Abstract
BACKGROUND: Amomum tsao-ko is an important aromatic crop used in medicines and food. It can be categorized into three main types based on the fruit shape: long (L), oval (O), and round (R). However, limited information is available on the volatile substances present in differently shaped A. tsao-ko fruits. This study investigated the characteristics and biosynthesis of volatile organic compounds (VOCs) in fresh and dried A. tsao-ko fruits of different shapes using widely targeted volatilomics and transcriptome analyses. RESULTS: In total, 978 VOCs, primarily terpenoids, esters, and heterocyclic compounds, were detected. The number of differentially accumulated volatile organic compounds (DAVOCs) in dried fruits of various shapes was significantly higher than that in fresh fruits, with terpenoids, esters, and heterocyclic compounds accounting for approximately 50% of the total DAVOCs. Notably, α-phellandrene, identified as a shared differential accumulated terpenoid across various fruit shapes, was detected in both fresh and dried fruits. Through transcriptome analysis, 40 candidate genes implicated in the terpenoid biosynthesis pathway were screened. An integrated analysis of the metabolome and transcriptome revealed that the structural genes HMGR-2, TPS7, TPS5-10, TPS21-3, TPS21-5, TPS21-6, TPS21-7, and TPS21-9, along with 81 transcription factors (including 17 NACs, 16 MYBs, 16 AP2/ERFs, 13 WRKYs, 13 bHLHs, and 6 bZIPs), co-regulate the biosynthesis of volatile terpenoids. CONCLUSIONS: This study expands our understanding of the volatile metabolism profile of A. tsao-ko and provides a solid foundation for future investigations of the mechanisms governing fruit quality.