Analysis of vacuolar sugar transport

液泡中的糖积累对于植物发育和生理学以及农艺学相关性都是非常重要的。然而，到目前为止，尚未在分子水平上鉴定出相应的位于液泡膜的转运蛋白。本研究从拟南芥中首次鉴定出一种液泡膜糖转运蛋白（TMT，tonoplast monosaccharide transporter）。TMT蛋白代表拟南芥中单糖转运蛋白的一个小亚组，包括3种同种型。所有的TMT蛋白都存在于液泡膜中，并表现出独特的分子结构。Attmt1和2基因表现出组织特异性表达模式，并上调后，冷，盐和干旱胁迫或单糖的应用。与Wt植物相比，tmt敲除植物显示出减少的液泡葡萄糖摄取，并且缺乏在冷诱导时积累单糖的能力。在这里，我们想扩展我们的分析TMT蛋白的功能和调节。特别是，我们有兴趣在分析结构决定因素，导致TMT蛋白质的液泡膜定位，我们将破译一个假定的功能，独特的大的位于中央的环域，我们将确定环结合蛋白。此外，液泡糖运输在适应低温的生理影响将澄清使用系统生物学方法。为此，我们将比较相应的代谢，转录组和蛋白质组的变化在野生型植物，在tmt敲除，并在tmt过表达线冷适应。

Sugar accumulation in vacuoles is of high importance for plant development and physiology, as well as of agronomic relevance. However, corresponding tonoplast located transport proteins have not been identified on the molecular level up to now. We identified a first vacuolar sugar transporter (TMT, tonoplast monosaccharide transporter) from Arabidopsis on both, the molecular and functional level. TMT proteins represent a small subgroup of monosaccharide transporters in Arabidopsis comprising 3 isoforms. All TMT proteins reside in the tonoplast and exhibit a unique molecular structure. Attmt1 and 2 genes exhibit a tissue specific expression pattern and are up-regulated upon cold-, salt- and drought stress or monosaccharide application. tmt knock out plants show reduced vacuolar glucose uptake and lack, in contrast to Wt plants, the ability to accumulate monosaccharides upon cold induction. Here we want to extend our analysis on the function and regulation of TMT proteins. In particular, we are interested in analyzing structural determinants leading to a tonoplast localization of TMT proteins, we will decipher a putative function of the uniquely large centrally located loop domain and we will identify loop binding proteins. In addition, the physiological impact of vacuolar sugar transport during adaptation to cold temperatures will be clarified by using a systems biological approach. For this we will compare corresponding metabolic-, transcriptomic- and proteomic changes in Wt plants, in tmt knock out-, and in tmt overexpressor lines upon cold adaptation.