Study on Microbial Community Composition in Rhizosphere Soil of Tobacco Fields with Different Disease Incidence Rates

To effectively prevent the occurrence of soil-borne diseases, 16S rRNA and 18S rRNA gene sequences were used to analyze the differences in microbial community composition between rhizosphere soils of healthy and susceptible tobacco fields during the mature period, and the correlations between physicochemical properties, enzyme activity and microorganisms were studied. The results showed that norank_p_Saccharibacteria, norank_o_Gaiellales, Nocardioides, norank_o_Sordariales and Pseudallescheria were the key genus causing differences in microbial community composition between healthy and susceptible tobacco fields. There were significant differences in organic matter, total phosphorus, total nitrogen, available phosphorus, alkaline nitrogen, protease, urease, catalase and phosphatase in the soils of healthy and susceptible tobacco fields. And the correlations between rhizosphere microbial and soil properties in tobacco fields are the following:Nocardioides was significantly positively correlated with organic matter (r=0.943), phosphatase (r=0.941), was significantly negatively correlated with catalase (r=-0.880) and protease (r=-0.829). norank_o_Sordariales was significantly positively correlated with organic matter (r=0.829), total phosphorus (r=0.943), alkaline nitrogen (r=0.943), urease (r=0.943), and extremely significantly negative correlation with catalase (r=-0.941). The results provide a theoretical basis for controlling soil-borne diseases of tobacco by regulating the structure of microbial communities.