Induction of polygalacturonase production in legume roots as a consequence of extrachromosomal DNA carried by Rhizobium meliloti.

The ability of Rhizobium meliloti to induce polygalacturonase production in legume roots decreased during culture under laboratory conditions but was inducible with mitomycin C. This character was irreversibly lost after treatment with acridine orange. Extrachromosomal DNA of molecular weight 5.9 x 10(6) daltons was detectable in neutral sucrose gradient but was absent from cells 'cured' with acridine orange. Therefore, the ability to induce the enzyme production may be controlled by a plasmid.