Effects Of Rhizosphere Flora Transplantation From Solanaceae Rootstock On Tomato Bacterial Wilt Control And Rhizosphere Microbiome

Continuous cropping obstacles have severely restricted the growth of cash crops.Accumulation of harmful microorganisms in soil is one of the causes of continuous cropping obstacles.Moreover,effects of using biocontrol bacteria alone or in simple combinations in the field is unstable and cannot be widely promoted.Therefore,it is imperative to find an efficient and environmentally friendly method to prevent and control soil-borne diseases.In this study,disease resistance of different Solanaceae rootstocks on bacterial wilt was identified.Rhizosphere flora of two rootstocks with different disease resistance ability was transplanted into the rhizosphere of recipient plants(tomato)to determine their biocontrol effect and differences of rhizosphere micro flora.In order to determine core flora contributing to biocontrol,we analyzed changes of microbial flora in the rhizosphere of tomato before and after flora transplantation with 16S rRNA amplicon sequencing analysis.Results obtained in this study are as follows:1.Restuls showed that there was significant difference in the resistance of two wild Solanaceae crops.L.solani.ZM19 is disease-resistant and ZM2 is susceptible.The number of Ralstonia pathogens in the ZM2 rhizosphere was significantly higher than that of ZM19.The number of Ralstonia pathogens detected in the stem of ZM2 was about 2.61 × 108 CFU/g stem tissue,but no pathogen was detected in the stem of ZM19.Physical and chemical properties of rhizosphere soil were detected.pH values of ZM2 and ZM19 had no significantly difference,but it showed significant differences in soil conductivity,available phosphorus content and available potassium content.After transplanting rhizosphere flora from ZM19,disease incidence and pathogen abundance of the recipient tomato Micro-Tom were significantly reduced.2.Based on 16S rRNA amplicon analysis,it showed that β diversity,not a diversity of the rhizosphere bacterial communities from two Solanaceae rootstock showed significant difference.LEfSe analysis showed that 15 kinds of microorganisms were significantly enriched in the resistant species at different taxonomy levels,and 7 kinds of microorganisms were significantly enriched in the susceptible species.There were 2399 core OTUs related to disease resistance.The resistant-related microbial communities of resistant rootstock were mainly distributed in 11 phylums.The most abundant phylums were Proteobacteria(28%)and Gemmatimonadetes.(13%).3.Microbial community structure of recipient tomatoes significantly changed after transplantation of ZM2 and ZM19 flora to the rhizosphere.Changes of microbial community structure in recipient tomato from ZM19 was greater than that from ZM2.LEfSe analysis showed that the rhizosphere flora structure of the ZM2R and ZM19R flora was significantly different at order,family and genus levels.A total of 8 kinds of microorganisms were significantly enriched in the ZM19R flora,and 22 kinds of microorganisms were significantly enriched in the ZM2R flora.4.In the rhizosphere microflora transplantation experiment,there were 303 disease-related OTUs from ZM19,which were significantly correlated with the number of rhizosphere pathogens and disease incidence.They mainly distributed in 10 phylums,including Proteobacteria(27%),Firmicutes(11%),Patescibacteria(11%),Gemmatimonadetes(10%),Bacteroidetes(8%),Chloroflexi(7%),Actinobacteria(5%),Cyanobacteria(4%),Planctomycetes(4%),Acidobacteria(4%).OTUs shared by disease-resistance related and the bacterial group successfully transplanted was mainly distributed in 8 phylums,including Proteobacteria(26%)and(Firmicutes)thick-walled bacteria.(17%),Gemmatimonadetes(12%),Chloroflexi(8%),Patescibacteria(7%),Bacteroidetes(6%),Actinomycetes Actinobacteria(4%)and Acidobacteria(4%).The core flora remained generally stable.There were 38 microbial driving factors in the rhizosphere flora before the colony transplantation,and the microbial driving factor associated with Ralstonia solanacearum before and after the microbial flora transplantation was Acidobacteriales_norank.In summary,transplanting flora from disease-resistance Solanaceae rootstock rhizosphere to susceptible tomato Micro-Tom can effectively reduce abundance of Ralstonia pathogens and disease incidence,which have positive effects on controlling tomato bacterial wilt.By comparing the relevant flora of disease-resistance and transplatation,I found that most of the rhizosphere disease-resistant flora of the disease-resistant Solanaceae rootstocks could successfully colonize in the rhizosphere of the recipient tomato plants after transplantation.The community structure remained stable and reshaped the rhizosphere microflora of the recipient plant.The research results provide a theoretical basis for controlling tomato soil-borne diseases with core flora.