Screening of biofilm forming rhizobacteria of field crops for biological control of Pectobacterium carotovorum subsp. carotovorum

In this research for obtaining rhizobacteria with high ability of biofilm formation and investigation of their role in biocontrol of Pectobacterium carotovorum subsp. carotovorum, first 100 samples from East and West Azarbaijan provinces were collected and 214 bacterial isolates were isolated and purified by serial dilution method. Obtained isolates were screened based on their inhibition against Pectobacterium and the ability of biofilm formation under in vitro. Out of 214 isolates, 13 isolates showed high antagonistic activity against Pectobacterium under in vitro condition and 12 isolates showed high ability of biofilm formation. In potato slices bioassay, isolates with high ability of biofilm formation such as G19-1 and G177 inhibited the establishment of pathogen and they prevent soft rotting. However, in greenhouse studies only isolate G177 controlled the disease and in addition, it increased the stem growth as well. In general, obtained results from this study showed that biofilm formation as a mechanism solely is not responsible for biocontrol of Pectobacterium and this factor is effected by different agents.