Multi-omics analysis reveals shape- and drying-dependent variation in non-volatile terpenoids of Amomum tsao-ko fruits.

Amomum tsao-ko is a valuable medicinal and culinary resource, yet its non-volatile terpenoid composition remains poorly characterized. This study integrated widely targeted metabolomics and transcriptomics to systematically profile non-volatile terpenoids in A. tsao-ko fruits and investigate the impacts of fruit morphotype and drying process. Using UPLC-MS/MS, 157 non-volatile terpenoids were identified, with 147 common across all samples, indicating a stable core metabolome. Fruit shape significantly influenced terpenoid accumulation, with round fruits generally exhibiting higher levels, and Caesalpin J identified as a shape-discriminatory marker. Drying induced profound alterations, promoting glycosylated forms while reducing free sesquiterpenoids and diterpenoids. Isosteviol was exclusively detected in dried fruits, serving as a drying-specific marker. Transcriptomic analysis revealed 49 shape-responsive differentially expressed genes enriched in terpenoid biosynthesis pathways. Weighted gene co-expression network analysis identified a terpenoid-associated module containing key structural genes and transcription factors. These findings provide a foundational chemical and molecular atlas for quality assessment, germplasm innovation, and optimized processing of A. tsao-ko.