Inositol as a regulator of seedling development

肌醇作为幼苗发育的调节剂

• 批准号: 242751175
• 负责人: Dr. Sabine Schneider
• 金额: --
• 依托单位: Abteilung Zelluläre Biochemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/242751175?language=en
• 关键词: Inositol; regulator; seedling; development

The cyclic sugar alcohol inositol plays a central role in various metabolic pathways in plants. Inositol can be derived from glucose via de novo-biosynthesis, but also be imported into the cell or released from the vacuole via inositol transport proteins. Changes in intracellular inositol content, e.g. in biosynthesis mutants, lead to pleiotropic effects such as altered levels of inositol-containing membrane components, affected membrane dynamics and defects in seedling development. Moreover, auxin signalling is impaired by changing the membrane localisation of auxin efflux carriers.Arabidopsis thaliana has three transport proteins for the import of inositol into the cytosol: AtINT2 and AtINT4 in the plasma membrane and AtINT1 in the tonoplast. If the AtINT1 protein, which transports inositol out of the vacuole into the cytoplasm, is missing, these Atint1 seedlings show an inhibition of cell elongation in roots and in etiolated hypocotyls. This only occurs when sucrose is added to the growth medium. Atint1 plants grown on medium without sucrose do not show apparent growth differences compared to wild type, but have increased levels of inositol-containing membrane components. Comparison of Atint1 seedlings with mutant plants defective in inositol biosynthesis revealed that the observed phenotypic differences do not rely on inositol deficiency, but rather on imbalance in intracellular inositol distribution.The aim of this project is to unravel the impact of inositol balance maintained by intracellular inositol transport on plant development. Because inositol is involved in many different processes we will perform various approaches to cope with the pleiotropic effects of altered inositol transport. The collection of metabolites analysed will be extended, e.g. phosphorylated inositols with supposed signalling function in plants will be included.It will be analysed, if sucrose plays a role as nutrimental or signalling molecule.Due to the fact that inositol is involved in various metabolic pathways, expression analysis of genes encoding key enzymes in inositol metabolism will reveal which metabolic pathways are changed in the Atint1 mutant compared to wild type.Localisation of auxin effluc carriers in Atint1 seedlings and use of an auxin response marker that visualises auxin distribution in plants will elucidate a potential connection between missing inositol transport and auxin signalling. Additionally, research will focus on further phenotypic differences of Atint1 plants compared to wild type, e.g. gravitropism, for which a contribution of inositol was already described.

环状糖醇肌醇在植物的各种代谢途径中发挥着核心作用。肌醇可以通过从头生物合成从葡萄糖衍生，也可以通过肌醇转运蛋白输入细胞或从液泡释放。细胞内肌醇含量的变化，例如在生物合成突变体中，会导致多效性效应，例如含有肌醇的膜成分水平改变、影响膜动力学和幼苗发育缺陷。此外，通过改变生长素流出载体的膜定位，生长素信号传导受到损害。拟南芥具有三种将肌醇输入细胞质的转运蛋白：质膜中的AtINT2和AtINT4以及液泡膜中的AtINT1。如果AtINT1蛋白缺失，AtINT1蛋白负责将肌醇从液泡转运到细胞质中，那么这些Atint1幼苗就会抑制根部和黄化下胚轴的细胞伸长。仅当将蔗糖添加到生长培养基中时才会发生这种情况。 Atint1 植物在不含蔗糖的培养基上生长，与野生型相比没有表现出明显的生长差异，但含有肌醇的膜成分水平有所增加。 Atint1幼苗与肌醇生物合成缺陷的突变植物的比较表明，观察到的表型差异并不依赖于肌醇缺乏，而是依赖于细胞内肌醇分布的不平衡。该项目的目的是揭示细胞内肌醇维持肌醇平衡的影响植物发育中的运输由于肌醇参与许多不同的过程，我们将采取各种方法来应对肌醇转运改变的多效性影响。分析的代谢物的收集范围将扩大，例如将包括假定在植物中具有信号功能的磷酸化肌醇。将分析蔗糖是否发挥营养或信号分子的作用。由于肌醇参与多种代谢途径，因此对肌醇中编码关键酶的基因进行表达分析代谢将揭示 Atint1 突变体与野生型相比哪些代谢途径发生了变化。Atint1 幼苗中生长素流出载体的定位以及生长素反应标记的使用可视化植物中生长素的分布将阐明缺失的肌醇运输和生长素信号传导之间的潜在联系。此外，研究将集中于 Atint1 植物与野生型相比的进一步表型差异，例如。向地性，肌醇对此的贡献已经被描述。