# Molecular Genetic Research and Genetic Engineering of _Taraxaxacum kok-saghyz_ [PERSON]
## 6 Genetic Transformation of TKS  
Since TKS is both a model object in the study of rubber biosynthesis and potentially valuable for agro-industrial production, it is of great interest to develop methods for the genetic transformation of this plant. One of the publications in this field was the study of [PERSON] et al. [38], who reported on the successful testing of a method for transforming TKS root explants using _A. rhizogenes_ strain _K599_ carrying a binary vector with genes for kanamycin resistance and green fluorescent protein. A hormone-free nutrient medium was used when transgenic plants of TKS and its relative TB were obtained. The average transformation efficiency (number of transgenic plants/number of root explants) was 24.7% and 15.7% for TKS and TB, respectively. A number of studies were devoted to testing RNA interference technologies in transgenic TKS plants to research the functions of rubber biosynthesis genes. Changes in the expression levels of _SRPP_ genes in transgenic TKS induced by RNAi technology demonstrated qualitative and quantitative changes in the course of rubber biosynthesis in these plants [47]. RNAi technology was also used to study the role of _cis_-ppenyltransferase by changing the expression levels of three different genes from the prenyltransferase family in the transgenic TB [52]. The silencing of polyphenol oxidase genes in transgenic TKS and _T. officinal_ was previously studied using the same RNA interference technology [79]. In recent years, the CRISPR/Cas genome editing method has been increasingly used to block the expression of the studied genes instead of using RNAi technology. As mentioned above, the TKS genome was edited by delivering CRISPR/Cas components using _A. rhizogenes_ as part of a binary vector for the knockout of the _FFT_ gene [39]. Another study was devoted to the knockout of the _TkRALFL1-like1_ gene by the CRISPR/Cas method [74]. In order to study the possibility of the biotechnological production of NR, we have developed methods for inducing hairy roots not only in TKS but also in _T. hybermann_[80, 81]. In these studies, we used different types of explants, which were infected with _A. rhizogenes_ strains A4 and 15834 under various inoculation conditions. The highest efficiency of transformation by both strains was observed when picked with a needle containing a suspension of agrobacteria into the hypocotyls. It was shown that the A4 strain was more effective in the transformation of TKS than 15834 [80]. Shoot regeneration was constantly observed from hairy roots (Figure 4), which proved the possibility of creating transgenic TKS using _A. rhizogenes_. These studies were continued and hairy roots were obtained, accumulating an average of 7.5% rubber per dry weight, which is comparable to the roots of TKS grown in the field [82]. These data may indicate the possibility of using TKS hairy roots for rubber production in the future. However, to date, this technology seems to be economically unprofitable. As for the transformation of _A. tumefaciens_, only a few works in this field are known for TKS. For example, transgenic TKS plants were created by transforming leaf discs with strain EHA105, where 6-benzylaminopurine and indoleacetic acid were used for plant regeneration [47]. CRISPR/Cas TKS mutants for the _TkALFL1-like1_ gene were also created using _A. tumefaciens_[74]. Genetic transformation of dandelions appeared to be more efficient with _A. rhizosphere_ than with _A. tumefaciens_[83]. However, it should be borne in mind that, during the transformation of _A. rhizogenes_ into plants, in addition to the target genes, _rol_-genes are also transferred, and in the future, it will become necessary to select plants without these genes. Therefore, in the laboratory of [PERSON], studies were carried out to identify the phenotypic manifestations of _rol_-genes in TKS in order to further successfully select plants according to their phenotype that do not contain or do not express these transgenes [83].