## 4 Discussion
### Transcription Factors Played an Important Role in Rosemary Suspension Cells Responding to MeJA  
TFs played a key role in plant growth, development, secondary metabolism and resistance to stress [82]. In _Salvia milliorthiza_, _PAP1_ could induce the expression of _PAL_, _C4H_ and _CHS_ to promote the accumulation of anthocyanins [83], _MYB39_ and _MYB4_ could negatively regulate the synthesis of rosmarinic acid [84; 85], _ERF115_ had different regulatory effects on salvianic acid and tanshinone in different tissues and organs [86]. _MYC2_ mediated plant responding to stress, regulated the genes in the biosynthesis of many secondary metabolites [87]. AP2/ERF, bHLH, MYB, NAC, WRKY and bZIP TFs families were related to the metabolism of terpenoids, MYB and bHLH could induce plant anthocyanin accumulation [88; 89]. In _Arabidopsis_, several R2R3-MYB were involved in the regulation of flavonoid biosynthesis [90; 91; 92], _MYB4_ negative controlled sinapate ester biosynthesis through down-regulated _C4H_ in a UV-dependent manner [93], _MYB11, -12, -111_ regulated flavonoid biosynthesis by up-regulated _CHS_, _CHI_, _F3H_, _F3H_ and _FLS_[90; 94], _MYB75, -90, -113, -114_ controlled anthocyanin biosynthesis in vegetative [95], _MYB123_ controlled the biosynthesis of proanthocyanidins in the seed coat [96]. _MYB5, -14_ played a key role in seed coat polymer biosynthesis in _Medicago truncatula_[97]. _OsWRKY13_ was an important TF to resist the infection of rice blast fungus by directly or indirectly regulating the genes of SA and JA signaling pathway [98]. Over-expression _li049_, the expressions of genes related to lignin biosynthesis were significantly up-regulated and the content was increased in _Isatis indigotica_ hairy root [99]. _TcDRREB_ regulated the key gene of the paclitaxel synthesis pathway to increase the content of paclitaxel increased with JA treatment in _Taxus_ suspension cells [100]. DELLA could interact with JAZ1, reduce the inhibition of _JAZ1_ to _MYC2_ in _Arabidopsis_[101]. _RIM1_ was a negative regulator for JA signaling in _Rice_[102]. In our study, the classification of them showed that MYB was most related to MeJA. R2R3-MYB were differentially expressed under MeJA treatment, _MYB111_ was significantly up-regulated under 50 and 100 uM MeJA, and down-regulated under 10 uM MeJA. Therefore, MeJA might play a regulatory role in the synthesis of rosmarinic acid, terpenoids, flavonoids and other metabolites by including the MYB, AP2-EREBP, _MYC2_ and _DELLA_ in roseamy suspension cells. In conclusion, MeJA increased the activities of PAL, SOD, POD, CAT and PPO, and reduced the contents of H2O2 and MDA, thus accelerated the ROS scavenging. A comparative analysis of global gene expression patterns provided subsets of DEGs in roseamy suspension cells under MeJA treatment. Our study revealed the expression profiles of genes involved in plant hormones signaling pathway, flavonoids, terpenoid backbone and phenylpropanol biosynthesis pathway, TFs, indicating their regulatory role in the synthesis of the active compounds in roseamy suspension cells under MeJA treatment. We suggested a feasible working model based on the result (Figure 9). These transcriptomic data provided new insights into future functional studies, as a means of studying the molecular mechanisms on the biosynthesis of active compounds and the mining of key enzyme genes in roseamy suspension cells.