Chromosome-level genome assembly of Tadehagi triquetrum provides new insights into genome evolution and biosynthesis of tadehaginoside

Tadehagi triquetrum is a shrub or subshrub of the legume family (Fabaceae), subfamily Papilionoideae, characterized by winged leaves resembling a gourd shape  (Fang et al., 2025). It is primarily distributed in southern China, including Yunnan, Guangdong, Guangxi, and Hainan. In the Lingnan region, T. triquetrum is commonly used in traditional Chinese medicine, with the entire plant and its roots serving as medicinal parts. These plant materials are used both as single herbs and in compound formulations to treat a variety of diseases, including colds, hookworm infections, lung abscesses, and other types of inflammation (Tang et al., 2022). Previous studies have identified over 70 secondary metabolites from T. triquetrum, including flavonoids, phenylpropanoids, phenolic compounds, triterpenoids, and steroids (Tang et al., 2022). Notably, Tadehaginoside, a phenylpropanoid compound from this plant, has been identified as its major bioactive component (Zhang et al., 2016). Research has shown that Tadehaginoside exhibits broad biological activities, with potential therapeutic effects for metabolic diseases such as obesity, diabetes, and atherosclerosis (Tang et al., 2014; Zhang et al., 2015; Zhao et al., 2021). However, due to the low content of Tadehaginoside and the difficulty in its extraction, chemical synthesis has not been realized, and its high cost limits its broader therapeutic potential and research. With the development of biotechnology, biosynthesis has gradually emerged as a simpler and more efficient synthesis route due to its highly selective catalytic activity (Tian et al., 2024). To date, the key biosynthetic pathways and core genes of Tadehaginoside have not been identified, limiting the possibility of large-scale production through synthetic biology methods. On the other hand, the Fabaceae family is one of the 34 largest families of flowering plants, comprising 765 genera and nearly 20,000 species worldwide (Zhao et al., 2021). Although genome data for 413 Fabaceae plants have been completed, this still covers less than 1% of the species in the family (144 species) (Yu et al., 2025). Sequencing new species and their genomes helps expand our understanding of biodiversity, species evolution, and ecosystem functions (Davis and Knapp, 2025; Yingmin Zhang et al., 2025; Yongting Zhang et al., 2025). The taxonomic position of the Tadehagi genus has long been controversial, mainly due to its morphological similarity to the Desmodium genus (Fang et al., 2025). Jabbour et al. reconstructed the phylogenetic relationships within the Fabaceae tribe using chloroplast DNA fragments (rbcL, psbA-trnH) and nuclear gene sequences (nrITS-1). Their findings support classifying Tadehagi as an independent genus (Jabbour et al., 2018). However, the phylogenetic tree topology constructed from these two datasets shows significant inconsistencies, indicating that more genetic data are needed to provide new insights into species evolution. In this study, we present the first chromosomal-level genome assembly of T. triquetrum. We further analyzed its genomic characteristics and integrated transcriptomic and metabolomic data to explore and validate the key genes involved in the biosynthesis of Tadehaginoside, providing a solid genetic resource for studying the genomic evolution of T. triquetrum and its potential applications.