is prominently expressed in phloem companion cells (CC). The researchers propose this enzyme has two opposing roles, PPi hydrolysis and synthesis that contribute to a cascade of events that energize plant growth. They will test the capacity of the Arabidopsis thaliana H+-PPase to synthetize PPi in a heterologous system (Saccharomyces cerevisiae) and in plants. Concurrently, a series of genetic, immunohistochemical and physiological experiments will determine how this pump affects the partitioning of assimilates. This fundamental research will catalog that H+-PPases as a central mediator involved in the allocation and metabolism of photosynthates.