Presence of unique repeated insertion sequences in nodulation genes ofRhizobium ‘hedysari’

✍ Scribed by F. Meneghetti; S. Alberghini; E. Tola; A. Giacomini; F. J. Ollero; A. Squartini; M. P. Nuti

• Book ID: 104616536
• Publisher: Springer
• Year: 1996
• Tongue: English
• Weight: 518 KB
• Volume: 186
• Category: Article
• ISSN: 0032-079X
• DOI: 10.1007/bf00035064

✦ Synopsis

Cloning and sequencing of DNA from a symbiotic large plasmid in Rhizobium 'hedysari' strain IS 123 required for its nodulation of the mediterranean legume crop Hedysarum coronarium (sulla) and complementation studies of nod-mutant derivatives led to the characterization of a 30-kb region containing common and host-specific nod genes. This DNA region also contained at least six copies of a novel insertion sequence-like structure, some of which appeared to have suffered deletions. This 0.8 kb novel element carries two 17-bp flanking inverted repeats and an open reading frame showing homology with a transposase from Staphylococcus aureus. Hybridization studies revealed that several strains of Rhizobium 'hedysari' carry this element in various copy number. The six copies in strain IS 123 appear clustered specifically within the pSym nod region.

The significance of this IS element in rhizobia and its possible use as a probe for taxonomic and phylogenetic studies of Rhizobiaceae is addressed.