Transfer of the drug-resistance transposon Tn5 to Rhizobium

TRANSPOSONS are discrete sequences of DNA that are incapable of self-replication and can insert into DNA replicons, such as chromosomes or plasmids, in the absence of the recA gene function 1 . Insertion can be random and where it occurs into the continuity of a gene leads to non-leaky polar mutations 1 . Some transposons carry drug resistance genes and thus insertions can be mapped as drug-resistance markers 1 . We report here that Tn 5 , a transposon coding for kanamycin resistance 2 , can insert into the chromosome of Rhizobium leguminosarum , the bacterium responsible for nodulation and nitrogen fixation in Pisum , Vicia , Lathyrus and Lens .