Effect Of Biocontrol Bacteria On Rhizosphere Soil Microbial Community Of Potato With Black Scurf

Potato black scurf is a destructive soil-borne disease caused by Rhizoctonia solani Kuhn,which seriously affects the yield and quality of potato.In this study,the field was used to evaluate the effect of biocontrol bacteria on the prevention and treatment of potato black scurf.On this basis,the community structure and diversity of potato rhizosphere soil microorganisms affected by biocontrol bacteria were analyzed through highthroughput sequencing technology.At the same time,its effect on soil enzyme activity in rhizosphere soil was evaluated.The main results are as follows:1.The biocontrol effect of inoculating two biocontrol bacteria W5 and Y1 on potato black scurfBoth strains W5 and Y1 could produce bacteriostatic substances such as protease,cellulase,siderophore and HCN.Further field experiments showed that inoculation with Bacillus subtilis W5 or Y1 could significantly reduce the disease index of potatoes,with the control efficiency reaching 54.51% and 44.40% respectively.This indicated that inoculation with strain W5 or Y1 could effectively control potato black scurf.2.The effect of inoculating biocontrol bacteria on the microbial structure in potato rhizosphere soilThrough high-throughput sequencing analysis,it was found that the inoculation of biocontrol bacteria increased the diversity of the bacterial and fungal communities of potato rhizosphere soil microorganisms,and at the same time affected the species composition of potato rhizosphere soil microorganisms.After inoculated with the biocontrol bacteria W5 or Y1,some pathogenic inhibition bacteria were concentrated in the rhizosphere of potato,such as Streptomyces,Nitrospira,Pseudomonas,Mesorhizobium,Bacillus,Penicillium and Trichoderma.At the same time,the relative abundance of some potential plant-pathogenic fungi causing soil to become more unhealthy was reduced,such as Zopfiella,Podospora,and Gibberella.This indicated that inoculation of biocontrol bacteria would increase the relative abundance of beneficial bacteria in the soil,while decrease the abundance of potential pathogenic fungi,which would change the microbial community structure in a beneficial direction.3.The effects of inoculation of biocontrol bacteria on carbon source metabolism of potato rhizosphere soil microorganismsAccording to the analysis of carbon source metabolism results of Biolog-ECO,t The AWCD of the healthy control group and the biocontrol group were significantly higher than those of the pathogenic control group(P < 0.05).According to the diversity index of the soil microbial communities in each group,it was found that microbial diversity in healthy control group and inoculated with biocontrol bacteria was significantly higher than that in pathogenic control group(P < 0.05).According to the principal component analysis,the biocontrol group and the control group were separated from each other,which indicated that the metabolic characteristics of the microbial communities of the biocontrol group and the control group were different.In conclusion,inoculation of biocontrol bacteria enhanced the carbon source metabolism of the soil microbial community.4.The effect of inoculation against the activity of the soil enzyme in the root of the potatoThe enzyme activity of potato rhizosphere soil in each treatment group was detected,and the results showed that the inoculation of two biocontrol bacteria could significantly enhance the enzyme activity of urease,catalase,protease and cellulase in potato rhizosphere soil(P < 0.05).