PR001304 (Project)

Description:Pollen germination is an essential process for pollen tube growth, pollination, and therefore seed production in flowing plants, which requires energy either from remobilization of stored carbon sources, lipid and starch, or from secreted exudates from stigma. Transcriptome analysis from in vitro pollen germination previously showed 14 GO terms, including metabolism and energy, which are overrepresented in Arabidopsis. However, the global changes of carbohydrate and energy-related metabolites during the transition from mature pollen grain to hydrated pollen, the prerequisite step to pollen germination, is poorly understood in Arabidopsis. In this study, we investigated the differential metabolic pathway enrichment among mature, hydrated, and germinated pollen using untargeted metabolomics analysis. Integration of publicly available transcriptome with presented metabolome data revealed starch and sucrose metabolism was significantly increased during pollen hydration and germination. The alterations in central metabolism focusing on sugar, fatty acids, and lipids were analyzed in detail. Several metabolites, including palmitic acid, oleic acid, linolenic acid, quercetin, luteolin/kaempferol, and ?-aminobutyric acid (GABA), were elevated in the hydrated pollen, suggesting a potential role in activating pollen tube emergence. The metabolite levels of mature, hydrated, and germinated pollen, presented in this work provide insights on the molecular basis of pollen germination.