Wang Xingxing, Chen Yi, Jiang Shu, Xu Feng, Wang Hongfei, Wei Yingying, Shao Xingfeng
College of Food and Pharmaceutical Sciences, Ningbo University, 315800 Ningbo, China.
Hortic Res. 2020 Oct 1;7:168. doi: 10.1038/s41438-020-00389-8. eCollection 2020.
Sucrose metabolism, particularly the decomposition of sucrose by invertase, plays a central role in plant responses to cold stress. Invertase inhibitors (INHs) evolved in higher plants as essential regulators of sucrose metabolism. By limiting invertase activity, INHs keep cellular sugar levels elevated, which provides enhanced protection to plants under stress. Our results showed that the expression of , the only vacuolar invertase (VIN) gene in peach fruit sensitive to chilling temperatures, increases significantly during cold storage, while VIN enzyme activity increases more modestly. We also found that peach fruit transiently overexpressing had decreased VIN activity. Interactions of PpINH1 and PpVIN2 with recombinant proteins were shown by yeast two-hybrid assays and bimolecular fluorescence complementation assays, as well as in vitro. During cold storage, trehalose-treated peach fruit had significantly increased expression, decreased VIN enzyme activity, and significantly higher sucrose content than did untreated fruit. As a result, the treated fruit had enhanced resistance to chilling injury. Collectively, our data show that the post-translational repression of VIN enzyme activity by PpINH1 helps maintain sucrose levels in peach fruit during cold storage, thereby improving resistance to chilling injury.
蔗糖代谢，尤其是蔗糖被转化酶分解的过程，在植物对冷胁迫的响应中起着核心作用。转化酶抑制剂（INHs）在高等植物中进化成为蔗糖代谢的重要调节因子。通过限制转化酶活性，INHs使细胞内糖水平升高，从而在胁迫条件下为植物提供增强的保护。我们的结果表明，桃果实中唯一对低温敏感的液泡转化酶（VIN）基因 在冷藏期间表达显著增加，而VIN酶活性的增加幅度较小。我们还发现，瞬时过表达 的桃果实VIN活性降低。酵母双杂交试验、双分子荧光互补试验以及体外试验均表明PpINH1和PpVIN2与重组蛋白之间存在相互作用。在冷藏期间，经海藻糖处理的桃果实 表达显著增加，VIN酶活性降低，且蔗糖含量显著高于未处理的果实。因此，处理后的果实对冷害的抗性增强。总体而言，我们的数据表明，PpINH1对VIN酶活性的翻译后抑制作用有助于在冷藏期间维持桃果实中的蔗糖水平，从而提高对冷害的抗性。
