ABA胁迫诱导茶树富集γ-氨基丁酸的代谢机理研究

项目名称： ABA胁迫诱导茶树富集γ-氨基丁酸的代谢机理研究

项目编号： No.31500566

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 农业科学

项目作者： 陈琪

作者单位： 安徽农业大学

项目金额： 20万元

中文摘要： γ-氨基丁酸不仅具有极高保健功能，还具有协助植物抵御环境胁迫，调节C-N代谢平衡等生理功能，但对于GABA在茶树体内合成途径的相互关系以及胁迫诱导茶树富集GABA过程对氮代谢的调节尚不明确。项目组对前期获得的转录组数据进行挖掘，获得GABA支路和多胺途径上多条序列，发现ABA能显著诱导茶树根和叶部GAD的表达并促进GABA含量的提高。本项目拟在前期研究基础上，通过抑制GAD基因表达和外源饲喂不同氮素底物这两种正反结合的研究手法，对ABA诱导下茶树应激机制及氮代谢进行研究，一方面利用稳定同位素标记底物对GABA两条合成途径的相互关系进行解析；一方面结合代谢组与表达谱的分析方法，筛选出ABA诱导下茶树以GABA为节点的氮代谢过程中的关键含氮化合物和基因，解析氮代谢模式。本研究将明确逆境诱导茶树体内GABA合成的关键途径与调节氮平衡的分子机理，为茶树栽培与资源开发提供科学依据。

中文关键词： 氮代谢；基因表达；胁迫；抗逆性；次生代谢

英文摘要： Gamma amino butyric acid (GABA) a four carbon non-protein amino acid with an amino group attached to γ-carbon instead of α-carbon exists in different organisms including bacteria, plants and animals. A range of physiological and biochemical analyses from previous studies have unraveled the role of GABA and GABA metabolism. GABA metabolism has different functions in plant metabolism including osmotic and pH regulation, pollen tube growth and guidance, bypass of the tricarboxylic acid (TCA) cycle, C:N balance, nitrogen metabolism, and preventing the accumulation of reactive oxygen species under different environmental stress. Moreover, GABA, a well known neurotransmitter in mammalian brain tissues is also suggested to be a signaling molecule in plants. . In the previous work, Some genes about GABA shunt have been screened from the tea whole organ transcriptome database, and which have been induced by abscisic acid then to increase GABA levels in roots and leaves of tea. But the relationship between the two GABA synthesis pathways in tea are unclear, and the role of GABA metabolism in adversity stress responses in relation to the effect of nitrogen metabolism in tea are also unclear. Therefore, we considered that the inhibiting the GAD gene expression and supplying different exogenous nitrogen substrate would be good tools to study the role of GABA in nitrogen metabolism of tea plant in relation to the response of ABA stress. On the one hand, using the stable isotope labeling the substrate clarify the mutual relations between two GABA synthesis ways; On the other hand, together with metabolite and gene expression profiling analysis method, screening key nitrogen compounds and genes response to ABA stress in tea plant, illuminating the nitrogen metabolism model. This study will clarify the regulatory relationship between exogenous stress treatments and enrichment of GABA, then provide scientific basis for further enhance the development and utilization of tea plant resources.

英文关键词： Nitrogen metabolism;Gene expression;Stress;Resistance;Secondary metabolism