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: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=744828
• 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.

植物暴露于不断变化的环境，它们无法逃脱。取而代之的是，他们改变了开发以产生更好适合新环境的形式。马酮生长素控制着植物发育中的许多重要事件，例如定义叶片形成的地方，芽和根分支以及将根部转向重力。生长素定向从细胞转移到细胞，取决于pinformed（PIN）转运蛋白到细胞膜特定侧的极性定位。植物生长的许多环境反应是通过改变销钉定位，从而实现细胞极性，组织生长和组织来实现的。我对叶静脉的形成和组织感兴趣，叶静脉也取决于细胞中销的极性定位，这将成为静脉。我的小组发现了Forked1（FKD1）基因，这对于在这些细胞中定位销钉很重要。如果该基因被突变，则永远不会将PIN定位在细胞的顶部，而不是遇到正常的闭环，而是形成开放的“分叉”静脉模式。我们发现FKD1在秘密途径中起作用，将PIN蛋白带到质膜。我建议使用FKD1研究将蛋白质引导到细胞顶部的其他因素，这是一项以前提出的途径，几乎没有理解。 FKD1处于植物独有的基因家族中，并在所有植物基因组中发现。该基因首先出现在非血管肝脏中，表明其功能呈现静脉。一个突变体淘汰了拟南芥基因家族的四个成员的突变，其根源很短，对重力和散落，块状的叶子没有反应。显微镜观察表明，凸起和空心含有随机定向细胞的斑块。叶片中的细胞通常是极化的，其长末端与Midvein平行。尽管植物学家建议生长素可以使叶片中的细胞两极化，但没有人能够通过实验测试这个想法。突变体提供了独特的工具来探索叶片细胞极化的机制。静脉模式对环境的响应发生变化。例如，干旱条件会导致更高的静脉密度，并具有更多的关节，这是一种帮助植物保持光合作用的适应性。有趣的是，基因家族的成员的序列暗示了干旱和强调同性恋ABA的调节，而我的学生表明FKD1对ABA做出了反应。同样，FKD1或其他基因家族成员的突变消除了对干旱的静脉模式反应。因此，我建议该基因家族通过包括ABA在内的压力信号途径来调节静脉模式适应性，并设计了实验来测试这一想法。通过揭示实现PIN定位和细胞极性并定义环境如何影响这些过程的新型过程，我的研究将使操纵植物形成更适合环境。