不同微生物菌剂对植烟土壤微生物群落结构及功能的影响OA

The study aimed to explore the effects of microbial agents on the physicochemical properties,microbial community structure and function of tobacco-planting soil.The tobacco-cultivated soil in Guizhou province was selected as the experimental subject.Different microbial agent treatments were established:no application of microbial agents(CK),Trichoderma harzianum(M1),Bacillus subtilis(M2),and Pseudomonas fluorescens(M3).Rhizosphere soils were collected to determine soil physicochemical properties,while high-throughput sequencing technology was employed to analyze the effects of microbial agents on soil microbial community structure and function.The results showed that the application of microbial agents significantly enhanced various agronomic traits of flue-cured tobacco.The M3 treatment exhibited the stem circumference,maximum leaf length,maximum leaf width,and number of leaves,showing significant increases of 5.7％,8.3％,11.8％,and 11.7％,respectively,compared to the CK treatment.Under M2 treatment,the potassium content in tobacco leaves increased significantly by 18.11％compared to the CK treatment.The nicotine content in M1,M2,and M3 treatments decreased by 11.28％,27.27％,and 11.59％,respectively,compared to the CK treatment.This indicates that the application of microbial inoculate promoted the growth of flue-cured tobacco and enhanced the quality of tobacco leaves.M2 treatment significantly increased soil available phosphorus and available potassium content,representing increases of 33.12％and 8.89％respectively compared to the CK treatment,thereby enhancing soil nutrient content.Microbial inoculate increased soil bacterial diversity and abundance indices while decreasing fungal diversity and abundance indices.In bacterial communities,the application of microbial inoculants increased the relative abundance of dominant phyla and genera such as Proteobacteria,Actinobacteria,Gemmatimonadota,Gemmatimonas,and Sphingomonas.In fungal communities,the relative abundances of Basidiomycota in M1,M2,and M3 treatments increased by 39.36％,7.45％,and 56.38％,respectively,compared to the CK treatment.M2 and M3 treatments reduced the relative abundance of potential pathogens such as Fusarium.Additionally,microbial inoculate increased the number of nodes,edges,and average degree in the soil bacterial co-occurrence network,rendering it more complex and tightly connected.They also enhanced the modularity of the fungal occurrence network,thereby strengthening its stability.M1 and M3 treatments enhanced bacterial nitrate respiration and nitrogen respiration functions.All microbial inoculate treatments increased the relative abundance of soil fungi with plant-decaying and wood-decaying functions.Correlation analyses revealed that pH,available phosphorus,and organic matter emerged as key environmental factors significantly influencing soil bacterial community structure.Meanwhile,available phosphorus and total nitrogen were identified as primary environmental drivers shaping soil fungal community structure.In summary,microbial agents could enhance soil nutrient content,improve soil microbial community structure,increase the relative abundance of dominant bacteria in the soil,and reduce the relative abundance of potentially harmful bacteria,thereby creating a favorable micro-ecological soil environment for flue-cured tobacco growth and ultimately improving both yield and quality of the crop.