## 4 Plant Tissue and Organ Cultures in Bioreactors
### Temporary Immersion System
showed that _Senua obtusifolia_ transgenic hairy roots with an over-expression of the _PgSS1_ gene from _Panax ginseng_ contain a higher level of betulinic acid, a triterpen saponin, than roots without the construct [113]. Betulinic acid has various biological properties, including antioxidant, anti-inflammatory, and anti-cancer. The data indicate that their anti-tumour effects are triggered by the induction of apoptosis via the mitochondrial pathways in cancer cells [114]. [PERSON] et al. revealed that the overexpression of the ginseng's biosynthetic pathway key gene _PgSSQSI_, which can upregulate the expression of squalene epoxidase, \(\beta\)-amyrin synthase, and cycloartenol synthase, resulted in a twofold increase of phytosterols and a 1.6- to 3-fold increase of total ginseng, a group of glycosylated triterpenes, in transgenic ginseng adventitious root cultures [115]. Ginsenosides also act as antioxidation and anti-inflammatory factors and have beneficial effects on cardiac and vascular diseases [116]. In turn, [PERSON] et al. noted that the expression of the tomato regulatory gene _SIMYB75_, an MYB-type transcription factor, promotes anthocyanin accumulation in tomato fruits [117]. Overproducing of anthocyanins can be an effective way to extend a tomato's shelf life [118]. Elsewhere, [PERSON] et al. showed a significant increase in the production of phenolic acids, including neochlorogenic acid, chlorogenic acid, caffeic acid, \(p\)-coumaric acid, and ferulic acid, in the transgenic roots of _Leonurus sibiricus_ through the overexpression of the AtPAP1 transcriptional factor [119]. Plant-derived phenolic acids are considered to be natural antioxidants with potential health benefits [120]. [PERSON] et al. showed that overexpression of the octadecanoid responsive _Catharanthus AP2_-domain protein (ORCA3) and strictosidine glucosidase in the hairy roots of _Catharanthus roseus_ increased the production of terpenoid indole alkaloids by 47%, including serpentine, ajmalicine, catharanthine, tabersonine, lochnericine, and hornamericine--all of which exhibit interesting pharmaceutical activities such as anticancer, antimalarial, and antiarrhythmic functions [121]. [PERSON] et al. demonstrated that the transformed roots of _Taxus bacata_ with the overexpression of the _TXS_ gene showed 265% greater diterpene and taxane production after MeJA elicitor treatment [122]. The taxanes, paclitaxel and docetaxel, act as anticancer agents by stabilizing the microtubules during cell division [123]. Clustered regularly interspaced short palindromic repeats (CRISPRR) along with the CRISPR-associated proteins (Cas) system that was found in various bacteria serves as a defense mechanism against viruses. The potency of the technology enables the ability to target any sequence throughout a cell. Thus, this can be a genome editing system that may regulate secondary metabolism in plants [124]. The data showed that the contents of phenolic acids, including rosmarinic acid and lithospheric acid B, as well as tanshione synthesis were decreased in the knocked out rosmarinic acid synthase gene [125] and diterpene synthase gene [126] lines of _Salvia milliorrhiza_, respectively. _Arabidopsis thaliana_ and its ubiquitin-protein ligase (HOS1) mutants are characterized by changes in phytoalexins synthesis [127]. In addition, bioreactor cultures may also increase the secondary metabolite production by increasing biomass, thus creating a fairly cheap system for the production of active compounds. Of course, it should be remembered that the cultivation of cells, tissues, and plant organs in a bioreactor also has some limitations, despite the huge advances in bioprocess engineering. One of them is the time-consuming and labor-intensive procedures related to the aging, inoculation, and cleaning of the entire system before and after cultivation.