Abstract:Plant microbiome is an important factor in plant growth, stress resistance and disease prevention. In order to find the role of plant microbiome in promoting growth and improving root microecology of tobacco, in this study, culturable bacteria were isolated from the root surface of tobacco, and the growth promoting ability of different strains was determined. The results showed that: 1) 310 culturable strains were isolated from the root surface of tobacco, belonging to 31 genera, in which most are Bacillus and Pseudomonas. 2) Comparative analysis showed that Pseudomonas, Bacillus, Stenotrophomonas, and Dyadobacter are the common bacteria in tobacco root surface of different tested soils. 3) Within 16 strains obtained by further screening, 6 strains have the ability to fix nitrogen, 5 strains can produce siderophores, 4 strains can dissolve inorganic phosphorus, and 4 strains can produce IAA. 4) Pot experiment verified the growth promoting effect of the strains, the six strains increased the plant height, total fresh weight and underground dry weight by at least 35.1%, 27.9% and 30.7%, respectively, accounting for 37.5% of all inoculated strains. In short, a variety of strains with growth-promoting ability can be isolated from the root surface of tobacco, which provides a theoretical basis for the construction of microbial community to promote tobacco growth in the future.