| Tomato wilt disease is an important bacterial disease in the field.The causal agent is living in and transmitted through soil,thus causes a great concern on the prevention and control of wilt disease.In the previous research in this lab,we isolated a Pseudomonas putida A1 train,which has antibacterial activity on the pathogen of tomato bacterial wilt.For further effectively usage of P.putida A1,this paper intends to explore the reasonable strategies to enhance the control efficacy on tomato and blight,and explore the molecular mechanism used by A1 strain required for antibacterial activity:(1)In irrigation inoculation experiment,the application of cell suspension of P.putida A1 of 5 mL OD600=0.6 showed the most high control efficacy on tomato bacterial wilt.The disease index reduced 37%at 7 days post inoculation.Application of high concentration of cell suspension resulted in a decreased control efficacy.(2)Biocontrol agents P.putida A1 and Bacillus subtilis K1 did not show any antimicrobial activity each other,and thus were mixed together to enhance the control efficacy on tomato bacterial wilt.The mixing ratio of 2:1 was the best usage for controlling.The disease symptom was delayed for 4 days,and the disease index was the lowest in each observation time point.At 11 days post inoculation,the disease indexs of the other treatments were reached to 100%,while the disease index of 2:1 mixing ratio was only 78%.(3)Although the application of Al did not have a significant effect on growth of 5-leaf old plants,the germination rate of seeds was affected by using high concentration of Al cells.(4)In order to gain a better understanding of the possible antimicrobial substance produced by P.putida A1,about 400 mutants were constructed by using Tn5 randomly insertion.The insertion in a MATE(multidrug and toxic compound extrusion)gene resulted in the loss of antibacterial activity.The complementation and prokaryotic expression analysis indicated that MATE had antimicrobial activity. |
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