Identification of Azospirillum strains by restriction fragment length polymorphism of the 16S rDNA and of the histidine operon.

DNA fingerprints of several Azospirillum strains, belonging to the five known species A. amazonense, A. brasilense, A. halopraeferens, A. irakense and A. lipoferum, were obtained by restriction analysis of the amplified 16S rDNA and by restriction fragment length polymorphism of the histidine biosynthetic genes. Data obtained showed that amplified rDNA restriction analysis is an easy, fast, reproducible and reliable tool for identification of Azospirillum strains, mainly at the species level, whereas restriction fragment length polymorphism could, in some cases, differentiate strains belonging to the same species. Moreover, both analyses gave congruent results in grouping strains and in the assignment of new strains to a given species.