ABSTRACT We previously reported that the acid invertase gene PpVIN2 appears to be induced by chilling and may play an important role in sucrose metabolism in peach fruit subjected to cold storage. We also hypothesised that an invertase inhibitor (INH) affects vacuolar acid invertase (VIN) activity at the post-translational level. To determine which INH gene correlates with VIN activity, five INH genes (designated PpINH1–5) were identified and cloned from ‘Yulu’ peach. Relative expression for each gene was then measured in ‘Yulu’ peaches stored at 0, 5, 10, and 20°C and in ‘Hujingmilu’ peaches stored at 5°C. Each INH gene contains four conserved cysteine residues and four asymmetric alpha-helices characteristic of inhibitor protein. PpINH1–4 are members of the INH family while PpINH5 is classified as a pectin methylesterase inhibitor (PMEI). Transcript analyses showed that the PpINHs in ‘Yulu’ peaches have lower expression during storage at 5°C vs. 10°C, indicating that they are not low temperature-induced genes. However, PpINH1 expression is negatively correlated with VIN activity in both ‘Yulu’ and ‘Hujingmilu’ peaches stored at 5°C, suggesting PpINH1 is involved in the post-translational regulation of VIN under chilling conditions.

中文翻译：

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假定转化酶抑制剂基因的克隆、分子特征和表达及其与桃果实液泡酸性转化酶活性的潜在关系

摘要 我们之前报道过，酸性转化酶基因 PpVIN2 似乎是由冷藏诱导的，并且可能在受冷贮藏的桃果实的蔗糖代谢中起重要作用。我们还假设转化酶抑制剂 (INH) 在翻译后水平影响液泡酸转化酶 (VIN) 活性。为了确定哪个 INH 基因与 VIN 活性相关，从“玉露”桃中鉴定并克隆了五个 INH 基因（指定为 PpINH1-5）。然后测量了在 0、5、10 和 20°C 下储存的“玉露”桃子和在 5°C 下储存的“胡井蜜露”桃子中每个基因的相对表达。每个 INH 基因包含四个保守的半胱氨酸残基和四个不对称 α-螺旋特征的抑制剂蛋白。PpINH1-4 是 INH 家族的成员，而 PpINH5 被归类为果胶甲酯酶抑制剂 (PMEI)。转录分析表明，'玉露'桃中的 PpINHs 在 5°C 和 10°C 下储存期间表达较低，表明它们不是低温诱导基因。然而，PpINH1 表达与 '玉露' 和 '胡井蜜露' 桃在 5°C 下储存的 VIN 活性呈负相关，表明 PpINH1 参与了低温条件下 VIN 的翻译后调控。