[The presence of Agrobacterium tumefaciens in lucerne root nodules]

Agrobacterium tumefaciens does not penetrate into nodules on the roots of lucerne with the active strain of nodule bacterium as was established with the aid of genetic markers and plant selection. A nodule, whose shape was not typical and which did not fix nitrogen, was formed on the root of lucerne inoculated with the culture of Agrobacterium tumefaciens treated with UV. A bacterial strain isolated from the nodule was identical to A. tumefaciens according to its resistance to streptomycin and several cultural properties. Upon repeated inoculation with the isolated strain, nodules were formed in 50% cases.