CHARACTERIZATION OF RHIZOBIA NODULATING ACACIA ISOLATED FROM MOROCCAN DESERTJamal Eddine El Jamali, Loubna Temsamani, Ibtissam El Hilali, Fatiha Brhada, Imane Chaoui, Mohammed El Mzibri and Abdelkarim Filali-MaltoufAbstract Fifty seven rhizobia nodulating Acacia were isolated from the soil by trapping at laboratory with seedling of A.gummifera and A.raddiana. The target sites for soil collection were dunes of the Moroccan desert where acacia has disappeared from decades. The bacteria isolated from the collected nodules displayed a wide tolerance to salinity (44% of strains tolerated up to 1190 mM Nacl ) to acidity and alkalinity (80% of strains grew well at pH 4.5) and to extreme temperatures ranging from 4 °C to 50 °C (44% grew at temperature of 45 °C). The strains were resistant to different antibiotics but were sensitive to tetracycline. They were also highly resistant to heavy metals like Aluminium, Zinc and Manganese (400 μg/ml). The study of genetic variability of these isolates was assessed by DNA fingerprinting using REP-PCR. Patterns obtained on agarose gel were strain specific and indicated a considerable diversity. Restriction Fragment Length Polymorphism (RFLP) analysis of 16 S rRNA genes (rDNA) indicated a large diversity of strains and showed a relatedness of some isolates to Mesorhizobium huakii and to Sinorhizobium fredii for others. |