Large-scale metabolome analysis reveals dynamic changes of metabolites during foxtail millet grain filling.

Compared with traditional staple crops, foxtail millet grain is rich in nutrition and beneficial to human health. Foxtail millet is also tolerance to various abiotic stresses, including drought, making it a good plant for growing in barren land. The study on the composition of metabolites and its dynamics changes during grain development is helpful to understand the process of foxtail millet grain formation. In our study, metabolic and transcriptional analysis were used to uncover the metabolic processes that could influence grain filling in foxtail millet. A total of 2104 known metabolites, belonging to 14 categories, were identified during grain filling. Functional analysis of DAMs and DEGs revealed a stage-specific metabolic properties in foxtail millet grain filling. Some important metabolic processes, such as flavonoid biosynthesis, glutathione metabolism, linoleic acid metabolism, starch and sucrose metabolism and valine, leucine and isoleucine biosynthesis were co-mapped for DEGs and DAMs. Thus, we constructed a gene-metabolite regulatory network of these metabolic pathways to explain their potential functions during grain filling. Our study showed the important metabolic processes during grain filling and focused on the dynamic changes of related metabolites and genes at different stages, which provided a reference for us to better understand and improve foxtail millet grain development and yield.