Bacterial Diversity Of Potato Rhizosphere Soil In Different Habitats And Application Effect Of Compound Microbial Agent Against Potato Common Scab

With increasing emphasis on potato production in China,the scale and professionality of its planting grow at a very fast speed in recent years.Ever-increasing application intensity of chemical fertilizers and pesticides,together with succession cropping,lead to more and more serious soil-borne diseases representing by potato common scab year by year.In some field,the incidence of disease reaches 90%,which causes huge economic loss to farmers.Soil rhizosphere samples were collected in the potato fileds with oneyear of continuous cropping and minor soil-borne disease in Xiji(Ningxia,northwest),three years of continuous cropping and serious soil-borne disease in Guyuan,(Hebei,north)and five years continuous cropping without soil-borne disease in Hailar,(Inner Mongolia,northeast),respectively.Then,high-throughput sequencing technology was employed to compare the differences in bacterial community structure from these samples,Provide a certain theoretical basis for the prevention and treatment of potato common scab.At the same time,re-screening using existing strain resources.,many strains of bacteria with high resistance to potato common scab were obtained.Two strains of antagonistic antibacterial compounds were compounded to obtain compound fungi,prevention and control experiments were conducted in three disease-prone plots in Dingxi(Gansu),Luliang(Shanxi),and Harbin(Heilongjiang),Strive to obtain a compounding method that can be used in many areas and has a wide range of prevention and control effects.Provide a feasible method for the prevention and treatment of potato common scab.The main conclusions are as follows:(1)A total of 617,558 effective bands and 3,077 sortable operating units(OTUs)were obtained from the three groups of samples.Among them,the largest number was sourced from Proteobacteria,and the proportion was above 33%.In these three groups of samples,compared with soil samples from the field without potato soil-borne disease(Guyuan County,Hebei Province),the number of bacteria,species,bacterial diversity,and species richness decreased significantly in soil samples from potato fields with severe soil-borne diseases.Meanwhile,augmentation of the numbers of pathogen bacteria and reduction of the numbers of probiotics were also found.Specifically,we found the number of Actinobacteria increased at a large scale,while that of Proteobacteria,Chloroflexi and Acidobacteria decreased dramatically.(2)We also found changes of composition and quantity of bacteria(especially Actinomycetes)were more related to total phosphorus content of soil.Bacteria with significant differences in composition and quantity(especially actinomycetes)were significantly related to soil total phosphorus content.Excessive application of chemical fertilizers and continuous cropping throughout the year changed the soil bacterial community structure and the ecological environment deteriorated,resulting in the occurrence of soil-borne diseases.(3)In the control experiment of compound fungicides,two formulas with certain application value were found.Among them,formula 6 had a control effect of 63.1%in Luliang Experimental Field(Shanxi Province),21%in Harbin Experimental Field(Heilongjiang Province),and 59.7%in Dingxi Experimental Field(Gansu Province),increase production by 33.2%.Formula 5 had a control effect of 19%in the Harbin test field(Heilongjiang Province)and 42%in the Dingxi test field(Gansu Province),the yield increase effect reached 37.3%.