γ-氨基丁酸对低温胁迫下桃果实蔗糖代谢的影响

Effects of γ-Aminobutyric Acid on Sucrose Metabolism of Peach Fruit Under Stress of Low Temperature

为探讨γ-氨基丁酸(GABA)对低温胁迫下桃果实蔗糖代谢的影响,以湖景蜜露品种水蜜桃为试验试材,采用5 mmol·L-1外源GABA和100μmol·L-1 GABA-T抑制剂(VGB)处理桃果实,比较分析水蜜桃出汁率、GABA含量、可溶性糖含量、蔗糖代谢中间产物以及蔗糖代谢相关酶基因的变化。结果表明,外源GABA处理和GABA复合VGB处理通过提高桃果实贮藏后期内源GABA含量和蔗糖含量,从而有效抑制桃果实在低温贮藏期间冷害的发生。此外,外源GABA处理抑制了贮藏后期蔗糖降解相关酶基因PpSUS5的表达,减缓了桃果实中蔗糖含量的降低速率,从而提高了果实抗冷害的能力。外源GABA复合VGB处理增强了贮藏后期蔗糖合成相关酶基因PpSPS1、PpSPP1和PpSUS3的表达,从而维持桃果实较高的蔗糖含量,抑制果实冷害发生。本研究结果为桃果实采后贮藏保鲜提供了理论依据。

In order to investigate the effects of γ-aminobutyric acid(GABA) on sucrose metabolism of peach fruit under low temperature storage the Hujingmilu peach fruit were treated with 5 mmol·L-1 exogenous GABA and 100 μmol·L-1 GABA-T inhibitor(VGB). The juice yield, GABA content, soluble sugar content, sucrose metabolism intermediates and sucrose metabolism related enzyme genes were analyzed. The results showed that exogenous GABA treatment and GABA combined VGB treatment could effectively inhibit chilling injury of peach fruit during cold storage by increasing the contents of endogenous GABA and sucrose. Exogenous GABA treatment also inhibited the expression of PpSUS5, a sucrose-degrading enzyme gene, and slowed down the reduction of sucrose in peach fruit, thus improving the resistance ability of fruit to cold damage. In addition, exogenous GABA combined VGB treatment enhanced the expression of sucrose synthase-related genes PpSPS1, PpSPP1 and PpSUS3, maintained the high levels of sucrose contents and inhibited the occurrence of chilling injury. The results provided theoretical basis for postharvest storage and preservation of peach fruit.