The co-inoculation of H1 and Y1 promoted soybean [ (L.) ] growth and increased the relative abundance of beneficial microorganisms in rhizosphere and root.

Currently, plant growth-promoting rhizobacteria (PGPR) microbial inoculants are heavily used in agricultural production among which sp. and sp. are two excellent inoculum strains, which are widely used in plant growth promotion and disease control. However, few studies have been conducted on the combined use of the two bacteria. The aim of this study was to investigate the effects of co-inoculation of these two bacteria on soybean [ (L.) ] growth and physiological indexes and further study the effect of microbial inoculants on native soil bacterial communities and plant endophyte microbiota, especially microorganisms in rhizosphere and root. A pot experiment was conducted and four treatments were designed: group without any strain inoculant (CK); group inoculated with H1 inoculant (J); group inoculated with Y1 inoculant (Y) and group inoculated with equal volume of H1 inoculant and Y1 inoculant (H). Compared with CK, the three inoculant groups J, Y, and H exhibited improved soybean growth and physiological indexes, and group H was the most significant ( < 0.05). In terms of rhizosphere bacterial community structure, the relative abundance of native (9.31%) was higher in the H group than in the J (6.07%), Y (3.40%), and CK (5.69%) groups, which has potential value of disease suppression. Besides, compared with bacterial communities of the other three groups in soybean roots, group H increased the abundance of beneficial bacterial community for the contents of , , and significantly increased ( < 0.05). In conclusion, we found that the composite inoculum of H1 and Y1 could effectively promote soybean growth, increase yield and improve the beneficial bacterial community in root and rhizosphere and have certain value for soil improvement.