Lipidomic study reveals the effect of morphological variation and other metabolite interactions on the lipid composition in various cultivars of Bok choy

Bok choy is an important Brassica vegetable which is also known for its wide range of cultivars that differ in their appearance, leaf color, size and shape. For the purpose to investigate the effect of these phenotypic differences on their lipid composition, seven morphotypes of NHCC (Suzhouqing, Aijaohuang, Wutacai, Yellowrose, Ziluolan, Xiangqingcai and Zicaitai) were selected for this study. For this reason, extensive metabolic approach was adopted which was mainly focused on lipidomics. The overall metabolic position of lipids was determined and the isolated lipid compounds were characterized on the basis of their lipid classes. Moreover, discriminative analysis was applied to monitor the distribution pattern of lipid in different cultivars. Aijiaohuang was the leading cultivar which contained highest lipid levels, whereas least proportion was found in Zicaitai. We proposed that leaf color might have an effect on the lipid composition such as purple cultivars were dominated in glycerophopholipids, light green in fatty acids and dark green were rich in glycerolipids. The level of metabolites differed greatly among different genotypes. Lipid-metabolite interactions revealed the positive correlation of lipids with flavonoid and hydroxycinnamoyl derivatives, whereas negative correlation was noticed in case of phenylamines. This is the first comprehensive study based on lipidomics in order to evaluate the substantial impact of various phenotypes on the metabolic composition of NHCC.