Postharvest Biology and Technology ( IF 7 ) Pub Date : 2021-07-03 , DOI: 10.1016/j.postharvbio.2021.111637 Jose M. Barrera-Gavira 1, 2 , Simon D.A. Pont 3 , Jenny A. Morris 1 , Pete E. Hedley 1 , Derek Stewart 2, 3 , Mark A. Taylor 1 , Robert D. Hancock 1
Senescent sweetening results in the accumulation of reducing sugars in potato tubers following extended periods of storage at moderate temperatures used to avoid the separate condition of cold-induced sweetening. It represents a significant problem for the potato processing industry due to the development of dark fry colour and the accumulation of acrylamide in processed products. Previous studies have implicated oxidative stress in the accumulation of reducing sugars in potato tubers over long term storage. However, in the present analysis we found no evidence for a correlation between oxidative stress as estimated from quantification of hydrogen peroxide, lipid peroxidation or activity of redox enzymes and the accumulation of reducing sugars. On the contrary, transcriptional profiling indicated changes in carbohydrate metabolism were associated with the onset of senescent sweetening and qRT-PCR indicated that reduced abundance of transcripts encoding a plastidial glucose-6-phosphate/phosphate translocator was widely observed during sweetening onset in multiple genotypes. Our data suggest that reduction in the capacity of plastids to import glucose-6-phosphate reduces the capacity for starch resynthesis in the stored tuber thereby shifting the metabolic balance towards starch turnover resulting in reducing sugar accumulation.
中文翻译:
马铃薯 ( Solanum tuberosum ) 块茎中的衰老甜味与质体葡萄糖-6-磷酸/磷酸转运子转录物的减少有关
在中等温度下长时间储存后,衰老甜味会导致马铃薯块茎中还原糖的积累,以避免冷诱导甜味的单独条件。由于深炸颜色的发展和加工产品中丙烯酰胺的积累,这对马铃薯加工业来说是一个重大问题。先前的研究表明氧化应激与长期储存马铃薯块茎中还原糖的积累有关。然而,在目前的分析中,我们没有发现通过量化过氧化氢、脂质过氧化或氧化还原酶活性估计的氧化应激与还原糖的积累之间存在相关性的证据。相反,转录分析表明碳水化合物代谢的变化与衰老甜味的开始有关,qRT-PCR 表明编码质体葡萄糖-6-磷酸/磷酸盐转运子的转录本丰度减少在多种基因型的甜味开始期间被广泛观察到。我们的数据表明,质体输入 6-磷酸葡萄糖的能力降低会降低储存块茎中淀粉再合成的能力,从而将代谢平衡转向淀粉周转,导致糖积累减少。