Transmittance of Tumor-Inducing Ability to Avirulent Crown-Gall and Related Bacteria

The ielation of bacterial virulence and aviru-lence to crown-gall tumor induction under otheriwise suitalle conditions of host suseepti-bility, temperature, etc., is one of the more interesting aspects of the "erown gall " problem. There is little doubt that elucidation of this problem wAill aidl in undcerstanding the nmecha-nisms Nhereby virulent bacteria affect host cells. This paper deals with experimenits designed to deteImine whethe rvirulence, as determined by ability to induce tumor formation, ean be trans-mitte(d to nonvirulent species in the genus Agro-bacterium and other bacteriai. MATERIAL AND METHODS The organisms used in this study were: Agro-bacterium tuntefaciens, stIrain S5-6, which is highly virulent for tomato and Bryophyllutni but aviIru-lent for bean (Department of Botany, University of Chicago); A. tuniefaciens, strain NAv-1, which is an avirulent isolate (A. J. Riker, De-