Rhizoctonia solani Kuhn is one of the soilborne pathogenic fungi have been associated with damping-off. Protection of cucumber against this pathogen is important to maximize the crop field, plant growth-promoting rhizobacteria (PGPR) have been used to suppress the growth of this pathogen as well as enhance growth of several crops. In the present study, the endophytic bacterium Paenibacillus polymyxa strain NBF188 was evaluated as a biological control agent for cucumber Rhizoctonia rot. P. polymyxa strain NBF188 showed high inhibition activity in dual culture and inhibitory halos were observed Optical microscope study revealed deformation of hyphal and enlargement of cytoplasmic vacuoles. Furthermore, the strain NBF188 showed a broad antifungal spectrum on mycelium growth of numerous important plant pathogenic fungi. In the greenhouse, seed-soaking with NBF188 (108 CFU·ml-1 ) exhibited a better biological control effect on cucumber Rhizoctonia rot and plant growth promoting ability. The control effect was 76.67% and the plant height, root length and fresh weight have increased 53.48%, 49.84% and 37.57% respectively compared with the untreated control. Experiments reported here indicate that P. polymyxa NBF188 could be a promising agent in biocontrol cucumber Rhizoctonia rot.
Paenibacillus polymyxa, Biocontrol, Rhizoctonia rot, cucumber
© The Author(s) 2014. Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License which permits unrestricted use, sharing, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.