CoCoSF调控的可变剪接在植物冷胁迫下的分子作用机制研究

植物响应低温胁迫的分子机制研究主要集中于基因转录调控，较少涉及RNA可变剪接。我们发现植物在低温胁迫下，可变剪接响应异常活跃：毛果杨和拟南芥在冷处理24小时后，大多数剪接因子(>67%)上调表达，同时涌现出大量新的剪接事件；并且，超过2100个剪接事件发生了显著性差异变化。进一步分析，在毛果杨和拟南芥中筛选到两个保守的、快速响应冷胁迫且持续高表达的剪接因子CoCoSF。申请人推断毛果杨和拟南芥在冷胁迫诱导下具有保守的分子作用机制：剪接因子CoCoSF调控下游基因的可变剪接，产生与冷适应性相关的关键剪接异构体。据此，本项目拟寻找CoCoSF靶RNA及其调控的剪接事件，揭示CoCoSF调控的分子剪接机理，并结合野生型、CoCoSF缺失型突变体和恢复型植株的冷逆境表型差异，阐述CoCoSF在植物低温胁迫下的分子作用机制过程，为培育抗低温作物和林木提供分子理论基础。

The studies on molecular mechanisms of plants in response to low temperature are focused on gene transcription and regulation, and however, little is known about the roles of RNA splicing in the process. In our previous investigation, transcriptome-scale analysis showed that more than 67% of expressed splicing factors in Arabidopsis thaliana and Populus trichocarpa are up-regulated under chilling treatment for 24 hours, novel splicing events emerge in large numbers and especially, the number of differentially AS events is rapidly increased to more than 2100, altogether demonstrating that AS events are largely activated by low temperature in both A. thaliana and P. trichocarpa. Further studies identified two splicing factors of CoCoSF(Conserved and Cold-induced highly expressed Splicing Factors), which are conserved in A. thaliana and P. trichocarpa and quickly responded and continuously induced at a high expression level under chilling treatment. Accordingly, we hypothesize that CoCoSF are involved in the adaptation of plants to low temperature by regulating AS events of cold-resistant transcripts. In the proposal, by high-throughput sequencing and bioinformatics analyses in A. thaliana and P. trichocarpa, we will investigate CoCoSF-regulated AS events and CoCoSF-binding motifs to reveal the molecular mechanism that CoCoSF regulates AS events of transcripts in response to cold stress. Finally, by integrating phenotypes of wildtypes, CoCoSF knockout mutants and reversible mutants under chilling treatment, we will try to decipher the molecular roles of CoCoSF-regulated AS events in response to low temperature, which probably contribute to selecting genotypes with superior performance under low temperature conditions and engineering cold-tolerant crops and trees.