外源褪黑素对低温胁迫下桃果实蔗糖代谢的影响

为探究外源褪黑素减轻桃果实低温冷害发生的机制,以湖景蜜露水蜜桃果实为材料,研究了100μmol·L~(-1)外源褪黑素处理对桃果实采后4℃贮藏期间可溶性糖含量及蔗糖代谢相关酶基因表达的影响。结果表明,100μmol·L~(-1)外源褪黑素能显著减轻果实冷害的症状,保持较高水平的蔗糖和葡萄糖含量。RT-q PCR分析表明,外源褪黑素处理抑制了蔗糖代谢相关酶基因Pp SPS3、Pp SPP1、Pp SUS1、Pp SUS5、PpHK1、Pp FK1和Pp FK3的表达,提高了蔗糖合成相关酶基因Pp SPS1、Pp SPS2、Pp SUT1和Pp NI1的表达水平,维持果实较高的蔗糖和葡萄糖含量,从而提高了桃果实的抗冷性和贮藏品质。本研究结果为揭示外源褪黑素减轻桃果实低温冷害发生的机制提供了新的思路。

Effect of Exogenous Melatonin on Sucrose Metabolism in Peach Fruit Exposed to Low Temperature Stress

In order to explore the mechanism of exogenous melatonin for chilling tolerance induction in postharvest peach fruit,the sugar contents and enzymes gene expression related to sucrose metabolism of Hujingmilu (Prunus persica L.Batsch.) fruit treated with 100 μmol · L-1 melatonin and stored at 4℃ were investigated.The results showed that application of melatonin with the concentration of 100 μ mol· L-1 can significantly reduce the chilling injury of peach fruit after harvest.Peaches treated with 100 μmol· L-1melatonin represented higher levels of glucose and sucrose than the untreated peaches.In addition,melatonin treatment inhibited the expression of sugar metabolism related genes,such as PpSPS3,PpSPP1,PpSUS1,PpSUS5,PpHK1,PpFK1 and PpFK3,and enhanced the expression of sugar synthesis related genes,including PpSPS1,PpSPS2,PpSUT1 and PpNI1 during storage.The chilling tolerance and storage quality of harvested peaches induced by melation treatment are associated with higher levels of sucrose and glucose.These results revealed that melatonin reatment could be used as a useful technique to alleviate chilling injury for coldstored peach fruit.