草莓采后高氧介导微管蛋白表达机理研究

Tubulin is the direct target of peptides in biological cell apoptosis. The high oxygen, low oxygen or high carbon dioxide treatment could regulate postharvest senescence of fruit and vegetable, especially the expression level of proteomics. However, the short-term treatment of high oxygen is quite simple and effective. In the present study, the classic non-climacteric fruit, strawberry, was treated by 80%-100% O2 for 1-24h, and the up-regulated or down-regulated expression level of tubulin was monitored, in order to get the variable role of oxygen concentration and time; the polymerization-depolymerization processes and dynamics of tubulin were studied, and the possible phosphorylation modification and its secondary structure were investigated in strawberry. The correlations between the above and microstructure as well as quality parameters of strawberry were also calculated in order to build and verify a dynamic simulation of ‘high oxygen – tubulin expression – avoiding cell senescence’. Three ‘combinations’ strategy was used in this study to elucidate the molecular mechanism of tubulin expression in cell senescence regulated by high oxygen for a short time. This study could help develop an environmental and green preservative technology as well as research a ‘proteomics to preservative’ on a molecular basis, which is of great insignificance and provide the evidence for high oxygen theory.

微管蛋白是生物细胞凋亡多肽作用的直接靶点。高氧、低氧和高二氧化碳等均可调控果蔬采后衰老，特别是相关蛋白质组表达，其中高氧短时处理更加简易实用。本项目以经典非呼吸跃变型果实草莓为试材，研究80%–100%高氧短激1-24h对草莓微管蛋白差异表达水平的调控作用，发现高氧调节微管蛋白表达上调或下调的作用变量；研究高氧对微管蛋白聚合-解聚动力学特性的介导效用，并预测微管蛋白可能的磷酸化修饰及其二级结构；结合草莓细胞衰老的超微结构及品质参数变化，进一步量化分析各参数和变量之间的相关性，构建“高氧介导→微管蛋白表达调控→延迟或回避果实细胞衰亡”动态模拟理论并进行验证。本研究采用“三结合”技术策略，旨在从分子生物学水平揭示细胞衰老过程中微管蛋白的表达机理，对开发低碳、绿色的果蔬保鲜措施，具有非常重要的意义；基于分子水平为Proteomics to Preservative研究高氧介导理论提供依据。

以“章姬”草莓（Fragaria×ananassa, Duch. Akihime）为试材，研究高氧处理对草莓果实采后品质和蛋白质组表达模式的影响。草莓采后采用不同可控气调（90% O2、3% O2/5% CO2、空气对照）处理并贮藏于0℃低温下，定期监控草莓采后感官和风味品质，并运用高通量定量蛋白质组学以探究高氧对草莓品质代谢和微管蛋白表达的调控作用。研究结果表明：与对照和低氧高二氧化碳气调相比，90%高氧可以显著抑制草莓果实腐烂的发生，显著延缓果实硬度的下降，并能够抑制总酚含量下降和有效维持抗氧化能力，而对可溶性固形物、可滴定酸含量的变化无明显影响。顶空固相微萃取和气相色谱质谱联用技术（SPEM/GC-MS）分离鉴定得到40多种香气物质，分为酯类、醇类、酮类、醛类、酸类、烯烃和杂环化合物等，其中高氧处理组的主要香气成分酯类和呋喃酮类含量显著高于对照组。感官评价结果显示高氧处理组的草莓在香气、色泽、甜度等指标中显著高于对照组，说明高氧处理能较好地保持草莓果实的风味和感官品质。通过高通量定量蛋白质组学研究平台筛选受高氧调控的草莓蛋白质，研究高氧对微管蛋白的显著调控作用，进一步研究微管蛋白和草莓品质形成与调控蛋白质表达水平之间的相关性，研究草莓响应高氧短激时微管蛋白的聚合抑制现象和微管的组装过程。综上所述高氧气调在草莓果实采后防腐保鲜尤其是风味品质的保持中具有潜在的应用前景。本项目研究成果发表论文7篇（SCI收录论文6篇，EI收录论文1篇），申请国家发明专利6项，培养在读博士研究生1名、在读硕士研究生1名、本科毕业生1名。