Hairy root culture, also called transformed root culture, is a type of plant tissue culture that is used to study plant metabolic processes or to produce valuable secondary metabolites or recombinant proteins, often with plant genetic engineering.
[1] A naturally occurring soil bacterium Agrobacterium rhizogenes that contains root-inducing plasmids (also called Ri plasmids) can infect plant roots and cause them to produce a food source for the bacterium, opines, and to grow abnormally.
[7] The Ri plasmids can be engineered to also contain T-DNA, used for genetic transformation of the plant cells.
The resulting genetically transformed root cultures can produce high levels of secondary metabolites, comparable or even higher than those of intact plants.
[8] Hairy root culture can also be used for regeneration of whole plants and for production of artificial seeds.