ISOLATION OF AZOSPIRILLUM-LIPOFERUM 4T TN5 MUTANTS AFFECTED IN MELANIZATION AND LACCASE ACTIVITY

Azospirillum lipoferum 4T has original properties such as nonmotility, melanin synthesis, and laccase activity. Following random Tn5 mutagen esis in A. lipoferum 4T, we obtained 10 mutants which were affected in melanization and laccase activity. The class 1 mutants, with intermed iate levels of laccase activity, showed some coloration; the class 2 m utants, which were completely negative for laccase activity, were also colorless. The Tn5 localization on the chromosome or on the cryptic 3 00-MDa plasmid of A. lipoferum 4T was proven by hybridization for all class 1 mutants or for most class 2 mutants, respectively.