基于叶绿体蛋白质组学和代谢组学解析CO2加富缓解黄瓜干旱胁迫的生理机制

Cucumber (Cucumis sativus L.) is one of the most popular vegetables cultivated in China, and it is very sensitive to drought stress which can lead to serious injury of lipid peroxidation and inhibition of photosynthetic electron transport of cucumber leaves. Our previous studies showed that CO2 enrichment can meliorate plant water status, enhance its photosynthetic property and water use efficiency, and subsequently alleviate the negative effect of drought stress, but lack of deep understanding about substance metabolism. In the present study, two-dimensional difference gel electrophoresis (2D-DIGE) proteomic approach and MALDI-TOF-TOF/MS are used to study the differential expressed proteins of cucumber chloroplast, select the key protein regulated by CO2 enrichment under drought stress, then analyze the protein function, gene encoding and subcellular localization by bioinformatics methods. Meanwhile, GS-MS and HPLC-MS method are used to analyze the metabolomics profiles of cucumber leaves, and based on this profiles the candidate metabolites regulated by CO2 enrichment under drought stress are preliminarily selected. Then CE and HPLC are used to quantitively analyze the candidate metabolites. At last, the biological function of those metabolites and proteins which really play important role in the alleviation of enriched CO2 on drought stressed cucumber will be validated. Based on the above study, it is expected to make a deeper insight into the physiological mechanism that CO2 enrichment alleviating the adverse effects of drought stress on cucumber.

黄瓜是我国栽培面积最大的蔬菜作物之一，对水分状况非常敏感，干旱胁迫导致黄瓜幼苗叶片膜质过氧化损伤严重，光合电子传递过程受抑。本课题组的前期研究结果表明CO2加富可改善黄瓜的水分状况，提高光合性能和水分利用效率，缓解干旱胁迫引起的负面效应，但对其物质代谢机制缺乏深入了解。本项目拟通过荧光差异双向电泳和MALDI-TOF-TOF/MS技术研究黄瓜叶绿体蛋白差异表达，筛选出干旱胁迫下受CO2加富调控的关键叶绿体蛋白，然后利用生物信息学方法，进行差异蛋白的蛋白功能、编码基因以及亚细胞定位分析。同时利用GC-MS和HPLC-MS技术获得黄瓜叶片代谢谱，筛选出干旱胁迫下黄瓜受CO2调控的代谢物质，然后采用CE和HPLC等技术进一步分析关键候选代谢物的含量，明确受CO2调控且发挥功能的关键代谢物，并对其生物学功能进行验证，为系统阐明CO2加富缓解黄瓜干旱胁迫的分子机制奠定基础，具有重要的理论和现实意义。

黄瓜对水分状况非常敏感，干旱胁迫导致黄瓜幼苗叶片膜质过氧化损伤严重，光合电子传递过程受抑。CO2浓度加富可改善黄瓜的水分状况，提高光合性能和水分利用效率，缓解干旱胁迫引起的负面效应。本项目拟通过荧光差异双向电泳和MALDI-TOF-TOF/MS技术研究黄瓜叶绿体蛋白差异表达，筛选出干旱胁迫下受CO2加富调控的关键叶绿体蛋白，然后利用生物信息学方法，进行差异蛋白的蛋白功能、编码基因以及亚细胞定位分析。同时利用GC-MS和HPLC-MS技术获得黄瓜叶片代谢谱，筛选出干旱胁迫下黄瓜受CO2调控的代谢物质，然后采用CE和HPLC等技术进一步分析关键候选代谢物的含量，明确受CO2调控且发挥功能的关键代谢物，并对其生物学功能进行验证，为系统阐明CO2加富缓解黄瓜干旱胁迫的分子机制奠定基础，具有重要的理论和现实意义。. 本项目研究结果表明，黄瓜幼苗会通过调节相关蛋白的表达来对干旱胁迫做出响应，以提高其在干旱环境下的适应能力。CO2加富会通过调节相关蛋白的表达来提高干旱胁迫下的净光合速率、抗氧化能力和渗透调节能力，减轻干旱胁迫造成的光破坏和有毒物质积累，在一定程度上缓解黄瓜的干旱胁迫。CO2加富通过调节黄瓜叶片的相关代谢物和代谢途径，提高叶片光合性能、抗氧化能力和渗透调节能力，以提高黄瓜在干旱环境下的适应能力。外源施加谷氨酸提高了干旱胁迫下黄瓜的光合性能、抗氧化能力和渗透调节能力，验证了CO2加富通过调控谷氨酸含量从而减轻干旱胁迫对黄瓜的伤害。