ISOLATION AND CHARACTERIZATION OF RHIZOSPHERIC BACTERIA FOR BIOCONTROL OF TOMATO BACTERIAL SPECK DISEASE AGENT PSEUDOMONAS SYRINGAE PV. TOMATO

Bacterial speck of tomato, caused by Pseudomonas syringae pv. tomato (Pst), continues to be a problem for greenhouse production in the Mediterranean region of Turkey. Effective and augmentative control methods are still in need as for the numerous bacterial plant diseases. In this study, 524 bacteria were isolated from the vicinity of root area of tomato plants from 120 different locations in Adana and Mersin provinces of Turkey. The isolates were characterized and evaluated for their biocontrol potential against Pst. Cultural characteristics were determined on the basis of appearance of colonies developed on King's B media. Isolates having pectolytic activities and causing hypersensitive reaction in tobacco plants were eliminated due to possible pathogenic characteristics. Out of isolated rhizobacteria, 325 of them were found to have nitrogen fixing capacity, 11 of them were able to solubilize phosphorus, and 4 of them induced indole acetic acid (IAA) activity. Forty eight isolates showed antagonistic effect against Pst in vitro. Only 39 isolates out of 48 had siderophore effects. Rest of the isolates had more than one characteristics. The promising isolates on the basis of above parameters are planned to test in field and greenhouse conditions for the ability to reduce the impact of bacterial speck disease and to remediate the polluted soils such as saline and heavy metal contaminated soils.