Study On Mixes Of Bacteria And Soil Colonization Carriers Of Soybean Plant Growth-promoting Rhizobacteria Inoculants

Plant rhizosphere microbial communities play an important ecological functions through interactions with plants.However,the construction mechanism and function of the rhizosphere microbial community are still unclear,and there are few studies on the succession mode of the rhizosphere microbial community in the time series of plant growth and its impact on plants.Based on a large number of soybean rhizosphere strains in different periods isolated and obtained by culturomics in the previous stage,this study constructed the core microbial synthetic community of soybean rhizosphere in different periods by analyzing the community succession characteristics and screening the core microorganisms in time series.Plant inoculation experiments were carried out using these core microbial communities to explore the effects of core communities on soybean plants in different periods,and to analyze the effect of vectors on community stability.The result is as follows1.By analyzing the culturomics data,72 strains were screened to form the core microbial community in the time series.Through the analysis of the core microbial community,it is shown that the alpha diversity and beta diversity of the core community can be consistent with the complete community in different treatment samples,and the species abundance of the core community can account for the vast majority of the overall community..The co-occurrence network analysis also showed that the core microbes did play an important role in the association of the overall community.The core community was strongly represented in both the sequencing data-based community and the culturomics data-based community.2.Through the plant inoculation experiments of the artificial rhizosphere core artificial community in different periods,it was found that although the species composition of each community was the same,the difference in species abundance would have a significant impact on plant growth,especially the w0 community and w7 community.Further transcriptome analysis found that the w0 community up-regulated plant photosynthesis and promoted plant growth,and its inoculated soybean plants had higher dry weight.The up-regulation of jasmonic acid-related genes reflects that the w0 community induces jasmonic acid-mediated signaling,which may induce plant resistance,and also reflects the interaction between bacteria and plants.The w7 community up-regulates genes related to IAA synthesis,inhibits nodulation,and promotes cell wall synthesis,which may make the IAA concentration in plants exceed the optimal level,resulting in lower dry weight of inoculated plants with w7 community.Inoculation of w7 strains down-regulated abscisic acid-related genes and protein phosphorylation in soybean plants,which may indicate a decrease in plant defense levels.3.Through the artificially synthesized homogenized bacterial colony inoculation carrier experiments,it was found that the influence of different carrier combinations on the stability of the colony was significantly different.The orthogonal experiments of the homogenized community combined with the carrier determined that the attapulgite0.5 m L,the diatomite 1 m L and the corn stalk 2 m L were the optimal combinations.The artificial synthetic rhizosphere microbial community constructed in this study has a good representativeness.Through the study of these communities,the differences in the effects of soybean rhizosphere communities on plants in different periods were revealed,and the effects of different carriers on the community stability were discussed.Subsequent studies on microbial plant interactions and root exudates also provide a basis for further optimization of the subsequent carrier.