基于生物节律的GABA调控拟南芥开花时间的基因网络解析

Exogenous γ-aminobutyric acid (GABA) could promote early flowering in Arabidopsis. Whole genome microarray and microRNA expression profilings showed that GABA can significantly up-and downregulate the genes related to circadian rhythms which affect the transition from vegetative growth to reproductive growth and the conversion of which is also controled by microRNA. However, the internal control mechanisms have yet to understand. This project intends to clarify the role of exogenous GABA on flowering transition by starting from the data analysis of expression profiles, intervaving the gene regulation networks involving in the flowering time controled by GABA signals. This will be validated by quantitative PCR, by testing the loss-of function or overexpression of the transcription factors on acute responses to GABA which were screened by yeast one-hybrid library. Meanwhile, the project will also focus on the analysis of endogenous GABA mutants and core oscillator elements mutants, with the help of CHIP-seq technology to draw the flowering gene network which links the cardian rhythms responding to GABA signals. The project will also clarify the regulation pathway controled by ath-miR156, a kind of microRNA which is reponsive to GABA. Ath-miR156R maybe interacts with microRNA172 to control the expression of three floral meristerm identify genes (LEAFY, FRUITFULL and APETALA1). The ultimate aim of this project is to form the whole gene network which control the output of flowering time modulated by GABA signals.

外源性γ-氨基丁酸（GABA）能够促进拟南芥的早开花。已有的表达谱和microRNA表达谱的分析表明GABA能够显著上调和下调与昼夜节律相关的基因以及影响营养生长向生殖生长的转换的microRNA的表达。但GABA信号调节开花的内在机制尚未见研究。课题拟从上下调基因的启动子分析入手，用酵母单杂交技术有望筛选到响应GABA的转录因子，并从开花时间进程上阐明外源性GABA调控的基因表达变化；课题通过对GABA含量突变体以及生物钟节律关键基因突变体的研究,用CHIP-seq技术分析由生物节律控制的对GABA信号响应的影响开花的基因，探索GABA信号和生物节律在控制拟南芥开花的基因网络中的内在联系；课题也将通过定量RT-PCR技术、原位杂交等技术分析microRNA水平上调节开花的途径，重点阐明GABA信号响应的ath-miR156调节开花的信号途径，最终形成完整的GABA调控开花时间的基因网络。

外源性γ-氨基丁酸（GABA）能够促进拟南芥的早开花。已有的表达谱和microRNA表达谱的分析表明GABA 能够显著上调和下调与昼夜节律相关的基因以及影响营养生长向生殖生长的转换的microRNA 的表达。但GABA 信号调节开花的内在机制尚未见研究。课题从上下调基因表达变化入手，以qRT-PCR、荧光素标记和细胞成像等技术证实了外源性GABA 对基因表达的调控；课题以GABA合成代谢突变体以及生物钟节律关键基因突变体的研究,分析了生物节律控制的对GABA 信号响应的影响开花的基因，探索了GABA 信号和生物节律在控制拟南芥开花的基因网络中的内在联系，最终形成完整的GABA 调控开花时间的基因网络。课题研究揭示的研究发现和线索奠定了未来5-10年课题深入研究的着力点。