Stability, frequency and multiplicity of transposon insertions in the pyoverdine region in the chromosomes of different fluorescent pseudomonads

Transposon mutagenesis in different fluorescent pseudomonads was studied. Pyoverdin negative (Pvd-) mutants were detected by their lack of fluorescence in iron-limited media and by their inability to grow in the presence of the iron chelator ethylenediamine di(o-hydroxyphenylacetic acid). It was shown that in P. aeruginosa, Tn5 and mini-Tn10 insertions are unstable and yield a high percentage of Pvd- mutants.