The role of Vacuolar Hexose Exporters during Stress Response and Development

植物的亚细胞糖分配在适应发育线索和外部条件方面受到强烈调节。我们已经确定了液泡葡萄糖输出erd6样6 (ERDL6)，它对细胞葡萄糖稳态和种子储备的组成有重要影响。ERDL6的表达在激活液泡葡萄糖池的因素下被诱导，并在触发液泡中葡萄糖积累的条件下减少。因此，在应激条件下，erdl6突变体的空泡葡萄糖水平升高，通过线粒体的葡萄糖通量受损。在拟议的资助期内，我们将进一步阐明ERDL6的特征，包括运输活性模式以及它在响应其他胁迫（渗透/干旱胁迫、抗冻性、光限制）和发育（花粉成熟/萌发、细胞壁组成）过程中与转录和转录后调控（磷酸化）相关的作用。此外，我们将通过对erdl突变体的高通量生长表型分析，分析多个erdl- kos对液泡葡萄糖分配的增强损害，以及测试其他erdl对所描述的erdl6-KO效应的补充，来解决其他erdl在液泡己糖输出中的作用。具有tmts和vha2,3的组合突变体将有助于探索己糖输出体和其他类型的叶绿体转运体的功能网络，这些转运体调节液泡糖分配并决定植物在逆境响应和发育过程中的表现。

Subcellular sugar partitioning in plants is strongly regulated in adaptation to developmental cues and external conditions. We have identified the vacuolar glucose exporter ERD6-like 6 (ERDL6), which has a significant impact on cellular glucose homeostasis and composition of seed reserves. ERDL6 expression is induced in response to factors that activate vacuolar glucose pools and reduced during conditions that trigger glucose accumulation in the vacuole. Accordingly, erdl6 mutants have elevated vacuolar glucose levels and glucose flux across the tonoplast is impaired under stress conditions. In the proposed funding period we will elucidate further characteristics of ERDL6 including the mode of transport activity as well as its role during response to other stresses (osmotic/drought stress, freezing tolerance, light limitation) and during development (pollen maturation/germination, cell wall composition) with respect to its transcriptional and post-transcriptional regulation (phosphorylation). In addition, we will address the role of other ERDLs in hexose export from the vacuole by high-throughput growth phenotyping of erdl mutants, analysis of multiple erdl-KOs for enhanced impairment of vacuolar glucose partitioning, as well as testing complementation of the described erdl6-KO effects by other ERDLs. Combinatorial mutants with tmts and vha2,3 will help to explore the functional network of hexose exporters and other types of tonoplast transporters, which regulates vacuolar sugar partitioning and determines the plants performance during stress response and development.