Antifungal activity of Pseudomonas oryzihabitans a bacterium symbiotically associated with Steinernema abbasi towards Fusarium oxysporum and Rhizoctonia solani

Abstract

Pseudomonas oryzihabitans (=Flavimonas oryzihabitans), a symbiont of the entomopathogenic nematode Steinernema abbasi significantly inhibited the mycelium growth of Fusarium oxysporum and Rhizoctonia solani in vitro. Antifungal compounds diffused from P. oryzihabitans exhibited chemotaxis toward Fusarium and Rhizoctonia mycelia in soft (0.2%) agar. Activity occurred at 15 - 28 degreesC but was strongest at the higher temperature. P. oryzihabitans cells were also tested for their root colonization and biocontrol abilities. A polyclonal antibody confirmed the bacterium had colonized roots. P. oryzihabitans induced soil suppressiveness against Fusarium oxysporum.