GABA对盐胁迫促进大麦芽苗酚酸富集的生物信号传导机理

酚酸是谷粒中主要的酚类物质，因其对人体的抗氧化作用正在成为研究热点。盐（NaCl）胁迫可诱导大麦芽苗富集酚酸，γ-氨基丁酸（GABA）作为生物信号分子参与其中，但作用机理不明。本研究将检测NaCl胁迫下GABA合成对大麦芽苗中酚酸组成和含量、及其合成关键酶活性与基因表达的影响，明确GABA在酚酸富集中的作用；考察一氧化氮（NO）和Ca2+作为次级生物信号因子对GABA信号的传导和对酚酸合成的调控作用；运用外加法和内源抑制法确定NO和Ca2+对GABA信号传导的顺序定位；阐明GABA、NO和Ca2+组成的生物信号通路及其对酚酸合成关键酶活性和基因与蛋白表达的调控作用。本项目将在酶学、基因调控、蛋白表达和生物信号四个水平上分别揭示GABA/NO/Ca2+对NaCl胁迫下的大麦芽苗富集酚酸的生物信号传导机理，为研发谷物芽类功能食品提供科学依据和理论支撑。

Phenolic acids are main phenolic compounds in cereal grains. Their antioxidant effect on human body has been becoming a research hotspot. Salt (NaCl) stress can induce accumulation of phenolic acids in barley seedlings. Γ-aminobutyric acid (GABA) is involved in this process as a bio-signal molecule, but its transduction mechanism is still unclear. This study will detect compositions and contents of phenolic acids, their activities and gene expressions of the key enzymes to clarify active mechanisms of GABA in bioaccumulation of phenolic acids as well as its downstream biomessengers of nitric oxide (NO) synthesis and Ca2+ transmembrane under the stress. It will also adopt methodologies of both external additive and endogenously inhibitor substances to investigate functions and efficiencies of NO and Ca2+ on GABA signal transduction and the order of their downstream biomessengers. Thus, it will enable us to elucidate their interactive bio-signaling pathway and regulatory effects on relevant gene and protein expressions for bioaccumulation of phenolic acids. This study will reveal transduction mechanisms of GABA/NO/Ca2+ signals in bioaccumulation of phenolic acids under salt stress at four levels of biological enzymology, gene regulation, protein expression and bio-signal transduction, respectively. As a result, it will provide a scientific basis and theoretical support to the development of the germinated- grain food with healthy functions.