Table_1_Comparative Analysis of Akebia trifoliata Fruit Softening at Different Flesh Ripening Stages Using Tandem Mass Tag Technology.xlsx

Owing to its medicinal and high nutritional values, Akebia trifoliata can be considered as a new type of medicinal and edible homologous resources, and it has begun to be widely cultivated in many areas of China. Over-softening of fruit would affect the sensorial quality, utilization rate, and consumer acceptance of the fruit postharvest. However, fruit softening has not been characterized and the molecular mechanism underlying A. trifoliata fruit softening during ripening remains unclear. A comparative proteomic analysis was performed on the fruit at three developmental stages using tandem mass tag technology. In total, 2,839 proteins and 302 differentially abundant proteins (DAPs) were identified. Bioinformatics analysis indicated that most DAPs were implicated in oxidoreductase activity, protein domain-specific binding and pyruvate metabolism. Moreover, 29 DAPs associated with cell wall metabolism, plant hormone, and stress and defense response pathways were validated using quantitative PCR. Notably, pectinesterase, pectate lyase, and β-galactosidase, which are involved in cell wall degradation, as well as gibberellin regulated protein, cysteine protease, thaumatin-like protein and heat shock proteins which is involved in plant hormone, and stress and defense response, were significantly up-regulated in softening fruit compared with the levels in non-softening fruit. This indicated that they might play key roles in A. trifoliata fruit softening. Our findings will provide new insights into potential genes influencing fruit softening traits of A. trifoliata, which will help to develop strategies to improve fruit quality and reduce softening-related losses.

鉴于三叶木通（Akebia trifoliata）兼具药用价值与较高营养价值，可作为新型药食同源资源，目前已在我国诸多地区实现规模化种植。果实过度软化会显著影响采后三叶木通果实的感官品质、商品利用率及消费者接受度。然而，目前针对该果实软化过程的系统表征尚未开展，其成熟阶段果实软化的分子机制仍有待阐明。本研究采用串联质量标签（tandem mass tag, TMT）技术，对三叶木通果实的三个发育阶段进行了比较蛋白质组学分析。共计鉴定得到2839种蛋白质，以及302个差异丰度蛋白（differentially abundant proteins, DAPs）。生物信息学分析结果显示，大部分差异丰度蛋白参与氧化还原酶活性调控、蛋白质结构域特异性结合以及丙酮酸代谢通路。此外，研究通过定量PCR验证了29个与细胞壁代谢、植物激素及胁迫防御应答通路相关的差异丰度蛋白。值得关注的是，参与细胞壁降解的果胶酯酶、果胶裂解酶与β-半乳糖苷酶，以及参与植物激素调控、胁迫防御应答的赤霉素调控蛋白、半胱氨酸蛋白酶、类甜蛋白与热休克蛋白，在软化果实中的表达水平显著高于未软化果实。上述结果表明，这些蛋白可能在三叶木通果实软化过程中发挥关键调控作用。本研究成果为解析影响三叶木通果实软化性状的潜在基因提供了全新视角，可为制定改善果实品质、降低软化相关损耗的策略提供理论依据。