Phenotypic characterization of indigenous rhizobia nodulating chickpea in Turkey reveals high diversity

A total of 120 root-nodule bacteria from chickpea plants (Cicer arietinum L.) from six regions in Turkey were characterized using 71 phenotypes. Utilization of carbon and nitrogen sources, tolerance to salt stress, temperature and pH, resistance to antibiotics and heavy metals and ability to produce some enzymes, were assessed. 90% of the isolates produced mucously, circular, smooth-margined and watery to creamy colonies with 2–4 mm diameter after 1-3 days of growth. The isolates utilized different compounds as sole carbon and nitrogen sources, endured 2% salt, grew optimally at 25-35°C and pHs between 6-8, exhibited insensitivity to the heavy metals Zn, Hg, and Cu and the antibiotics kanamycin, streptomycin and tetracycline. Numerical analysis separated the isolates into three clusters at 25% similarity. Results revealed diversity among isolates and were consistent with previous findings on chickpea Mesorhizobia.