Diversity of Partial 16S rRNA Sequences Among and Within Strains of African Rhizobia Isolated from Acacia and Prosopis

Sinorhizobium arboris sp. nov. and Sinorhizobium kostiense sp. nov., isolated from leguminous trees in Sudan and Kenya

“…They grouped with the Senegalese S. saheli strains by dot-blot hybridization, rep-PCR and protein analysis. By 16s rDNA analyses they were slightly different from the type strain but very close to it (Haukka et al, 1996;Nick, 1998;Nick et al, 1999). In DNA-DNA reassociation analysis, strain HAMBI 1496 was a typical S. saheli strain (Nick et al, 1999).…”

“…De Lajudie et al (1994) have shown that tropical, fastgrowing rhizobia isolated in West Africa are very diverse but are clearly different from previously established species. Sudanese and Kenyan tree nodule isolates showed wide diversity by numerical taxonomy (Zhang et al, 1991) and this was later confirmed by several genotypic analyses (Haukka & Lindstrom, 1994;Haukka et al, 1996;Nick, 1998;Nick et al, 1999). The previous studies led us to complete the polyphasic taxonomy of the Sudanese and Kenyan strains by using SDS-PAGE of total bacterial proteins, multilocus enzyme electrophoresis (MLEE) and total 16s rRNA sequence analysis.…”

“…These rhizobia were first found to be very diverse by numerical taxonomy (Zhang et al, 1991) and were further studied by molecular biological methods including pulsed-field gel electrophoresis (Haukka & Lindstrom, 1994), 16s rDNA analyses (Haukka et al, 1996;Nick, 1998) The 16s rRNA and cellular fatty acid analyses showed that almost all the Sudanese and Kenyan isolates belong to the genus Sinorhizobium (Haukka et al, 1996;Nick, 1998; S. W. Tighe & B. D. W. Jarvis, unpublished results). Numerical taxonomy had grouped the majority of these strains in two main clusters, which were phenotypically separate from established species (Zhang et al, 1991), and this finding was confirmed by several genomic analyses (Haukka & Lindstrom, 1994;Haukka et al, 1996;Nick, 1998;Nick et al, 1999). To complete the classification of the sinorhizobial isolates, 30 strains were further compared with established rhizobial species by SDS-PAGE of total proteins, 20 strains were studied by MLEE and the full length sequences of the 16s rRNA genes from two strains representing the two main clusters were determined.…”

Mesorhizobium chacoense sp. nov., a novel species that nodulates Prosopis alba in the Chaco Arido region (Argentina).

“…Species of the genus Prosopis are important trees in many ecosystems throughout South America and some have been introduced into Africa, where they can be nodulated by indigenous rhizobia (de Lajudie et al, 1998a ; E. Vela! zquez and others Haukka et al, 1996 ;McInroy et al, 1999). Apart from the above references, little work has been described concerning the taxonomy of American rhizobial symbionts of Prosopis.…”

The Symbiotic Efficiency of Legume Tree Rhizobia for Host Range Legumes in Central Saudi Arabia

“…Similar results were reported by Mahmood and Akthar (2008) when Vigna mungo was successfully cross-inoculated with the Rhizobium isolates from tree legumes. The Rhizobium isolates species that failed to nodulate in those acacias might be explained by the loss of a symbiotic plasmid (sym plasmid) or a lateral gene transfer or changes in the host specific nod gene (Haukka et al, 1996;Kucuk et al, 2006;Han et al, 2008). Environmental conditions, especially water deficiency, may play a crucial role in nodulation and may be responsible for some non-specific nodulation (Ben Ramdhane et al, 2009;Fitouri et al, 2012).…”