Biocontrol effects of endophytic and rhizospheric bacteria against the root pathogen Fusarium oxysporum of hot pepper (Capsicum annum L.)

Abstract

Plant disease needs to be controlled to keep the quality ofproducts and the abundance of food produced by farmersall over the world. Hot pepper production in Ethiopia hasbeen reduced from time to time. This is mainly due to theoutbreak of different diseases especially fusarium wilt inthe hot pepper growing areas. The objective of this studywas to isolate and characterize Plant Growth PromotingBacteria from the hot pepper rhizosphere and internal tissueswith potential biocontrol activity against Fusariumoxysporum. Thirty healthy and vigorous hot pepper plantswith intact roots and soil from the rhizospheric region werecollected randomly from hot pepper growing areas of YimaliKebele. A total of 23 endophytic and rhizospheric bacteriawere isolated from the hot pepper root and rhizosphericsoil. The combined endophytic and rhizospheric bacteriashowed a significant effect on the growth of F. oxysporumthan single isolates (P d”0.05). The bacteria isolated fromMarkofana hot pepper varieties of black clay soil showed abetter antagonistic effect on F. oxysporum than bacteriaisolated from local hot pepper varieties of reddish sandysoil. A significant percentage of inhibition between combinedendophytic and rhizospheric bacteria [endophytic (GE) +rhizospheric (GR) isolates] compared to GE+GE and GR+GR(P =0.002) was obtained. Antagonistic bacterial isolates wereable to produce different hydrolytic enzymes such aschitinase, protease, and cellulase. Bacillus species showedbetter antagonistic performance and decreased radial growthof F. oxysporum than Pseudomonas species.