Spatiotemporal Metabolome analysis reveals a metabolic network during development of the waxy sorghum landrace 'Hongyingzi'

Waxy sorghum is widely utilized in the production of commercial brewing products in China. However, the variations in metabolic profile across its whole life cycle have not been characterized, though several studies have been conducted in certain tissues. This study aims to systematically map the dynamic metabolic landscape and identify the key regulatory nodes across the complete developmental trajectory of a representative waxy sorghum landrace.

This study systematically analyzed the accumulation patterns of metabolites across different developmental stages of 'Hongyingzi', a waxy sorghum landrace. Samples of fifteen tissues were collected at eight key developmental stages.

Broad metabolomics identified 1,324 metabolites belonging to 12 distinct classes. Tissue-specific metabolic profiling revealed that stems and grains at early developmental stages had high accumulation of phytohormones, whereas the roots contained abundant allelopathicals. Additionally, spikelets and mature grains were enriched with antibacterial alkaloids and a putative nove class of immunostimulatory nucleoside bases, implying that these metabolites are involved in biotic and abiotic stress responses. Integrative analysis of the metabolomic and transcriptomic data resulted in the construction of a metabolic regulation network, which was used to identify the key regulatory genes. For instance, a C-glycosyltransferase gene (CGT) associated with high flavonoid accumulation and its co-expressed MYB transcription factor were identified in leaves, while a phospholipase D gene (PLD) and an MYB transcription factor related to lipid metabolism were detected in roots. The results provide a systematic profile of the dynamic metabolic changes and tissue-specific regulatory mechanisms throughout the life cycle of waxy sorghum, providing valuable resources and insights for understanding the metabolic basis of its key agronomic traits. The network identified can serve as a foundation for future organ-specific chemical defense studies and targeted crop improvement.