Journal of Pure and Applied MicrobiologyVol. 8 No. Special Edition Nov. 2014

The Biocontrol Effect of Paenibacillus polymyxa Strain NBF188 on Cucumber Rhizoctonia Rot and its Growth-Promoting Effect

Daye Huang*1, Jinping Li2, Jingwu Yao1, Chunxia Cao1, Nina Yang1, Ben Rao1, Tong Long1 and Ziwen Yang1

1Hubei Biopesticide Engineering Research Center, Wuhan, China; 2Beijing Plant Protection Station, Beijing, China.

Received on 18 June 2014 and accepted on 28 July 2014

 

ABSTRACT

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.

Keywords : Paenibacillus polymyxa; Biocontrol; Rhizoctonia rot; cucumber.