###### Abstract  
The 'Lilly of the Valley' species, _Conwallaria_, is renowned for its fragrant white flowers and distinctive fresh and green floral scent, attributed to a rich composition of volatile organic compounds (VOCs). However, the molecular mechanisms underlying the biosynthesis of this floral scent remain poorly understood due to a lack of transcriptomic data. In this study, we conducted the first comparative transcriptome analysis of _C. keiskei_, encompassing the leaf, flower, and root tissues. Our aim was to investigate the terpene synthase (TPS) genes and differential gene expression (DEG) patterns associated with essential oil biosynthesis. Through de novo assembly, we generated a substantial number of unigenes, with the highest count in the root (146,550), followed by the flower (116,434) and the leaf (72,044). Among the identified unigenes, we focused on fifteen putative _ckTPS_ genes, which are involved in the synthesis of mono- and sesquiterpenes, the key aromatic compounds responsible for the essential oil biosynthesis in _C. keiskei_. The expression of these genes was validated using quantitative PCR analysis. Both DEG and qPCR analyses revealed the presence of _ckTPS_ genes in the flower transcriptome, responsible for the synthesis of various compounds such as geraaniol, germacrene, kaurene, linalool, nerolidol, trans-cimene and valencene. The leaf transcriptome exhibited genes related to the biosynthesis of kaurene and trans-cimene. In the root, the identified unigenes were associated with synthesizing kaurene, trans-cimene and valencene. Both analyses indicated that the genes involved in mono- and sesquiterpene biosynthesis are more highly expressed in the flower compared to the leaf and root. This comprehensive study provides valuable resources for future investigations aiming to unravel the essential oil-biosynthesis-related genes in the _Conwallaria_ genus. transcriptome; differential gene expression; floral volatile; monoterpens; sesquiterpenes 202  
depends on two independent pathways: the mevalonic acid (MVA) pathway and the methylerythntrol phosphate (MEP) pathway [9]. The MVA pathway mainly involves the biosynthesis of sterols, sesquiterpenes and triterpenes, while the MEP pathway involves mono- and diterpene biosynthesis in plants [10]. The ample catalytic versatility of terpene synthase (TPSs) in plants accounts for the vast variety of volatile terpenoids. The terpene synthases are able to synthesize multiple products from premyl diphosphate precursors, including geranyl pyrophosphate (GPP), farnesyl diphosphate (FPP) and geranylgeranyl diphosphate (GGPP) [11]. Various _TPS_ genes associated with floral scent biosynthesis have been progressively reported in _Citrus sinensis_[12], _Dancus carota_[13], _Camellia sinensis_[14] and _Lathyrus odoratus_[15]. The TPS family genes represent medium to large-sized families, with almost all plant species containing approximately 20-150 TPS-like functional genes [16]. Based on a systematics analysis, TPS is divided into seven subfamilies: TPS-a, b, c, d, e/f, g and h classes [16]. TPS-b encodes terpene synthase with an R(R)X8W motif that acts as an isomerization catalyst in angiosperms. TPS-c and TPS-g are ancestral synthases in gymnosperm that synthesize mono-, di-, and sesquiterpenes. Laurene synthase is required to produce gibberellic acid under the TPS-e/f class [17]. Additionally, TPS-g encodes for monoterpenes lacking the R(R)X8W motif; this type of TPS produces acyclic monoterpenes contributing to floral VOCs. Several studies have used genome-wide approaches to uncover TPS in rice, _Arabidopsis_, grapes, carrots, apples, eucalyptus, tea tree and tomatoes [18; 19; 20; 21; 22; 23; 24]. The Asparagaceae family belongs to the flowering plants within the Asparagales order of the monocots [25]. _Convallaria_ is a small genus of monocotyledons in the subfamily Nolinoideae that comprises three species: _C. keiskei_, _C. majalis_, and _C. montana_[26].