PI-PLC介导Ca2+调控鲜切果蔬GABA富集机制研究

磷脂酰肌醇特异性磷脂酶C（PI-PLC）在植物响应逆境胁迫的信号转导中发挥重要作用。我们前期研究发现，机械损伤能诱导鲜切胡萝卜中GABA的富集，且外源Ca2+处理能提高其富集，但其调控机理还不清楚。本课题在前期工作基础上，以草莓和胡萝卜等果蔬为原料，围绕Ca2+与鲜切果蔬中GABA富集关系这一核心问题，从PI-PLC信号传导和GABA代谢途径等方面，研究不同损伤强度、贮藏温度及外源处理对鲜切果蔬Ca2+和CaM含量、GABA积累及代谢途径关键酶活性和基因表达的影响，并通过PLC拮抗剂处理来验证PI-PLC与Ca2+的相互关系，从分子水平上阐明PI-PLC介导的Ca2+信号调控鲜切果蔬GABA富集的作用。本项目不仅可以深入揭示鲜切果蔬中GABA富集的调控机理，同时也为通过采后处理提高鲜切果蔬中的GABA含量，改善产品的营养和功能品质提供依据，具有重要的理论意义和实践应用价值。

Phosphoinositide-specific phospholipase C (PI-PLC) is a ubiquitous molecule that plays important roles in signal transduction in response to a variety of environmental stresses. Our previous work found that rapid accumulation of γ-aminobutyric acid (GABA) occurred after fresh-cut processing, and exogenous CaCl2 treatment significantly enhanced GABA accumulation in fresh-cut carrots. However, the regulatory mechanisms on GABA accumulation are poorly understood. Based on our previous results, the PI-PLC signal transduction and GABA metabolism pathway are concerned. The effects of various wounding intensities, different storage temperatures and exogenous treatments on Ca2+/calmodulin content, GABA accumulation, activities and gene expression of key enzymes in GABA metabolic pathway in fresh-cut fruits and vegetables will be explored, with focus on exploring the relationship between Ca2+ signal and GABA accumulation. Meanwhile, the role of PI-PLC in mediating Ca2+ signal in GABA accumulation will be validated by using antagonist of PI-PLC action. Based on these investigations, the molecular mechanisms of PI-PLC-mediated Ca2+ on regulating GABA accumulation in fresh-cut fruits and vegetables will be elucidated. This attempt will not only facilitate to elucidate the regulation mechanisms of wounding-induced GABA accumulation, but also lay the foundation for increasing GABA content and thereby improving the nutritional and functional quality of fresh-cut produce by means of postharvest techniques.