Isolation and Identification of Biocontrol Bacteria from Tomato Rhizosphere and Evaluation on Biocontrol Potential against Fusarium Root Rot

Zeng Jingjin; Zhao Haoyu; Liu Jiang; Lu Qing

doi:10.14083/j.issn.1001-4942.2025.02.019

Abstract：In order to screen efficient antagonistic strains against Fusarium root rot,some strains were i-solated from the rhizosphere soil of healthy tomato,and then the taxonomic status and antagonism of the key antagonistic bacteria were identified and evaluated based on morphological,physiological and biochemical characteristics and 16S rRNA gene sequence.Their biocontrol effects were also determined by pot and field in situ cultivation experiments.The results showed that 93 strains were obtained from the rhizosphere soil of healthy tomato in the facility disease area,and 7 strains with bacteriostatic effect were obtained by using Fu-sarium oxysporum as the target bacterium.Through qualitative and quantitative detection,it was found that the strain MS06 had the strongest antagonistic effect,and had the characteristics of nutrient activation,IAA secre-tion,siderophore production,cellulose and protein degradation.Based on morphological and 16S rRNA phylo-genetic analyses,MS06 strain was identified as Bacillus velezensis.The fermentation broth of B.velezensis MS06 was applied to pot and field experiments,it was found that the incidence rate of tomato Fusarium root rot were 0 and 4.87％,the disease indexes were 0 and 1.87,and the relative control efficiency were 100.00％and 80.21％,respectively.It was speculated that its antibacterial mechanism was to made the F.oxysporum lose infection ability through dissolving cell wall and mycelium by secreting chitinase and cellulase,so as to inhibit the growth of pathogenbacteria.In summary,B.velezensis MS06 had excellent biocontrol function,and the field application of its solid agent had good control effect on tomato Fusarium root rot,which might be used as a candidate strain resource for tomato probiotic antagonistic agent.