Evaluation of Streptomyces spp. against Fusarium oxysporum f. sp. ciceris for the management of chickpea wilt

Abstract

AbstractIn this study, about 112 isolates ofStreptomyceswere isolated from chickpea rhizospheric soils. Among the isolated strains, five showed strong inhibitory effects against chickpea Fusarium wilt caused byFusarium oxysporumf. sp.ciceris in vitrousing plate assay and selected for further studies. The selected strains were identified asStreptomycesspp. based on morphological and biochemical characterization as well as 16S rDNA sequences analysis. Our results assigned them to strains related to genus ofStreptomyces.In vitro, antagonistic effects ofStreptomycesstrains against the disease were evaluated through the dual-culture method, volatile and non-volatile metabolites, siderophore, protease and chitinase production. All bacterial strains inhibited mycelial growth of the pathogen ranging from 26 to 44.2% in dual culture assay. The non-volatile extract of five of theStreptomycesstrains inhibited more than 50% growth of the pathogen, whereas volatile compounds were less effective on mycelial growth inhibition (20.2 to 33.4%). The ability of the biocontrol agents to produce siderophore and protease were varied, whereas, production of chitinase was detected for all strains. Results of the greenhouse assay indicated that all biocontrol agents reduced disease severity (ranging from 38.7 to 54.8%). Accordingly, strain KS62 showed higher control efficacy (54.8%). In addition, the biomass of chickpea plants (plant height and dry weight) significantly increased in plants treated withStreptomycesstrains compared to non-bacterized control. The results of this study showed that it may be possible to manage chickpea Fusarium wilt disease effectively by usingStreptomycesspecies, as biocontrol agents. Therefore, evaluating their efficiency under field conditions is needed.