TODL1在植物株型建成和生殖发育中的功能研究

鞘脂既是细胞膜系统的重要组成成分，也参与细胞信号传导。神经酰胺和鞘氨醇-1-磷酸（sphingosine-1-phosphate, S1P）是两类重要的鞘脂信号物质。神经酰胺酶能够将神经酰胺水解成鞘氨醇和脂肪酸，而鞘氨醇则可以在激酶的作用下被磷酸化生成S1P，因此神经酰胺酶作为一个关键酶在神经酰胺和S1P信号通路中扮演重要角色。我们前期的研究结果证明TOD1基因编码一个碱性神经酰胺酶，在调控植物细胞的膨压过程中起关键作用。拟南芥At4G38500（TODL1）基因与TOD1同属一个进化分支，它编码一个叶绿体定位的蛋白，该基因的纯合突变体植株矮化、育性严重下降。本课题将对突变所造成的表型进行深入研究，并通过转录组、鞘脂组学等方法探讨叶绿体与细胞核之间的逆行信号以及鞘脂类物质与植物激素之间的相互作用。本研究结果将有助于深入了解鞘脂类物质调控植物株型建成和生殖发育的分子机制。

Sphingolipids are essential for membrane structure and are also involved in signal transduction. Ceramide and S1P (sphingosine-1-phosphate) are two classes of well-studied bioactive sphingolipids. Ceramidases hydrolyze ceramide to yield sphingosine and fatty acid, and sphingosine can be phosphorylated by sphingosine kinases to form S1P. Therefore, ceramidase plays key role in ceramide and S1P mediated signaling pathways. Our previous study showed that TOD1 is a bona fide alkaline ceramidase which plays a key role in turgor pressure regulation in plant cells. AT4G38500 (TODL1), which belongs to the same subfamily of TOD1 in Arabidopsis, encodes a chloroplast localized protein. The mutation of TODL1 leads to dwarf and sever reduced fertility phenotype. In this project, we will study the detailed phenotype of the mutant. The transcriptomics and sphingolipidomics analyses will be applied to further unveil the retrograde signaling from chloroplast to nucleus and interaction between sphingolipids signaling and plant hormone signaling. The results of this study will provide insights into the molecular mechanism of sphingolipids controlling plant architecture and reproduction.