## 4 Discussion
Ger D synthase, a tricyclic sesquiterpene using FFP as a substrate, has been reported in various developmental stages, and decreases during flower opening in ylang-ylang flowers [75]. Similarly, rose transcriptome and headspace analyses identified _Ger D_ as a major emission contributing to floral scent [76]. In _Camelia_, _TPS_ gene analysis revealed paralogous copies of _Ger D_ synthase associated with cold assimilation [14]. Therefore, our study indicates the production of geraniol and _Ger D_ compounds as volatile components of _Convallaria_ flowers. Additionally, _ckTPS4_, 5 and 10 were found to be involved in the synthesis of trans-ocimene: acyclic monoterenes that give citrus, green and woody aromas [77]. These genes showed expression in both leaf and flower tissues and play roles in attracting floral visitors and defending against herbivory [78]. _ckTPS13_, identified as nerolidol synthase, utilizes FFP and GPP as substrates to produce acyclic nerolidol and linalool through a bifunctional enzyme in plants [79]. _ckTPS13_ exhibited unique and significant expressions in the flowers, while its distribution in the leaf and root tissues was limited. In _Lilium_, linalool is the primary monoterene responsible for floral scents [77]. On the other hand, (E)-Nerolidol is a sesquiterpene that is abundant in the essential oils of various plants, including _Piper claussenianum_, _Momordia charantia_, _Ginglo biloba_, _Baccharis dracunculifolia_, _Zanthoxylum hyemale_, _Zorniabra siliensis_ and _Swinglea glutinosa_, as well as many flowering plants such as lavender, neroli, lemongrass, tea tree and ginger [80; 81; 82]. It is known for its aroma and possesses antioxidant, pharmacological and biological properties [83]. (E)-Nerolidol is considered an effective insecticide against _Stevia_ (Aphididae) and tea trees (_Pediculus_) [84; 85]. In the leaf tissue, _ckTPS14_ showed significant upregulation in DE analysis and down-regulation in the flower and root tissues of _C. keiskei_. However, quantification studies have revealed its significant expression in the flower and root, and relatively minor expression in the leaf (Figures 6 and 7). _ckTPS14_ has been identified as an \(S\)-linalool synthase in _Magnolia grandiflora_ through genomic characterization studies [86]. Both DEGs and quantification analysis have indicated linalool synthesis in all tissue types. GPP serves as a substrate for _ckTPS14_, producing monocyclic alcohols, including linalool, in _Vitis_ and _Pinus_ spp. [87]. Along with _ckTPS14_ (leaf), _ckTPS6_, 17 and _18_, which represent identical copies of \(S\)-linalool synthase, showed relatively low expression in flowers but contributed to the synthesis of various VOC compounds. Thus, _ckTPS14_ in the leaf and _ckTPS6_, 17 and _18_ in the flower are associated with \(\alpha\)-terpineol biosynthesis in _C. keiskei_. Furthermore, _ckTPS16_, _ckTPS27_ and _ckTPS28_ were identified as Ent-kaur-16-ene synthase A (or Kaurene synthase [KS]), involved in the synthesis of Ent-kaur-16-ene, a diterpenoid and a key enzyme in gibberell acid biosynthesis found in plants, fungi and bacteria [88]. These genes exhibited moderate expression in all _Conwallaria_ tissues, indicating the synthesis of KS. Ent-kaur-16-ene is formed by the catalytic action of ent-KS and ent-copalyl diphosphate (ent-CPP), using GGPP as a substrate through bifunctional diterpene synthase in _Cucurbita maxima_[89; 90]. In the root tissue of _C. keiskei_, _ckTPS7_, representing valencene synthase (VS), exhibited significant expression. VS is a class 1 plant terpene cyclase or synthase that converts FPP into sesquiterpene valencene, which is widely used in perfumes and cosme. However, the quantification analysis of _ckTPS7_ showed significant expression in the flower and negligible expression in the root and leaf tissues of _C. keiskei_ (Figures 6 and 7). The quantification results differed from the DEGs studies. VS, a sesquiterpene compound, has been identified as a significant volatile compound emitted in flowers of _Vitis_ and _Citrus_[74].