Study On Characteristics Of Soil Microorganism In Tobacco Field And Its Relationship With Bacterial Wilt

In this paper,the microbial quantity,diversity and community composition of tobacco soil were tested in Shaowu City,Fujian Province.The characteristics of soil microorganisms in tobacco fields under tobacco-rice rotation and different tobacco plant growth periods were analyzed.The relationship between soil microbes and tobacco bacterial wilt was discussed,which provided a theoretical basis for biological control of tobacco bacterial wilt and reduction of incidence.The specific research results are as follows:(1)Compared with the soil without tobacco planting,the soil microorganisms were affected by the growth of the tobacco plant after the tobacco planting,they were more active,and the quantity,diversity and richness were improved.For example,the abundance of Proteobacteria,Actinobacteria and Ascomycota was increased,while the abundance of Acidobacteria,Chloroflexi and norank-k-Fungi was decreased.(2)The number and community structure of rhizosphere soil microorganisms changed during the different growth period of tobacco plants.The vigorous growing period is the most obvious period of soil microbial change.The abundance changes of Proteobacteria and Ascomycota in soil were the most significant.Therefore,paying attention to the changes of soil microbes in the vigorous growing period is the key to understanding the relationship between soil microorganisms and tobacco bacterial wilt.(3)There were differences in microbial community structure in paddy fields and tobacco fields.Acidobacteria,Nitrospirae,Basidiomycota,and norank_k__Fungi were higher in paddy fields;while the abundance of Actinobacteria,Firmicutes,and Ascomycota is higher in tobacco fields.The difference of soil microbial community structure in soil may be the key to better control of tobacco bacterial wilt under tobacco-rice rotation.(4)There were differences in soil microbial community structure between healthy and diseased tobacco fields.The soil microbial diversity in healthy tobacco fields was higher than that in diseased tobacco fields,and the soil microbial diversity decreased when tobacco plants were infected by tobacco bacterial wilt.Proteobacteria and norank_k__fungi were abundant in healthy soil;Ascomycota and Saccharibacteria were abundant in the diseased soil.Microfoccales,Xanthomonadales,and Tremellomycetes microorganisms may be beneficial bacteria for inhibiting the pathogenesis of tobacco bacterial wilt by Multi-level species difference analysis,while Ascomycota may provide a pathway for the pathogenesis of tobacco bacterial wilt.The species selected by the random forest classification model can effectively distinguish between healthy and diseased tobacco fields.The selected species belong to Proteobacteria,which indicates that Proteobacteria can be used as an indicator for evaluating healthy tobacco fields.(5)The active of roots of tobacco plants make it easier for tobacco fields to enrich pathogens.Therefore,taking measures to increase the abundance of beneficial microorganisms and microorganisms diversity in the soil is the fundamental method to improve soil health quality and micro-ecological environment,but also prevent and control tobacco bacterial wilt.