Screening and identification of three strains of phosphate-solubilizing bacteria from maize rhizosphere and their roles in plant growth promoting effect

In order to obtain excellent plant-growth promoting bacteria and to investigate their promoting effects on maize plants, in this study, three strains of phosphate-dissolving bacteria with strong phosphate-dissolving ability were screened from the rhizosphere soil of maize plants using solid media of organic and inorganic phosphorus. Based on bacterial morphological identification and 16S rRNA gene sequence analysis, strain A23 was identified as Enterobacter asburiae, A24 as Enterobacter mori, and H10 as Enterobacter kobei. The results showed that strains A23, A24 and H10 had the capacity to dissolve organic phosphorus ranging from 146.19 to 158.52 μg·mL^-1; and the capacity to dissolve inorganic phosphorus ranging from 132.29 to 339.18 μg·mL^-1. The three strains also had the ability to produce siderophore, synthesize zeatin and auxin, and produce different types and levels of organic acids. The height, stem circumference, dry weight, and fresh weight of the maize plant increased by 36.99%, 21.32%, 170.14%, and 102.11%, respectively. Therefore, the three phosphatedissolving bacteria could provide a theoretical basis for the development and application of plantpromoting bacterial agents.