## Introduction
### Chemical constituents
#### Pharmacological activities of withanolides
Opines are synthesized by plant transformed cells and are only used by _Agrobacterium_ as a source of nitrogen and carbon. Due to the similarities between the _A. rhizogenes_ and _A. tumefaciens_ infection processes, and because both microorganisms are very closely related, it has been suggested that the most important _A. rhizogenes_ oncogenes encode proteins involved in the regulation of plant hormone metabolism. Transformation of _W. somifera_ with wild type nopaline and octopine strains of _A. tumefaciens_ has been reported [75]. The oncogenic strains showed different levels of virulence in the two genotypes studied, the main difference being found in the nature of the galls formed and in their subsequent morphological competence. Ten percent of the galls obtained after infection with nopaline strain N2:73 spontaneously developed shooty teratomas of altered phenotype. The shooty teratomas grew in unsupplemented basal medium and were able to synthesize both major withanolides of the parent plants. Withanolide synthesis in shooty teratomas was much higher (0.07-0.1% withaferin A and 0.085-0.025% withanolide D) than in non-transformed shoot cultures. _Aux_ genes provide transformed cells with an additional source of auxin [85,86], but they do not seem essential for developing hairy root disease [79]. However, _rol_ genes have functions that are most likely other than that of producing mere alterations in plant hormone concentrations [87]. Several authors have investigated the effect of TR and TL regions of _A. rhizogenes_ on the growth and morphology of transformed roots and plants, but until now there have been few studies on the direct effects of oncogenes on secondary metabolism. As previously reported, a correlation exists between the expression of the _rol_C gene and the production of tropane alkaloids [88-90], _Catharanthus roseus_ alkaloids [91], and ginensosides [92]. No correlation between _rol_A and _rol_B expression and secondary metabolism was found in any of these studies. [PERSON] _et al_. [93] showed that the inoculation of leaf sections of tobacco, _Duboisia_ hybrid and _Datura_ metel plants with the A4 strain of _A. rhizogenes_ induced transformed roots with the capacity to produce putrescine-derived alkaloids such as nicotine,hyoscyamine and scopolamine. The obtained hairy roots generally presented two morphologies: typical hairy roots with a high alkaloid-producing capacity, and callus-like roots with faster growth and lower alkaloid production. The _aux1_ gene of _A. rhizogenes_ located in the TR-DNA of _A. rhizogenes_ was detected in all roots showing callus-like morphology, but only in 25-60% of the established root cultures showing typical hairy morphology. These results demonstrate a significant role of _aux_ genes in the morphology of transformed roots and the importance of typical hairy root morphology in the production of scopolamine. The studies with _Panax ginseng_ hairy roots also support the effects of the genes located in the TR-DNA on root morphology and secondary metabolism [94]. [PERSON] _et al._[25] have reported the presence of TR-DNA in all the transformed callus lines of _W. somnifera_ obtained after infection with _A. rhizogenes_ A4, thus confirming the effects of _aux_ genes on root line phenotypes. Recently, [PERSON] _et al._[95] showed that the inoculation of leaf sections of _W. coagulans_ with _A. tumefaciens_ strain C58C1 (pRiA4) induced transformed roots with two morphologies: callus-like roots (CR) with a high capacity to produce withanolides and typical hairy roots (HR) with faster growth capacity and lower withanolide accumulation. The presence of the _aux1_ gene has been confirmed in 100% of the root lines displaying callus-like morphology, but in only 12.5% of roots with typical hairy root morphology. Withanolide composition and _in vitro_ culture of an Italian chemotype of _W. somnifera_ have been reported [96]. Withanolide production by _in vitro_ cultures (callus, shoots, leaves and roots transformed by _A.