Phenotypic Variations of Endophytic Bacteria Associated with Carob Tree (Ceratonia Siliqua L.)

We aimed to characterize 83 endophytic bacteria isolated from roots (73 isolates coded IRC) and epicotyls (11 isolates coded IEC) of young Carob (Ceratonia siliqua L.) seedlings. These seedlings were obtained from seeds collected in several regions in Morocco. 30 IRC and 4 IEC were selected on the basis of PCR-Pep for the further analyses. All the strains exhibited a wide tolerance to NaCl and 30 % tolerated well concentration up to 11 % NaCl. Strains showed also a wide tolerance to the variable pH. 60 % of strains grew well at pH4. Most of the strains were resistant to different antibiotics but were sensitive to kanamycin and tetracycline. The strains showed a resistance to heavy metals except mercury chloride that was toxic at a low concentration 50 µg.ml-1. According to their phenotypical features, the associative bacteria were very similar to eight symbiotic bacteria previously identified by Missbah in 1996 and used in this work.