## 2 Results and Discussion
### Secoriridoids-Related Biosynthetic Genes Expression Profiles in Response to Wounding
The highest increase was recorded for _CeSLS_ 48 HAW, where its expression was approximately 800 fold higher than in the respective control. No statistically significant differences between LL and SL were determined (Figure 2). Namely, factorial ANOVA revealed that time is the only factor which has a significant impact on the expression of analyzed genes upon wounding (\(p<0.05\)), while differences between LL and SL did not contribute to the obtained differences in gene expression (\(p>0.05\)). The observed increase in the relative expression of SGs biosynthetic genes was in accordance with the detected increase of total iridoids (principally SGs) content in leaves. The expression patterns of these genes showed a noticeable decrease 96 HAW (Figure 2). Close examination of single genes revealed that _CeSLS_ expression, although following the expression pattern of other SGs-related genes, was already elevated 2 HAW in both SL and LL, with statistically significant enhancement 48 HAW. Similar to our results, the expression of _SLS_ and _LAMT_ genes in _C. roseus_ was found to be significantly up-regulated 6 h, 8 h, and 24 h after the _M. sexta_ larvae attack and wounding of leaves. However, the expression of genes that were related to the early steps up to the _7 DLH_ did not display such a high induction [25]. Significant induction of _SLS_ transcripts in response to wounding was also recorded in _C. roseus_ 6 h after damaging of \(\sim\)50% of the leaf lamina with a surgical blade [54]. [PERSON] et al. [42] also showed that expression level of _SLS_ was largely up-regulated in _C. roseus_ 24 h after wounding of leaves with a surgical blade, together with some other TIA biosynthesis genes (_STR_ and _PX1_). Plants act in response to either wounding or herbivore attack by triggering complex signaling pathways, whereas the synthesis and perception of JA and its derivatives are considered to be of key importance [28; 29; 55; 56]. Endogenous JA levels promptly increase upon wounding, in damaged as well as in non-damaged distal tissues [48; 55; 57]. The increased JA levels are perceived via COI/JAZ co-receptor complex, whereby COI ubiquitinates JAZ transcription repressors. Subsequently, JAZ degradation releases JA-responsive transcription factors (TFs) and activates wound-induced gene expression [58]. In _C. roseus_, the expression of MIA structural and regulatory genes are mainly JA-responsive, with COI1, MYC2, and JAZs representing the crucial elements of the JA signaling pathway [33]. Transcription factor CrMYC2, which belongs to the IIle subgroup of bHLH TF, is a master regulator that activates CrORCAs (directly ORCA2 and ORCA3), the AP2/ERF family transcription factors, thus leading to the induced expression of several MIA biosynthetic genes [29]. In addition to MYC2, another two JA-inducible bHLH transcription factors, BIS1 and BIS2, from clade IVa, have proven to be specifically involved in iridoid branch of MIA biosynthesis in _C. roseus_[30; 31]. The overexpression of _CrBIS1_ or _CrBIS2_ leads to the increased expression of iridoid pathway genes and early MEP pathway genes, as well as to the increased accumulation of TIAs [28; 30; 31]. Both of the genes are specifically involved in the iridoid branch and are under control of an amplification loop [28]. It is accepted that these two TFs are involved in the regulation of the structural genes expression in _C. roseus_ that MYC2/ORCA3 cascade cannot cover [31; 39]. Conversely, JAM1 and its homologues, JAM2 and JAM3, are negative regulators of MYC-like TFs and JA responses. These TFs, which belong to the subgroup IIId of bHLHs, most likely interfere with or block the binding of MYC-like TFs to the JA-responsive genes' promoters [32; 56]. Based on the presented studies, we searched for specific transcription factors that might regulate (affect) the expression of SGs biosynthetic genes in common centaury upon wounding. By analyzing _C.