番茄激酶SlOST1调控植物开花时间和干旱应答的分子机理研究

Open Stomata 1 (OST1) 是调节植物ABA信号转导、气孔运动和逆境应答的关键蛋白激酶。申请人近期利用CRISPR-Cas9技术在番茄中敲除SlOST1，发现SlOST1基因敲除植株与野生型相比，不仅对干旱胁迫敏感，而且明显晚花。然而SlOST1参与开花时间和干旱应答调控的作用机理仍不清楚。我们通过磷酸化蛋白质组学筛选SlOST1的磷酸化底物，发现SlOST1能够与两个转录因子 SlVOZ1/2互作并且使其磷酸化。本项目的研究内容包括：SlOST1通过磷酸化修饰对S1VOZ1/2蛋白稳定性、亚细胞定位及转录活性调控的作用机理；利用转录组和染色质免疫共沉淀测序技术(ChIP-seq)系统鉴定S1VOZ1/2调节的靶基因，阐明S1OST1与S1VOZ1/2蛋白间互作在番茄开花时间和干旱应答调控中的分子机制。该研究将为番茄的花期调控和耐旱性状的改良提供新的理论依据。

Open Stomata 1 (OST1) is a key protein kinase that regulates plant ABA signaling, stomatal movement, and stress response. We recently used CRISPR-Cas9 technology to knock out SlOST1 in tomato and found that the SlOST1 knockout plants are not only sensitive to drought stress but also are late flowering compared to wild type plants. However, the molecular mechanism by which SlOST1 regulates the flowering time and drought response remains unclear. We screened candidate substrates of SlOST1 through phosphoproteomics and found that SlOST1 can interact with and phosphorylate two transcription factors SlVOZ1/2. This project aims to elucidate the effects of SlOST1 phosphorylation modification on the stability, subcellular localization, and transcriptional activity of SlVOZ1/2, and to identify the target genes of SlVOZ1/2 by transcriptomics and chromatin immunoprecipitation sequencing (ChIP-seq), as well as to uncover the molecular mechanism of S1OST1 and S1VOZ1/2 interactions in regulating tomato flowering time and drought response. This study will provide a new theoretical basis for improving flowering time and drought tolerance of tomato in future.