Characterization and molecular cloning in Escherichia coli of a plasmid from the mollicute Spiroplasma citri

Two plasmids, pMH1 with 7 kilobase pairs and pM41 with 8 kilobase pairs, were purified from the plant pathogen Spiroplasma citri and characterized by restriction mapping. Upon in vitro DNA recombination with plasmid pBR328 as a vector, we have cloned pMH1 in Escherichia coli. A radioactive probe obtained upon nick translation of the recombinant plasmid was used to further characterize and compare pMH1 and pM41.