Effects Of Artificially Synthesized Microbial Communities On The Growth Of Corn And Tomato,as Well As Soil Bacterial Communities

The construction of microbial communities has always been the core content of research in the field of environmental microbiology,and has a long history in environmental microbiology research.China has been planting corn on a large scale all year round,second only to rice and wheat,and is the third largest grain crop;Tomatoes were originally grown in subtropical regions of the Americas,with high nutritional value and good fruit taste,and are cultivated worldwide.With the development of animal husbandry and the adjustment of agricultural industrial structure,the development of tomatoes and corn is of great significance for the development of the entire agricultural economy and the improvement of farmers’ income.In recent years,due to the excessive use of chemical fertilizers,the soil microenvironment has been affected,and the yield of tomato and corn has been limited.A large number of studies have shown that soil microorganisms can improve the soil microenvironment.Soil microorganisms act as decomposer,producers,and consumers in the ecosystem to provide nutrients for plants and soil animals,colonize plants,and promote plant growth and development.However,different growth promoting bacteria have different effects on plants.This study constructs an artificially synthesized microbial community and explores the optimal culture medium and conditions for microbial communities.The pot experiment of maize and tomato was used to evaluate the growth promoting effect of synthetic microbial community,determine the plant height,chlorophyll and related enzyme activities in tomato and maize at different stages,determine the soil available nutrients and soil urease to observe the impact of inoculation on soil nutrients,and use high-throughput sequencing to analyze the impact of different treatments on rhizosphere soil microbial community of different plants.The research results indicate that:1.A preliminary screening was conducted to obtain 33 strains with the functions of promoting phosphorus solubilization,nitrogen fixation,and iron carrier.The re screening results obtained 5 strains with the functions of phosphorus solubilization,nitrogen fixation,iron carrier,and IAA production.Through the interaction experiment of 5 strains,the combination relationship between the strains and the arrangement and combination method were explored to screen the combination bacteria.Seven combination bacteria were obtained,and the effective phosphorus and IAA content of single bacteria and 7 combination bacteria were measured,The effective phosphorus and IAA content of the 5 mixed strains were significant.The microbial community of the 5 strains was constructed and grew well in TSB medium.2.Bacterial inoculation affects the plant height,chlorophyll,soil nutrients,and soil urease activity of tomato and corn plants.After bacterial treatment,the content of soil available nutrients,including alkaline hydrolyzed nitrogen,available phosphorus,and available potassium,was significantly increased.The highest content of soil available nutrients was found in the synthetic microbial community;And it affects the enzyme activity in the rhizosphere soil of plants,such as soil urease.The highest urease activity in the soil after bacterial inoculation is in the synthetic microbial community.3.By using high-throughput sequencing technology,the full length sequence of 16 Sr RNA of rhizosphere bacteria in maize and tomato soil was determined,and the bacterial diversity and community structure composition of maize and tomato rhizosphere soil treated with different bacteria were analyzed.The diversity structure showed that the Diversity index of synthetic microbial community in tomato and maize plants was the highest.The composition of bacterial community in rhizosphere soil was analyzed.It was found that the dominant bacteria in soil samples were Acidobacteriota and Bacillota,and the dominant bacteria were Pseudomonas and Bacteroidota.In summary,the application of growth promoting bacteria can promote the growth of different crops and improve the soil environment of crops.By affecting the diversity of soil bacterial communities and promoting the colonization of dominant bacterial populations in the rhizosphere,it promotes plant growth and development.The results of this study can provide experimental basis and theoretical data for the application of different growth promoting strains in tomato and corn cultivation and the development of microbial fertilizers.