Effect Of Interaction Between AM Fungi And Rhizobia On Medicago Sativa Rhizosphere Microbial Diversity

This article take Medicago sativa L.as the research object.By comparing the physicochemical properties of soil rhizosphere and non-rhizosphere soil,soil microbial diversity and community structure composition of Alfalfa soil at different periods in the blank group and 6 different inoculation treatment groups,the microorganisms were analyzed.The relationship between community structure and physical and chemical properties,and the effects of inoculation with AM fungi and rhizobium on soil microorganisms in Alfalfa were discussed.At the same time,Tax4 Fun and FUNGuild software were used to predict the soil microbial function,and the effects of inoculation with AM fungi and rhizobium on the soil microbial function of Alfalfa were investigated.The main conclusions are as follows:(1)The study found that compared with non-inoculation,the total nitrogen and total phosphorus contents of the single inoculation of Glomus intragranularis(GIR),the single inoculation of Glomus mossii(GMR),the single inoculation of Rhizobium(KR),the double inoculation of Glomus mobilis and the Rhizobium(GMKR)treatment groups were significantly reduced,the alkaline hydrolysis nitrogen contents of the single inoculation of Rhizobium(KR)and the double inoculation of Glomus mobilis and the Rhizobium(GMKR)treatment groups were significantly increased,and the available phosphorus was increased in the single inoculation of Glomus intragranularis(GIR),the single inoculation of Glomus mossii(GMR),and the double inoculation of Glomus mobilis and the Rhizobium(GMKR)treatment groups.The content was significantly reduced,indicating that inoculation with AM fungi and rhizobium effectively promoted the alfalfa nitrogen and phosphorus cycle,promoted the absorption of nitrogen and phosphorus nutrients,and the double-inoculation group with Glomus and Rhizobium treatment group was higher than the single-inoculation treatment group.(2)A total of 3,849 OTUs were obtained by high-throughput sequencing of bacterial16 Sr RNA,which belonged to 398 species,595 genera,59 orders,132 orders,249 families,and 595 genera.The main dominant bacteria are Proteobacteria(52.81%-81.46%),Bacteroidetes(7.83%-19.68%),and Actinobacteria(2.21%-16.4%).Compared with non-inoculation,different inoculation treatments can promote the increase of different beneficial bacteria,and thus have a certain promotion effect on alfalfa nutrient absorption and stress resistance.For example,inoculation with Chinese rhizobium increased alfalfa rhizosphere Alphaproteobacteria and other nitrogen cycling Bacterial abundance.Inoculation with Glomus intracellularis and Glomus Moses increased the abundance of beneficial bacteria such as Gammaproteobacteria and Bacteroidia that promote the phosphorus cycle in the rhizosphere of alfalfa.In addition,redundant analysis(RDA)showed that organic matter was the most influential on the bacterial community structure,and the correlations of p H,total potassium,and water content were second.(3)Using high-throughput sequencing technology to perform fungal ITS sequencing on alfalfa rhizosphere and non-rhizosphere soil samples at different periods without treatment,a total of 3 497 334 effective sequences were obtained from 16 groups(48)of soil samples,with an average length of 242.21 bp.A total of 563 species of fungi from 16 alfalfa,48 classes,11 orders,232 families,449 genera were detected in alfalfa soil samples.Among them,Ascomycota,Sordariomycetes,and Colletotrichum are the most dominant phylums,class,and genera in soil fungi,respectively.Compared with non-inoculation,inoculation with AM fungi and rhizobium increased the richness and diversity of soil fungal communities,and increased the abundance of biocontrol bacteria,nitrogen-fixing and phosphorus-dissolving bacteria in the presence of pathogenic bacteria.Redundant analysis(RDA)showed that the p H,water content and soil catalase were more relevant to the alfalfa rhizosphere fungal community.(4)This study used Tax4 Fun to predict the function of bacterial communities.The results show that the main functional genes in all samples are metabolic related functions,which account for the largest proportion,indicating that metabolism plays an extremely important role in the growth process of alfalfa.In this study,the ecological functions of soil fungi in different periods and different inoculation treatment groups were predicted by FUNGuild.From the perspective of nutrition type,saprophytic nutrition type is the most important type.Compared with non-inoculation,the relative abundance of pathogenic trophotypes in the soils of each group inoculated with AM fungi and rhizobium was significantly reduced,while the abundance of symbiotic trophic types was significantly increased,indicating that inoculation with AM fungi and rhizobium was beneficial to plant growth and more beneficial.To reduce the incidence of plant diseases.