ABSTRACT
Plant metabolites are important for plant development and human health. Plants of celery (Apiumgraveolens L.) with different-colored petioles have been formed in the course of long-term evolution. However, the composition, content distribution, and mechanisms of accumulation of metabolites in different-colored petioles remain elusive. Using ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), 1159 metabolites, including 100 lipids, 72 organic acids and derivatives, 83 phenylpropanoids and polyketides, and several alkaloids and terpenoids, were quantified in four celery cultivars, each with a different petiole color. There were significant differences in the types and contents of metabolites in celery with different-colored petioles, with the most striking difference between green celery and purple celery, followed by white celery and green celery. Annotated analysis of metabolic pathways showed that the metabolites of the different-colored petioles were significantly enriched in biosynthetic pathways such as anthocyanin, flavonoid, and chlorophyll pathways, suggesting that these metabolic pathways may play a key role in determining petiole color in celery. The content of chlorophyll in green celery was significantly higher than that in other celery cultivars, yellow celery was rich in carotenoids, and the content of anthocyanin in purple celery was significantly higher than that in the other celery cultivars. The color of the celery petioles was significantly correlated with the content of related metabolites. Among the four celery cultivars, the metabolites of the anthocyanin biosynthesis pathway were enriched in purple celery. The results of quantitative real-time polymerase chain reaction (qRT-PCR) suggested that the differential expression of the chalcone synthase (CHS) gene in the anthocyanin biosynthesis pathway might affect the biosynthesis of anthocyanin in celery. In addition, HPLC analysis revealed that cyanidin is the main pigment in purple celery. This study explored the differences in the types and contents of metabolites in celery cultivars with different-colored petioles and identified key substances for color formation. The results provide a theoretical basis and technical support for genetic improvement of celery petiole color.
Subject(s)
Humans , Anthocyanins , Apium/metabolism , Chlorophyll/metabolism , Color , Gene Expression Regulation, Plant , Metabolomics , Plant Proteins/genetics , Tandem Mass SpectrometryABSTRACT
Glucose-6-phosphate dehydrogenase (G6PDH) catalyzes the first and rate-limiting step of the oxidative pentose phosphate pathway, existing in both cytosolic and plastidic compartments of higher plants. Its main function is to provide reducing power (NADPH) and pentose phosphates for reductive biosynthesis and maintenance of the redox state of the cell. In addition, the expression of this enzyme is related to different biotic and abiotic stresses. In this review, we analyzed the isoenzyme, regulation and biological function of G6PDH. Meanwhile, we summarized the progress work of G6PDH involved in stress resistance, gene cloning, enzyme-deficiency and cluster analysis. Problems should be solved were also discussed.