## 3 Discussion
The expression levels of these genes in rose petals under different light conditions were measured and correlated with the volatile profiles of the petals. The color and fragrance of rose petals are also regulated by transcription factors (TFs) that modulate the expression of structural genes involved in the biosynthesis of pigments and volatiles. Some of the TFs that play a key role in this process are MYB, bHLH, and WD40 [74]. These TFs form complexes that bind to specific DNA sequences and activate or repress the transcription of target genes [72]. For instance, MYB-TFs regulate anthocyanin and flavonoid biosynthesis by activating structural genes such as _CHS_, _F3H_, _DFR_, _ANS_, and _UFGT_[82]. Similarly, bHLH and WD40 TFs interact with MYB-TFs to regulate anthocyanin biosynthesis by forming MBW complexes [77; 78]. Moreover, _RhMYB1_ is a putative TF that is expressed in aromatic roses but not in non-aromatic roses, suggesting its role in regulating volatile biosynthesis [75]. The expression levels of these TFs in rose petals under different light conditions were analyzed and examined their relationship with the pigment and volatile contents of the petals. The developmental stages of flowers significantly affect the volatile compounds they emit, as previous studies have shown [67; 83; 84]. The fragrant compounds also vary con siderably throughout the flower development. The authors of [85] examined the volatile components of _R. odorata_ and _R. chinensis_ and reported that the flowers with four single petals had higher amounts of total volatile compounds in the first stage of development and then decreased sharply. These results agreed with the findings of the phytochemical investigation. The authors of [86; 87] found a positive correlation between the expression of _DXR_, _DXS_, _LIS_, and _AAT1_ genes and the rate of monoterene biosynthesis pathway in the rose flower. They inferred that higher _DXR_ expression could be associated with higher monoterene accumulation, implying that the _DXR_ gene has a critical role in monoterene biosynthesis in _R. canina_ petals. Other studies explored the link between monoterene content in Artemisia annua and the expression of key genes in the MEP and artemisinin biosynthesis pathway, which is the main monoterene biosynthesis pathway in plants. They used qRT-PCR to verify that the upregulation of the main MEP pathway genes led to more monoterenes in plant tissues. [PERSON] [88] observed changes in the relative gene expression and metabolites of terpenoids and phenylpropanoids compounds during different flower developmental stages in tuberose. This research emphasized the importance of timing the developmental stages when studying the regulation of secondary metabolites. [PERSON] [89] analyzed the expression patterns of artemisinin biosynthesis genes in eight different Artemisia species at three developmental stages. The study detected significant differences in the expression levels of these genes among species and developmental stages. The expression of _FLS_ gene, which catalyzes flavanol synthesis, was higher at the budding stage than at the open-flower stage in both cultivars, while the expression of _ANS_ gene, which catalyzes anthocyanin formation, was higher at the open-flower stage than at the budding stage in the dark pink cultivar, but not in the white cultivar. The differential expression of anthocyanin biosynthetic genes in the petals of _R. canina_ explains the molecular basis of the color variation between the dark pink and white cultivars. Among these genes, _ANS_ was the most significantly upregulated gene in the dark pink petals, indicating its key role in regulating the anthocyanin accumulation in this tissue. This finding offers a valuable target for breeding strategies aimed at improving the anthocyanin production and quality in _R. canina_ and other ornamental plants. Flavanol synthesis is more active in the early stages of flower development, before anthocyanin accumulation, which is consistent with previous studies.