Hair Root Cultures - Hairy roots are induced by transforming plant cells with Agrobacterium rhizogenes. These roots can be grown indefinitely, and in large fermenters at growth rates comparable to that of suspension cultures. Hairy roots synthesize secondary metabolites and at levels characteristic of the roots of parent plants.

A. rhizogenes may be used to transform leaf discs, other organs or even protoplasts. The hairy roots so obtained are excised and used to initiate root cultures; hairy root cultures are easily developed in most dicot plants.