Agrobacterium rhizogenes - Mediated Transformation of Medicinal Plants from the Family Rhamnaceae

A number of plants can be successfully transformed by Agrobacterium rhizogenes through the transfer of T-DNA from agrobacteria to the plant genome. Transgenic tissue – hairy roots – is produced as a result of the transformation process. This organized, genetically stable, hormone-independent transformed tissue is capable of accomplishing complex metabolic pathways, including biosynthesis and accumulation of various secondary metabolites. Somaclonal variation is often observed among the hairy root cultures. The highlyproductive hairy root lines, containing a large amount of important metabolites can be selected and grown in vitro on hormone-free media for a long period of time, whilst preserving their biosynthetic capacities. Consequently, during the last decade, hairy root cultures have been recognized as an excellent system for in vitro generation of a large biomass of transgenic tissue that could be utilized for the extraction of desired metabolites or even in the development of new compounds through novel metabolic pathways. Species from the family Rhamnaceae are well known for their capacity to synthesize the aromatic carbohydrates, anthraquinones (AQs). These metabolites with laxative action are traditionally extracted from the bark of Frangulae cortex. Applying a genetic engineering approach, the hairy root cultures of Rhamnus fallax open a convenient alternative for the production of increased amount of medically important metabolites such as AQs while protecting natural recourses and environment. _____________________________________________________________________________________________________________