Mechanisms For The Impacts Of Agricultural Management Practices On Sorghum-Associated Microbiomes

Crop harbors diverse microbial communities,and these plant-associated microbial communities are collectively referred to as the plant microbiome.Plant microbiome plays key roles in the regulation of terrestrial ecosystem function and service,including biogeochemical nutrient cycling,climate regulation,and plant production.However,we lack empirical evidence for the systematic studies on the effects of fertilization regimes on plant microbiome,which mainly focused on the soil environment in the previous studies.Investigating responses of the entire plant microbiomes(including bacteria,fungi,and protists)diversity and network interactions to different fertilization treatments and their Influence mechanism,can provide theoretical support for regulating plant microbiome and improving agricultural production.In this study,high-throughput sequencing was employed to characterize bacterial,fungal,and protistan taxonomic composition in the sorghum leaf,root,rhizosphere soil and bulk soil which collected at maturity.Based on the fungal community,we contrasted the resulting taxonomic identities against the FUNGuild database.A series of statistical analysis methods such as random forest analysis,structure equation model,network analysis and linear discriminant analysis were used to explore effect of fertilization regimes on plant microbiome and its mechanisms.The obtained results are described as follows:1.Amplicon sequencing of 16 S rRNA gene and internal transcribed spacer(ITS)region was used to characterize bacterial and fungal community compositions,respectively.In conclusion,we provide novel evidence that the eight-year fertilization practices significantly influenced the diversity and compositions of sorghum associated microbiomes across the four compartments.Rhizosphere and bulk soils had significantly higher microbial diversity than phyllosphere and root endophytes.Microbiota in leaf phyllosphere and root endosphere are relatively more resistant,than rhizosphere and bulk soil microbiota,to fertilization treatments.Fertilization influenced plant microbiome directly or through influencing soil properties indirectly.2.In conclusion,our study provides novel insights that fertilization significantly altered the relative abundances of specific protistan consumers and parasites in sorghumassociated compartments(phyllosphere,rhizosphere soils and bulk soils).Fertilizationinduced changes in the protistan communities could be attributed to the interactions of bacterial/fungal communities and soil properties,and in turn,protists may exert top-down control on the communities of bacteria and fungi,with unknown consequences for their regulated ecosystem functions and crop performance.Our study highlights the necessity to consider protist and their interactions with other microbes in evaluating the effects of agricultural management practices on crop-associated microbiomes.Understanding the dynamics of protists and their food web interactions will provide a way forward to engineer complex crop microbiomes with predictable behaviour and robust outcomes.Future phytobiome research should account for the various components within the plant habitat,especially when insights should be applied for plant health.3.According to the FUNGuild database,we examined the effect of fertilization treatments on plant fungal pathogens in four compartments.We found that the compartments strongly affected plant fungal pathogens.And the application of organic fertilizers more strongly reduced plant fungal pathogens in rhizosphere and bulk soil than phyllosphere and root endophyte.Organic fertilizers may inhibit pathogens by affecting bacterial and protozoan communities.4.Based on the above sequencing results,we explore the relationship between plant microbiome(bacteria,fungi and protists)and plant productivity(yield and quality).According to the FUNGuild database,we further explore the relationship between pathogens and plant productivity.In my study,multiple bacterial and fungal genera were identified as important biological predictors of sorghum yield and protein content,and might be useful for harnessing the potential benefits of plant-associated microbiomes for improved nutrient acquisition and resistance to unfavorable environments.Our findings suggest that,the changes in crop-associated microbiomes due to intensive agricultural management may ultimately have consequences for crop productivity and food security.Together,this study investigates effects of different fertilization treatments on plant microbiome,and reveals the influencing mechanism.Besides,approved fertilization treatment based on regulating plant microbiome should be built in the future.It is a good view to establish a sustainable agricultural development model by increasing beneficial microorganisms that promote plant growth and nutrient absorption,and suppressing pathogenic bacteria that may cause plant diseases,and establish a sustainable agricultural development model.