## 1 Introduction  
Terpenoids constitute a vast group of natural compounds, with over 50,000 distinct types identified across a broad spectrum of organisms including plants, bacteria, and invertebrates [1, 2, 3]. These compounds are primarily composed of concatenated C\({}_{5}\) isoprenoid units, with structural variations such as monoterenes (C\({}_{10}\)), sesquiterpenes (C\({}_{15}\)), and diterpenes (C\({}_{20}\)) defined by the number of these isoprenoid blocks [3, 4]. The biosynthesis of terpenoids is facilitated through two principal pathways: the mevalonate (MVA) pathway and the methyl-erythnitol phosphate (MEP) pathway, both of which produce the universal precursors, isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP) [5]. In plants, a large family of structurally related enzymes known as terpene synthases/cyclases (TPSs) orchestrates terpenoid biosynthesis. Typically, TPSs in plastids catalyze the cyclization of substrates such as geranyl/neryl diphosphate (GPP/NPP, C\({}_{10}\); nervl being the cis-isomer of geranyl) to yield monoterpenes, or convert geranylgeranyl/neryl diphosphate (GGPP/NNPP, C\({}_{20}\)) into diterpenes. Conversely, cytosolic TPSs primarily catalyze the transformation of trans/cis-farnesyl diphosphate (\(E\), \(E\)-FPP/\(Z\), \(Z\)-FPP, C\({}_{15}\)) into sesquiterpenpens [6; 7; 8]. However, the specific localization of terpene biosynthesis can vary, with instances of monoterpenes and diterpenes also being synthesized in the cytosol, and sesquiterpenes in the plastids [9; 10; 11]. Given the crucial role of terpen in plant biology, research into TPSs has been extensive. The protein sequence of TPS is characterized by two domains: the N-terminal domain (Pfam ID PF01397) includes the 'RRX\({}_{8}\)W' (R, arginine; W, tryptophan; X, alternative amino acid) motif, and the C-terminal domain (Pfam ID PF03936) provides binding sites for Mg\({}^{2+}\) and Mn\({}^{2+}\)[4; 12]. The C-terminal domain is further divided into \(\alpha\), \(\beta\), and \(\gamma\) domains. The \(\alpha\) domain is a highly \(\alpha\)-helical \"isoprenoid\" or farnesyl diphosphate synthase (FPPS or FPPase) fold, with catalysis mediated via 'DDxxD' motifs using a Mg\({}^{2+}\)-dependent \"ionization-initiated\" mechanism [13]. The \(\beta\) and \(\gamma\) domains are located between a pair of \(\alpha\)-helical double-barrel domains and carry out a \"protonation-initiated\" mechanism utilizing a catalytic 'DxDD' motif [8]. The taxonomy, distribution, and products of TPSs in plants have been well studied (Table 1) [12; 13; 14; 15; 16; 17; 18]. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
\begin{tabular}{c} With ‘RRX\({}_{8}\)W’ \\ motif (the \\ second ‘R’ is \\ not conserved) \\ With conserved \\  
The TPS family is mid-sized and highly diversified in plants. The ancestral TPS was likely a bifunctional Class I and II distrepene synthase producing the ent-kaurene required for phytohormone production [19]. The ancestral TPS genes underwent gene duplication at least twice, leading to three ancient TPS lineages: TPS-c, TPS-e/f, and the remaining TPS (h/d/a/b/g) subfamilies (also called subgroups) [8]. TPS-a is the largest subgroup and expanded after the split of the monocot and dicot lineages [20]. The TPS-c subfamily enzymes CPS (copalyl diphosphate synthase) and KS (ent-kaurene synthase) catalyze the committed steps in gibberell biosynthesis, which governs stem elongation, seed germination, and flowering time across land plants [19]. The evolutionary characteristics of the other subgroups in complex angiosperms have not yet been fully elucidated. TPS families have been extensively studied in diverse plant species, including _Arabidopsis thaliana_ ([PERSON]. [21], tomato (_Solanum Lycopersicum_ L.) [8; 16], grapevine (_Vitis vinifera_ L.) [22], _Eucalyptus grandis_ [PERSON] [23], apple (_Malus domestica_ Borkh.) [24], _Mentha longifolia_ ([PERSON]. [25], common wheat (_Tritcium aestivum_ L.) [26], and Orchidaceae [27], etc.