Liu Juan, Li Qingxin, Chen Junjia, Jiang Yueming
Guangdong Engineering Lab of High Value Utilization of Biomass, Guangdong Provincial Bioengineering Institute (Guangzhou Sugarcane Industry Research Institute), Guangdong Academy of Sciences, Guangzhou 510316, China.
Key Laboratory of Plant Resources Conservation and Sustainable Utilization, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
Foods. 2020 Jul 8;9(7):894. doi: 10.3390/foods9070894.
Chilling injury is especially prominent in postharvest bananas stored at low temperature below 13 °C. To elucidate better the relationship between cell membrane lipids and chilling injury, an untargeted lipidomics approach using ultra-performance liquid chromatography-mass spectrometry was conducted. Banana fruit were stored at 6 °C for 0 (control) and 4 days and then sampled for lipid analysis. After 4 days of storage, banana peel exhibited a marked chilling injury symptom. Furthermore, 45 lipid compounds, including glycerophospholipids, saccharolipids, and glycerolipids, were identified with significant changes in peel tissues of bananas stored for 4 days compared with the control fruit. In addition, higher ratio of digalactosyldiacylglycerol (DGDG) to monogalactosyldiacylglycerol (MGDG) and higher levels of phosphatidic acid (PA) and saturated fatty acids but lower levels of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and unsaturated fatty acids were observed in banana fruit with chilling injury in contrast to the control fruit. Meanwhile, higher activities of phospholipase D (PLD) and lipoxygenase (LOX) were associated with significantly upregulated gene expressions of and and higher malondialdehyde (MDA) content in chilling injury-related bananas. In conclusion, our study indicated that membrane lipid degradation resulted from reduced PC and PE, but accumulated PA, while membrane lipid peroxidation resulted from the elevated saturation of fatty acids, resulting in membrane damage which subsequently accelerated the chilling injury occurrence of banana fruit during storage at low temperature.
冷害在采后贮藏于13℃以下低温的香蕉中尤为突出。为了更好地阐明细胞膜脂质与冷害之间的关系，采用超高效液相色谱 - 质谱联用的非靶向脂质组学方法进行研究。香蕉果实分别在6℃下贮藏0天（对照）和4天，然后取样进行脂质分析。贮藏4天后，香蕉果皮出现明显的冷害症状。此外，与对照果实相比，在贮藏4天的香蕉果皮组织中鉴定出45种脂质化合物，包括甘油磷脂、糖脂和甘油脂，其含量有显著变化。另外，与对照果实相比，冷害香蕉果实中双半乳糖基二酰基甘油（DGDG）与单半乳糖基二酰基甘油（MGDG）的比例更高，磷脂酸（PA）和饱和脂肪酸水平更高，但磷脂酰胆碱（PC）、磷脂酰乙醇胺（PE）和不饱和脂肪酸水平更低。同时，磷脂酶D（PLD）和脂氧合酶（LOX）的较高活性与冷害相关香蕉中 和 的基因表达显著上调以及丙二醛（MDA）含量较高有关。总之，我们的研究表明，膜脂降解是由于PC和PE减少，但PA积累，而膜脂过氧化是由于脂肪酸饱和度升高，导致膜损伤，进而加速了香蕉果实在低温贮藏期间冷害的发生。
