CHARACTERIZATION OF RHIZOBIA ISOLATED FROM CAROB TREE (CERATONIA-SILIQUA)

Bacteria were isolated from root nodules of Carob tree (Ceratonia sili qua). We studied their cultural, physiological and biochemical charact eristics. Strains show-ed some variability concerning tolerance to NaC l and KCl, and none grew at pHs below 7. The mean temperature for grow th was 30 degrees C and some strains could grow at 40 degrees C. These isolates could use a great variety of carbohydrates as a sole carbon source (hexoses, pentoses, disaccharides, trisaccharides, polysacchari des and organic acids). According to their cultural and physiological features and their in vitro infectivity on their original host, we sug gest that these isolates may belong to the genus Rhizobium. Moreover, with regard to their average generation time, carbohydrate utilization , antibiotic resistance and other biochemical properties, they may be related to fast-growing rhizobia until further characterization.