Institute of Postharvest Technology of Agricultural Products, College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China; College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, Zhejiang 315800, China.
Institute of Postharvest Technology of Agricultural Products, College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China; Key Laboratory of Postharvest Biology of Subtropical Special Agricultural Products, Fujian Province University, Fuzhou, Fujian 350002, China.
Food Res Int. 2023 Nov;173(Pt 2):113415. doi: 10.1016/j.foodres.2023.113415. Epub 2023 Aug 28.
Banana fruit is highly vulnerable to chilling injury (CI) during cold storage, which results in quality deterioration and commodity reduction. The purpose of this study was to investigate the membrane lipid metabolism mechanism underlying low temperature-induced CI in banana fruit. Chilling temperature significantly induced CI symptoms in banana fruit, compared to control temperature (22 °C). Using physiological experiments and transcriptomic analyses, we found that chilling temperature (7 °C) increased CI index, malondialdehyde content, and cell membrane permeability. Additionally, chilling temperature upregulated the genes encoding membrane lipid-degrading enzymes, such as lipoxygenase (LOX), phospholipase D (PLD), phospholipase C (PLC), phospholipase A (PLA), and lipase, but downregulated the genes encoding fatty acid desaturase (FAD). Moreover, chilling temperature raised the activities of LOX, PLD, PLC, PLA, and lipase, inhibited FAD activity, lowered contents of unsaturated fatty acids (USFAs) (γ-linolenic acid and linoleic acid), phosphatidylcholine, and phosphatidylinositol, but retained higher contents of saturated fatty acids (SFAs) (stearic acid and palmitic acid), free fatty acids, phosphatidic acid, lysophosphatidic acid, diacylglycerol, a lower USFAs index, and a lower ratio of USFAs to SFAs. Together, these results revealed that chilling temperature-induced chilling injury of bananas were caused by membrane integrity damage and were associated with the enzymatic and genetic manipulation of membrane lipid metabolism. These activities promoted the degradation of membrane phospholipids and USFAs in fresh bananas during cold storage.
香蕉果实对冷藏过程中的冷害（CI）非常敏感，这会导致其品质恶化和商品价值降低。本研究旨在探讨低温诱导香蕉果实 CI 的膜脂代谢机制。与对照温度（22°C）相比，冷藏温度（7°C）显著诱导了香蕉果实的 CI 症状。通过生理实验和转录组分析，我们发现冷藏温度增加了 CI 指数、丙二醛含量和细胞膜通透性。此外，冷藏温度上调了膜脂降解酶基因的表达，如脂氧合酶（LOX）、磷脂酶 D（PLD）、磷脂酶 C（PLC）、磷脂酶 A（PLA）和脂肪酶，但下调了脂肪酸去饱和酶（FAD）基因的表达。此外，冷藏温度提高了 LOX、PLD、PLC、PLA 和脂肪酶的活性，抑制了 FAD 的活性，降低了不饱和脂肪酸（USFAs）（γ-亚麻酸和亚油酸）、磷脂酰胆碱和磷脂酰肌醇的含量，但保持了较高的饱和脂肪酸（SFAs）（硬脂酸和棕榈酸）、游离脂肪酸、磷脂酸、溶血磷脂酸、二酰基甘油的含量，降低了 USFAs 指数和 USFAs 与 SFAs 的比值。综上所述，这些结果表明，冷藏温度诱导香蕉果实发生冷害是由于膜完整性受损所致，与膜脂代谢的酶促和遗传调控有关。这些活性促进了冷藏过程中新鲜香蕉中膜磷脂和 USFAs 的降解。
