PBJ | 中国农业科学院毕金峰团队构建“微观代谢组-细胞壁多糖组分-宏观加工品质”体系解析桃果浆品质形成物质基础

桃中共检出1449种代谢物，酚酸类占比最高（264种，18.22%），黄酮类（241种，16.63%）与脂质类（197种，13.6%）次之。四组样本分离清晰（图2A），模型拟合度良好（Q2 > 0.90，图2B）。基于四组间333个差异积累代谢物（图2C）分析，1#、4#、11#中参与果实色泽形成的酚酸与黄酮类代谢物Z值较高；8#中糖类与有机酸Z值显著降低。

3. 不同品种果胶生物合成通路相关核心代谢物筛选

借助KEGG 代谢通路数据库的标准注释体系，成功鉴定得到 40 个目标代谢物。相关性分析（图3A）显示，各代谢物间存在广泛潜在关联，其中D-半乳糖、D-甘露糖、黄素单核苷酸（FMN）、高柠檬酸、衣康酸等9种代谢物与其他代谢物的关联程度最高；糖类、有机酸与黄酮类是四组样本差异的核心代谢物类别。

4. 核心差异代谢物的代谢通路分析

在碳水化合物代谢通路中，各组均存在肌醇消耗现象，伴随阿拉伯糖、半乳糖、甘露糖等中性糖代谢物的差异积累，其中第四组中性糖水平最高；第一组中肌醇代谢更倾向于果胶主链合成，而非中性糖积累；第二组与第四组呈现螯合性果胶结构域相关代谢特征，中性糖含量相对较高，提示果胶生物合成过程中不同结构域存在差异化调控。葡萄糖经糖酵解生成丙酮酸后进入三羧酸循环，产生柠檬酸、苹果酸等中间代谢物；第二组与第四组衣康酸含量较高，其积累特征可反映细胞壁多糖合成的碳通量差异。此外，葡萄糖经糖酵解-莽草酸途径生成酚类物质，第一组二氢槲皮素等呈色代谢物水平较高，第一、二组咖啡酸消耗更为显著。综上，有机酸、糖类及酚类在各组间积累模式差异显著，为果胶结构异质性及果浆理化、流变与色泽特性的差异提供了生化基础（图4）。

论文链接：https://onlinelibrary.wiley.com/doi/10.1111/pbi.70709

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