低糖野生种与高糖栽培种西瓜果实代谢产物组分差异分析

Variance Analysis of Metabolite Components Between Low Sugar Wild and High Sugar Cultivated Watermelon Fruits

采用高效液相色谱—串联质谱(UHPLC–MS/MS)技术对西瓜5份具有代表性的材料果实进行代谢产物分析,在此基础上选取栽培西瓜高糖材料‘97103’和野生西瓜低糖材料‘PI296341’,利用气相色谱—质谱联用(GC–MS)方法对主代谢产物进行定量分析。从成熟果实中定量鉴定出58种代谢物,其中22种在‘97103’和‘PI296341’间存在显著差异。韧皮部运输的棉籽糖在野生低糖材料果实中大量滞留,而在栽培高糖材料中极少积累。综合差异代谢物及其代谢途径分析发现,高糖材料‘97103’果实在水苏糖、棉籽糖等光合产物卸载途径及蔗糖积累代谢途径上的代谢产物积累较高;而低糖材料‘PI296341’,则在氨基酸代谢、有机酸代谢途径及6–磷酸葡萄糖等糖代谢途径上产物积累较高。这些发现为野生西瓜进化到栽培种果实品质的代谢产物积累和调控提供了重要依据,也可为提高西瓜品质提供指导。

Five representative watermelon accessions were analyzed using UHPLC–MS/MS,and the primary metabolites of the high sugar cultivar‘97103＇and low sugar wild accession‘PI296341＇fruits were quantified using Gas Chromatography–Mass Spectrometery（GC–MS）. A total of 58 metabolites were identified,among which 27 compounds were significantly different. Raffinose content was much higher in the wild accession PI296341 than that in the cultivar 97103 fruits,and very few raffinose remained in the cultivar 97103 fruits. Analysis of differential metabolites and metabolic pathways revealed that cultivar 97103 fruits accumulated more metabolites from photosynthate unloading（raffinose and stachyose）and sucrose accumulating pathways,while the metabolites from the metabolism pathways of amino acids and organic acids and glucose-6-phosphate were the majority in PI296341 fruits. These findings provide important insights into the metabolic evolution from wild to cultivated species. The identification of metabolic properties can provide technical guidance for future improvement of watermelon quality.