Induction and growth of hairy roots for the production of medicinal compounds

The development of genetically transformed plant tissue cultures and mainly of roots transformed by Agrobacterium rhizogenes (hairy roots), is a key step in the use of in vitro cultures for the production of secondary metabolites. Hairy roots are able to grow fast without phytohormones, and to produce the metabolites of the mother plant. The conditions of transformation (nature and age of the explants, bacterial strain, bacterial density, and the protocol of infection) deeply influence the frequency of the transformation events as well as the growth and productivity of the hairy roots. Then optimization of the culture parameters (medium constituents, elicitation by biotic or abiotic stress) may enhance the capability of the hairy roots to grow fast and to produce valuable compounds.