Characterization of GC ABA Receptor Coupled to KAT1 Expressed in Xenopus Oocytes

城市化、洪水、干旱和土壤盐碱化正在减少为不断扩大的世界人口提供粮食所需的土地面积。随着全球为未来粮食生产保护农田的持续努力，了解植物如何发挥作用，以便它们能够被培育或改良，以在更恶劣的环境中生存，这一点很重要。植物功能的一个关键方面是跨膜的离子、水分和营养物质的移动。本研究的重点是受体、离子通道、转运体及其调控机制(S)。非洲爪哇卵母细胞系统用于植物基因的功能性表达。MRNA的来源是保卫细胞，因为它们在控制水分损失和气体交换方面起着关键作用。由于对蚕豆保卫细胞的离子通道和信号转导的研究非常广泛，因此选择蚕豆作为实验植物。采用双电极电压钳(TEVC)技术。初步结果表明，注入蚕豆保卫细胞基因的卵母细胞表达一种GC特异性的ABA受体，该受体抑制内向整流性K+通道KAT1的活性。本研究将验证这样的假设：ABA对KAT1的调控是通过细胞外面向质膜的受体实现的。该受体的cDNA克隆将被分离出来。GC特异性ABA受体的鉴定将导致ABA受体的一个亚型的鉴定。通过保持受体之间的同源性来分离其他亚型是可能的。来自分离克隆的测序信息将允许使用生物信息学来识别数据库中具有相关功能的其他蛋白质。这项研究的长期目标是了解ABA在光合作用中如何控制水和二氧化碳交换过程中的离子吸收。概述的研究将允许学生在分子生物学、电生理学和生物信息学方面进行培训。已识别的植物基因将为植物功能的基因改造和除草剂或化学操作提供靶标，从而使植物能够在不适宜生存的环境条件下生存。

Urbanization, flooding, drought and salinization of soil are diminishing landmass needed to supply food for an expanding world population. Together with contined global efforts to safeguard agricultural land for future food production, it is important to understand how plants function so that they can be bred or modified to survive the harsher environments. A critical aspect of plant function is ion, water and nutrient movement across membranes. This research focuses on receptors, ion channels, transporters and the mechanism(s) by which they are regulated. The Xenopus oocyte system is used for functional expression of plant mRNA. The source of mRNA is guard cells because they play a critical role in controlling water loss and gaseous exchange. V. faba is the experimental plant choice because research on ion channel and signal transduction of V. faba guard cells is extensive. The two electrode voltage clamp (TEVC) technique is used for the assay. Preliminary results have shown that oocytes injected with V. faba guard cell mRNA (GC mRNA) express a GC specific ABA receptor that inhibits activity of the inward rectifying K + channel, KAT1. This research will test the hypothesis that: ABA modulation of KAT1 is via an extra-cellular facing plasma membrane receptor. A cDNA clone for this receptor will be isolated. The identification of a GC-specific ABA receptor will lead to the identification of one sub-type of the ABA receptor. It may be possible by conservation of homology among receptors to isolate the other subtypes. Sequencing information from the isolated clones will allow use of bioinformatics to identify other proteins in the databases with related functions. The long-term goal of this research is to understand how ABA controls ion uptake during the exchange of water and carbon dioxide in photosynthesis. The research outlined will permit student training in molecular biology, electrophysiology and bioinformatics. The identified plant genes will provide targets for genetic modification and herbicide or chemical manipulation of plant function, thus allowing plants to survive in inhospitable environmental conditions.