STRAINS OF THE GENUS SERRATIA AS BENEFICIAL RHIZOBACTERIA OF OILSEED RAPE WITH ANTIFUNGAL PROPERTIES

Isolates of Serratia have been isolated from the rhizosphere of oilsee d rape. The percentage of Serratia in this microenvironment was determ ined as 12.4% of the total antifungal bacteria. Serratia liquefaciens, S. plymuthica and S. rubidaea were found. All of the isolates showed an antifungal activity against different phytopathogenic fungi in vitr o but the efficiency of strains was different. The antifungal mechanis ms of 18 selected strains were investigated. Direct antifungal effect may be based on antibiosis (production of prodigiosin and pyrrolnitrin ) and production of lytic enzymes (chitinases and beta-1,3-glucanases) . Potent siderophores were secreted by the strains to improve the avai lability of iron. No strain was able to produce cyanide. Most of the s trains secrete the plant growth hormon indole-acetic-acid which can di rectly promote the growth of roots. The mechanisms were specific for e ach isolate.