Metabolite profiling of mangosteen seed germination highlights metabolic changes related to carbon utilization and seed protection

Mangosteen seed is categorized as recalcitrant, becoming inviable if exposed to desiccation and low temperature. However, the molecular mechanism of mangosteen seed germination has not been fully understood. This study profiled the metabolites that were present in germinating mangosteen seeds at different stages (zero, one, three, five, seven and nine days after sowing) using liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS). A total of 38 tentative metabolites were profiled and classified into amino acid, organic acid, sugar, polyol, alkaloid and others. Metabolites identified implied a timed regulation for germination. Sugars as well as amino acids exhibited a declining trend throughout the germination period as they are likely to be utilized for development and growth of seedling. Furthermore, secondary metabolites such as alkaloids, flavonoids, and xanthone presence displayed an increasing trend at the middle of germination period which may provide protection for mangosteen seed against herbivory and stress. In brief, carbon utilization and seed protection associated with the modulation of primary and secondary metabolites, respectively are important metabolic signatures of mangosteen seed germination.