基于LC-MS技术分析褚橙商品成熟与生理成熟时果实内在品质的差异

Analysis of the internal causes of nutrient changes in Citrus sinensis between commercially mature and physiology mature stages on metabolomics based on LC-MS technique

褚橙作为云南特有橙类具有极高的经济和营养价值。为探究褚橙果实生理成熟期间各小分子次生代谢物质变化对果实内在品质的影响,利用液相色谱-质谱联用技术(LC-MS),对褚橙商品成熟期(PR)和生理成熟期(R)果实的代谢特征进行分析。通过PLS-DA模型分析、火山图分析和聚类分析,比较了褚橙果实不同成熟阶段代谢物累积的差异,研究褚橙果实成熟期的代谢基础。商品成熟和生理成熟褚橙果实中共检测到822个代谢物,以商品成熟期果实为对照,共筛选出43个显著差异代谢物,主要分为31种,其中氨基酸及其衍生物6种、黄酮类4种、糖类及其衍生物2种、脂类1种、核酸及其衍生物1种、酚类3种、生物碱类8种、芳香类化合物1种、萜类2种、香料类2种和有机酸及其衍生物1种。其中有29个化合物含量上调,14个化合物含量则显著下调。经KEGG通路分析发现苯丙氨酸代谢途径、果糖和甘露糖代谢、氨基糖和核苷酸糖的代谢、缬氨酸、亮氨酸和异亮氨酸的生物合成、淀粉和蔗糖代谢在商品成熟和生理成熟褚橙果实中呈现显著差异。生理成熟褚橙果实口味的变化可能与品质形成相关代谢物,诸如糖、黄酮、生物碱、氨基酸、酚类和有机酸等的丰度变化有关。本研究结果可为褚橙果实内在品质形成的代谢调控机制及综合利用提供基础数据。

Chu orange(Citrus sinensis L.)is one of most valuable fruit in the Yunnan Province for its high economic and nutritional value.To investigate the effects of changes in mic-molecule secondary metabolites during the physiological maturation period on the intrinsic quality of the fruit,a widely targeted metabolomic analysis of fresh pulps was conducted using liquid chromatography-mass spectrometry(LC-MS)on Chu orange fruits at the commercial ripeness(PR)and physiological ripeness(R)stages.Thefinal differential compounds were analyzed using partial least squares discriminant analysis(PLS-DA),volcano map analysis,and hierarchical cluster analysis(HCA).A total of 822 metabolites were detected in commercially mature and physiologically mature orange fruits.In total,43 differential metabolites belonging to 31 kinds were identified,including amino acids and the derivatives(6 kinds),flavonoids(4 kinds),sugars and the derivatives(2 kinds),lipids(1 kind),nucleic acids and the derivatives(1 kind),phenols(3 kinds),alkaloids(8 kinds),aromatic compounds(1 kind),terpenoids(2 kinds),spices(2 kinds),and organic acids and the derivatives(1 kinds).The contents of 29 compounds were up-regulated,while the contents of 14 compounds were significantly decreased.Differential metabolites were enriched into five crucial pathways,including phenylalanine metabolism,fructose and mannose metabolism,amino sugar and nucleotide sugar metabolism,valine,leucine and isoleuaocine biosynthesis,and starch and sucrose metabolism,which might affect the quality of Chu orange.The changes in the abundance of metabolites such as sugars,flavonoids,alkaloids,amino acids,phenols and organic acids in Chu orange resulted in changes in fruit taste after physiological maturity.This study provides some basic data for metabolic regulation mechanism and a comprehensive utilization of intrinsic quality formation of Chu orange fruit.