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Article|01 Oct 2020|OPEN
PpINH1, an invertase inhibitor, interacts with vacuolar invertase PpVIN2 in regulating the chilling tolerance of peach fruit
Xingxing Wang1, Yi Chen1, Shu Jiang1, Feng Xu1, Hongfei Wang1, Yingying Wei1, & Xingfeng Shao1,
1College of Food and Pharmaceutical Sciences, Ningbo University, 315800 Ningbo, China

Horticulture Research 7,
Article number: 20168 (2020)
doi: 10.1038/hortres.2020.168
Views: 51

Received: 22 Mar 2020
Revised: 22 Jul 2020
Accepted: 27 Jul 2020
Published online: 01 Oct 2020

Abstract

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 PpVIN2, 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 PpINH1 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 PpINH1 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.