Induction of Hairy Roots by Agrobacterium Rhizogenes and Growth of Hairy Roots In Vitro

The bacterial genus Agrobucterium includes two species of considerable interest to plant physiologists and pathologists alike. Infection by virulent strains of A. tumefaciens induces the formation of tumors and infection by A. rhizogenes the proliferation of roots in a wide range of dicotyledenous plants: crown-gall and hairy root diseases are not naturally recorded in monocotyledenous plants (1 ). Invasion of plant tissues by these free-living soil bacteria usually occurs at a wound site—possibly caused by insect or mechanical damage; nonvirulent strains of the bacteria may invade the plant, but only virulent strains give rise to symptoms of disease.