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

重新评估植物 I 型 H-PPase 的生物学功能

• 批准号: 1557890
• 负责人: Roberto Gaxiola
• 金额: $ 67.5万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-03-01 至 2020-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1557890&HistoricalAwards=false
• 关键词: Reassessing; Biological; Functions; Plant; Type

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.

植物利用水和阳光的能量来制造能量密集的糖。在叶子中产生糖后，糖需要转移到植物的其他部分，在那里消耗能量。这些消耗组织被称为“汇”。与我们的循环系统类似，植物有一个称为韧皮部的细胞网络，它允许糖从来源（叶子）移动到库组织。 长期以来，科学家们一直寻求通过调节糖的运动来提高农作物的产量，其理论是，如果增加供应，就可以提高产量，同时减少昂贵且有环境问题的化肥的投入。之前的工作已经确定了韧皮部内的转运蛋白，本提案旨在表征这一关键调节剂在糖转运中的功能。 明确这种转运蛋白如何将糖转移到植物内的各个组织，将使科学家能够制定优化作物糖转运的策略，从而提高产量，同时减少农业生产对环境的影响。该项目首席科学家的西班牙裔血统使该团队在吸引西班牙裔受众方面具有优势，通过用西班牙语交流复杂的科学主题来激发公众和学生对科学的兴趣。参与该项目的科学家将组织一次关于农业生物技术和社会的国际会议，还将开发双语网络教学工具以提高科学素养。光同化物在其生产和利用地点之间的划分是植物生长和发育的关键决定因素。新出现的证据表明，光同化物分配的调节部分是由 I 型 H+-PPase 介导的。这种转运蛋白在液泡膜中的作用已被确定。然而，最近的研究显示这种转运蛋白在质膜（PM）定位，并确定它在韧皮部伴随细胞（CC）中显着表达，但这种独特的功能尚未得到解决。研究人员提出，这种酶具有两种相反的作用，PPi 水解和合成，有助于一系列促进植物生长的事件。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，一系列遗传、免疫组织化学和生理学实验将确定该泵如何影响同化物的分配。这项基础研究将 H+-PPase 分类为参与光合产物分配和代谢的中心介质。