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چکیده
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Bacteria produces secondary metabolites (SMs) and volatile organic compounds (VOCs) that have a significant role in the control of phytopathogens. In this study, the antagonistic activity and the effect of VOCs produced by endophytic bacteria Bacillus sp. B186, Bacillus sp. H274, Pseudomonas sp. B451, Bacillus sp. Andi542, and Streptomyces sp. Sh800 isolated from sugar beet and sea beet plants on the virulence traits of Enterobacter roggenkampii Kh2, the causal agent of postharvest sugar beet soft rot disease were evaluated. All endophytic bacteria tested showed antagonistic activity against bacterial pathogens in vitro. The results of enzymatic activity, HCN production, antibiosis, and siderophore production were varied amongst strains. The VOCs emitted from endophytic bacteria significantly reduced soft root symptoms and the growth of E. roggenkampii Kh2 at different levels. Our results revealed that VOCs produced by all endophytic bacteria significantly reduced swarming and swimming motility, also chemotaxis behavior of E. roggenkampii Kh2 cells toward sugar beet root extract. The VOCs produced by endophytic bacteria except Bacillus sp. B186 significantly reduced twitching motility of E. roggenkampii Kh2. The influence of VOCs on biofilm formation by bacterial pathogen was varied amongst endophytic bacteria. The gas chromatography-mass spectrometry (GC-MS) analysis revealed that strains B186, B451, Andi542, H274, and Sh800 produced 14, 34, 36, 28, and 16 VOCs, respectively with high quality. Our finding provide new information regarding the potential of VOCs with antibacterial activity and as a biocontrol tool for reducing bacterial soft rot disease at harvest.
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