Epidermal root cells as a suitable cell biological model system to unravel PIN2 auxin efflux carrier turnover and differential growth regulation in plants

表皮根细胞作为合适的细胞生物学模型系统来解开植物中 PIN2 生长素外排载体周转和差异生长调节

• 批准号: 233353861
• 负责人: Dr. David Scheuring
• 金额: --
• 依托单位: Arbeitsgruppe Molekulare Pflanzenphysiologie
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/233353861?language=en
• 关键词: Epidermal; root; cells; suitable; cell

The polar distribution of the phytohormone auxin within the plant is crucial for growth, reaction to the environment and for the development of plant organs such as leaves and flowers. Key players in the auxin distribution are auxin efflux carriers of the conserved PIN (Pin-formed) protein family. Developmental and environmental signals (such as gravity and light) are processed by dynamic adjustments in directional vesicle trafficking of the PIN proteins. Among these adjustments are conditional endocytosis and subsequent degradation of PINs in the vacuole. Starting with observations on gravistimulated as well as dark-incubated seedlings, it was demonstrated that a portion of PIN proteins is internalized and sorted into the lytic vacuolar compartment. Further experiments, using pharmacological approaches, PIN2 trafficking to the vacuole was abolished, presumably by interference with pre-vacuolar compartment (PVC) function. Hence, PVC-dependent degradation and therefore down regulation of PIN2 seems crucial for adaptive growth responses, such as gravitropism. However, mechanisms that signal endocytosis and degradation of plasma membrane proteins in plant cells are still poorly understood. Since PIN2 is expressed in roots, a suitable system in this organ has to be established in order to analyze how PIN2 stability affects differential growth regulations. In both primary and secondary roots, the epidermis differentiates in regularly spaced tricho- and atrichoblasts. Trichoblasts display polar outgrowth leading to the formation of root hairs, contributing largely to surface creation for plant-soil interface, while atrichoblasts do not form root hairs.We intend to investigate differential growth regulation by utilizing this easily accessible system of tricho- and atrichoblasts. I propose that growth regulation in the root epidermal cell file is a suitable model to study these fundamental processes on a cellular level. We will particularly assess PIN2-dependent regulation of cellular auxin homeostasis and its contribution to epidermal growth control.

植物激素生长素在植物体内的极性分布对于生长、对环境的反应以及植物器官如叶和花的发育至关重要。生长素分布的关键参与者是保守的PIN（PIN形成）蛋白家族的生长素流出载体。发育和环境信号（如重力和光）的PIN蛋白的定向囊泡运输的动态调整处理。这些调节包括条件性内吞作用和随后的液泡中PIN降解。从观察重力刺激以及暗孵育的幼苗，它被证明，PIN蛋白的一部分被内化和分类到裂解液泡室。进一步的实验，使用药理学方法，PIN 2运输到液泡被消除，推测是通过干扰前液泡区室（PVC）功能。因此，PVC依赖性降解和因此PIN 2的下调似乎对适应性生长反应（如向地性）至关重要。然而，植物细胞中质膜蛋白的内吞和降解的信号机制仍然知之甚少。由于PIN 2在根中表达，因此必须在该器官中建立合适的系统以分析PIN 2稳定性如何影响差异生长调节。在主根和次生根中，表皮分化成规则间隔的毛细胞和无毛细胞。毛细胞显示极性生长，导致根毛的形成，在很大程度上有助于植物-土壤界面的表面创建，而atrichoblasts不形成根毛。我建议根表皮细胞文件中的生长调节是一个合适的模型来研究这些基本过程的细胞水平。我们将特别评估细胞生长素稳态的PIN 2依赖性调节及其对表皮生长控制的贡献。