Functional analysis of the FORKED and FORKED-LIKE proteins and their role in the environmental control of leaf vein pattern

FORKED和FORKED-LIKE蛋白的功能分析及其在叶脉模式环境控制中的作用

• 批准号: RGPIN-2017-04381
• 负责人: Schultz, Elizabeth
• 金额: $ 2.04万
• 依托单位: University of Lethbridge
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=664549
• 关键词: Functional; analysis; FORKED; LIKE; proteins

Plants are exposed to a constantly changing environment from which they cannot escape. Instead, they alter development to produce a form better adapted to the new environment. The hormone auxin controls many important events in plant development such as defining where leaves form, where shoots and root branch and turning roots towards gravity. Auxin is directionally transported from cell to cell dependent upon the polar localization of PINFORMED (PIN) transport proteins to a particular side of the cell membrane. Many of the environmental responses of plant growth are achieved by changing PIN localization and hence cell polarity, tissue growth and organization.*** I am interested in the formation and organization of leaf veins, which also depends on polar localization of PIN within cells that will become veins. My group discovered the FORKED1 (FKD1) gene, that is important for localizing PIN within these cells. If the gene is mutated, PIN is never localized to the top side of cells, and rather than meeting to form the normal closed loops, the veins form an open, “forking” vein pattern. We found that FKD1 works in the secretory pathway, taking the PIN protein to the plasma membrane. I propose to use FKD1 to study other factors that direct proteins to the top side of cells, a previously proposed pathway that is little understood. *** FKD1 is in a gene family unique to plants and found in all plant genomes. The gene first appears in non-vascular liverworts, indicating that its function predates veins. A mutant that knocks out four members of the Arabidopsis gene family has short roots that do not respond to gravity and misshapen, lumpy leaves. Microscopic observation reveals that the bumps and hollows contain patches of randomly oriented cells. Cells in leaves are normally polarized with their long ends parallel to the midvein. While botanists have suggested that auxin might polarize the cells within the leaf, no one has been able to test the idea experimentally. The mutants provide a unique tool to explore the mechanism by which leaf cells are polarized.*** Vein pattern changes in response to the environment. For example, drought conditions cause a higher vein density with more joints, an adaptation that helps plants maintain photosynthesis. Interestingly, members of the gene family have sequences that suggest regulation by drought and the stress hormone ABA, and my students have shown that FKD1 responds to ABA. As well, mutation to FKD1 or other gene family members eliminates the vein pattern response to drought. Therefore, I propose that the gene family allows vein pattern adaptation to stress, through its regulation by stress-signaling pathways including ABA, and have designed experiments to test this idea. *** By revealing novel processes that achieve PIN localization and cell polarity and defining how the environment influences these processes, my research will allow manipulation of plant form better suited to the environment.

植物暴露在不断变化的环境中，它们无法逃脱，相反，它们会改变发育以产生更好地适应新环境的形式，生长素激素控制着发育过程中的许多重要事件，例如决定植物叶的形成、芽和芽的形成。植物生长素的定向运输依赖于 PINFORMED (PIN) 转运蛋白到细胞膜特定一侧的极性定位。植物生长的许多环境反应都是通过改变 PIN 来实现的。定位和细胞极性、组织生长和组织。*** 我对叶脉的形成和组织感兴趣，这也取决于将成为叶脉的细胞内 PIN 的极性定位。我的小组发现了 FORKED1 (FKD1) 基因，这很重要。如果基因发生突变，PIN 永远不会定位在细胞的顶部，静脉不会形成正常的闭环，而是形成开放的“分叉”静脉模式。 FKD1 在分泌途径中发挥作用，将 PIN 蛋白带到质膜上，我建议使用 FKD1 来研究将蛋白质引导至细胞顶部的其他因子，这是之前提出的途径，但人们对 FKD1 知之甚少。植物特有的基因家族，存在于所有植物基因组中，该基因首先出现在非维管植物中，表明其功能早于静脉，该突变体敲除拟南芥基因家族的四个成员，其根部较短。对重力和畸形、块状的叶子没有反应。 显微镜观察显示，叶子中的凸起和凹陷含有随机定向的细胞斑块，其长端平行于中脉，而植物学家认为生长素可能会使细胞极化。在叶子中，没有人能够通过实验测试这一想法。突变体提供了一种独特的工具来探索叶子细胞的极化机制。*** 例如，干旱条件会导致叶脉模式发生变化。更高的静脉密度和更多的关节，这种适应有助于植物维持有意义的光合作用，该基因家族的成员具有表明干旱和应激激素 ABA 调节的序列，并且我的学生已经证明 FKD1 对 ABA 也有反应。 FKD1 或其他基因家族成员的突变消除了静脉模式对干旱的反应，因此，我提出该基因家族通过包括 ABA 在内的应激信号通路的调节，允许静脉模式适应应激，并设计了实验来验证这一想法。 。 *** 通过揭示实现 PIN 定位和细胞极性的新过程，并定义环境如何影响这些过程，我的研究将允许操纵植物形态，使其更适合环境。