| As an environmentally friendly fertilizer,biofertilizer is very important in the development of sustainable agriculture,and has received widespread attention and research.Beneficial rhizosphere microorganisms can interact well with plants,and actinomycetes are an important type of beneficial rhizosphere bacteria.At present,it is unclear whether there is a unified mechanism for actinomycete biological fertilizer to regulate the growth of different crops and the rhizosphere microbial community.In this study,the biofertilizer containing two strains of actinomycetes,Streptomyces pactum Act12 and Streptomycete rochei D74,was used as the research object.Through pot experiment and field experiment to study the growth-promoting effect of actinomycete biofertilizer on different crops,and use bioinformatics analysis methods to explore the effect of actinomycete biofertilizer on the rhizosphere microbial community and function of different crops.The main results are as follows:(1)Field and pot experiments were conducted to study the growth-promoting effects of actinomycete biofertilizer on different plants.The results showed that the application of actinomycete biofertilizer can significantly increase the yield of different plants,making the fruit weight of pepper,tomato,cucumber and sunflower more than the control.Increased by56.0%,24.1%,52.8% and 15.1%,and can promote the growth of the underground part of the plant.Compared with the control,the root dry weight of pepper,tomato,cucumber and sunflower increased by 100.0%,21.0%,14.0% and 17.8%,and for the growth of the above-ground part of the plant,it has a significant promotion effect on the pepper plant.The fresh and dry weight of the pepper plant(the ground part)all increased by 112.6%,and there is no significant growth promotion effect on the other plants.Therefore,actinomycetes biofertilizer can increase crop yield and promote plant root growth.(2)Using 16 S r DNA and ITS high-throughput sequencing technology to study the effect of actinomycete biofertilizer application on the rhizosphere microorganisms of different crops,The results showed that the actinomycete biofertilizer had no uniform effect on the alpha diversity of the rhizosphere microbial communities of different crops,significantly changed the beta diversity of the fungal community,and significantly increased the relative abundance of the Proteobacteria in the bacterial community(Increase 5.1%).In addition,through the screening of biomarkers,it was found that the actinomycete biofertilizer increased the relative abundance of beneficial bacteria,such as Chitinophaga,Pseudoxanthomonas and Blastococcus in the bacterial community,and Cercophora and Coprinellus in the fungal community,effectively reducing The relative abundance of pathogenic bacteria,such as Cladosporium and Gibberella in fungal communities,provides a benign microbial environment for plant roots and indirectly promotes plant growth.Therefore,actinomycetes biofertilizer can recruit beneficial microorganisms in the rhizosphere of crops,reduce the relative abundance of harmful microorganisms,thereby improving the structure of the rhizosphere microbial community and creating a suitable rhizosphere growth environment for crops.(3)The microbial co-occurrence network and ?NTI value were used to study the effect of actinomycete biofertilizer application on the interaction and assembly process of different crop rhizosphere microbial communities.The results showed that the average path length in the actinomycete biofertilizer treatment network increased by 120.9% compared with the control network,and the total number of connections,average connectivity and network density were reduced by 20.1%,22.6% and 45.8% respectively compared with the control network,indicating that the actinomycete biofertilizer After application,the interaction between microorganisms is reduced,and the types of key genera in the microbial community are changed,so that the group of pathogenic microorganisms in the key genera of rhizosphere soil,such as Gibberella,Cladosporium and Chryseobacterium,is reduced,thereby reducing the occurrence of plant diseases The odds indirectly promote plant growth.In addition,the application of actinomycete biofertilizer makes the fungal community assemble in a certain direction,and whether or not actinomycete biofertilizer is applied,the assembly of the bacterial community is dominated by a random process.Therefore,the treatment of actinomycetes biofertilizer reduces the complexity of the microbial co-occurrence network,reduces the interaction between microorganisms,indicates the benign development of the rhizosphere microbial environment,and can regulate the fungal community for directional assembly,which may explain the earlier Actinomycetes are related to the research on the prevention and control of soil-fax fungi diseases.(4)Using PICRUSt2 to predict the function of the bacterial community to study the effect of actinomycete biofertilizer on the potential function of the bacterial community,the results show that the application of actinomycete biofertilizer makes the bacterial community coenzyme M biosynthesis I,sucrose biosynthesis III,sucrose biosynthesis I(from photosynthesis),sucrose degradation II(sucrose synthase),sulfur reduction I(assimilatory),NAD salvage pathway II,and aromatic biogenic amine degradation(bacteria)pathways are enriched,and the superpathway of sulfur oxidation(Acidianus ambivalens)pathways are reduced and significantly changed The metabolic function of the bacterial community,including carbohydrate metabolism,energy metabolism and other functions,promotes the circulation of nutrient elements such as carbon and nitrogen.Therefore,actinomycete biofertilizer can significantly change the metabolic function of the bacterial community.By promoting the pathways related to the conversion of nutrient elements such as carbon and nitrogen,it may be beneficial to the absorption of elements by crops and the growth of crops.This study can provide a scientific basis for the rational application of actinomycete biofertilizer and its impact on farmland soil ecosystem in different areas. |
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