Inhibitory activity of Paenibacillus macerans and Paenibacillus polymyxa against Ralstonia solanacearum

The inhibitory activities of seven Paenibacillus polymyxa strains and ninePaenibacillus macerans strains against Ralstonia solanacearum strains were examined. Result from this study indicated that the growth of all R. solanacearumstrains except strain E406 were inhibited by P. macerans MB02-992 and P. polymyxa MB02-1007, while the other fourteen Paenibacillus strains had no in vitroinhibitory effect against R. solanacearum strains. In addition, suspensions of the two antagonistic bacteria showed antibacterial activities against R. solanacearum under different treatments and reduced the disease incidence and severity of tomato bacterial wilt. Overall, this study clearly demonstrates that antagonistic substances may play an important role in biocontrol of the two antagonistic bacteria. However, antimicrobial activities of P. macerans and P. polymyxa depend on the Paenibacillusstrains and the target pathogen. This is the first report about the antibacterial activities of Paenibacillus strains against R. solanacearum strains isolated from different host plants.   Key words: Paenibacillus, antagonistism, biovar, Ralstonia solanacearum, tomato wilt.