## 4 Discussion  
The Illumina platform has proven to be an effective technology for transcriptomic research on _Lavandula_ (lavender) plants such as _L.__angustifolia_ 'Lady', _L.__latifolia_, and their natural breed _Lavandula_ \(\times\)_intermediate_ 'Grosso' [8], as well as _L.__angustifolia_ 'X-2' [9], and _L.__angustifolia_ 'Mailette' [10]. In this study, in which we used this platform to characterize the transcriptome of _L.__pulsecens_, clustering and assembly of clean reads provided 124,233 unigenes, and on the basis of annotation using multiple databases, we established that _L.__pulsecens_ unigenes showed closest matches with those from _Sesamum indicium_, followed by _Erythanthe guttata,__Vitis vinifera,__Coffea canephon_, _Nicotiana sylvestris,__Beta vulgaris_, and _Salvia milifornliza_. The COG database provides a standard system for estimating the evolution and function of coding proteins at the genome scale, and our COG annotations revealed that a majority of the identified unigenes are associated with the functional categories \"Translation, ribosomal structure and biogenesis, carbohydrate transport and metabolism,\" \"post-translational modification, protein turnover, chaperones,\" \"general functional prediction only,\" and \"signal transduction mechanisms.\" Furthermore, using GO annotation to comprehensively delineate the functions of _L.__pulsecens_ unigenes and their products, we found that the predicted unigenes were grouped into the three major GO categories, namely cellular components, molecular functions, and biological processes, with a majority being associated with cells and cell parts, binding and catalytic activity, and cellular and metabolic processes. With respect to terpene biosynthesis, we identified a total of 14 terpene biosynthetic genes in _L.__pulsecens_ (_LpDXS_, _LpMCT_, _LpMCS_, and _LpHDR_ in the MEP pathway, _LpAACT_, _LpHMGS_, _LpHMGR_, _LpMVK_, _LpPMK_, and _LpMVD_ in the MVA pathway, and _LpIDI_, _LpGPPS_, and _LpSQS_, and _LpGGPP_ in the terpenoid biosynthesis pathway), which were confirmed based on NCBI homology BLAST searches. Furthermore, we established that the expression levels of most of the genes associated with terpenoid biosynthesis were higher in the stems and leaves than in the roots, which was consistent with HPLC results, indicating a higher accumulation of unsolic and oleanolic acids in the stems. The level of _LpSQS_ was particularly higher in stems and leaves, consistent with the high levels of unsolic and oleanolic acids in the stems and leaves, compared with those in roots. These findings are also comparable to those obtained in previous studies, in which it has been demonstrated that overexpression of SQS enhances the production of phytosterols (stigmasterol and beta-sitosterol) and triterpene (ciwuijianosides B, C1, C2, C3, C4, D1, and D2) in _Eleutherooccus senticosus_[32] and phytosterols (stigmasterol, beta-sitosterol, and campesterol) and triterpene (ginsensoside Rb1, Rb2, Rc, Rd, Re, Rf, and Rg1) in _Panax ginseng_[33]. Furthermore, [PERSON] et al. [34] have reported the enhanced accumulation of phytosterol and saikosaponin contents in _Bupleurum falcatum_ following the overexpression of SQS [34], whereas [PERSON] et al. [35] have reported the increased production of ganoderic acids in a submerged culture of _Ganoderma lucidum_ subsequent to the overexpression of SQS [35], and similarly in response SQS overexpression, [PERSON] et al. have observed the enhanced production of phytosterols in a hairy root culture of _Withania coagulans_[36]. Carbohydrates are necessary to provide energy for the plant growth and maintenance and precursors or intermediates for the metabolic process. In particular, previous studies reported that the endogenous sucrose level affects secondary metabolite biosynthesis.