To address the current status of soil phosphorus deficiency， this study aimed to develop novel， safe， and efficient microbial fertilizers. Polygonatum cirrhifolium from Tibet was used as the test material， and the streak plate method was employed to isolate and screen phosphorus-solubilizing strains. Their phosphorus-solubilizing capacity was determined， and the culture conditions were investigated. The results showed that a total of 9 phosphorus-solubilizing bacterial strains were isolated. Among them， 5 strains with a phosphate solubilization index （PSI）>2.0 were screened， with phosphorus-solubilizing capacities ranging from 29.603 to 41.730 mg·L^-1. The strains were identified as follows： JYHJ-1 as Pseud-omonas yamanorum， JYHJ-2 as Pseudomonas koreensis， JYHJ-3 as Serratia proteamaculans， JYHJ-4 as Pseudomonas azotoformans， and JYHJ-5 as Microbacterium oxydans. Strain JYHJ-3 exhibited the strongest phosphorus-solubilizing ability， and it could secrete 7 types of organic acids as well as possess capabilities such as siderophore production， potassium solubilization， nitrogen fixation， and indole-3-acetic acid （IAA） production. In the single-factor experiments， the optimal phosphorus-solubilizing efficiency was achieved when lactose was used as the carbon source， ammonium acetate as the nitrogen source， initial pH was 5.5， inoculation volume was 2%， and NaCl concentration was 1%. Based on the single-factor experiments， response surface methodology （RSM） was applied to optimize the initial pH， inoculation volume， and NaCl concentration. The final optimal culture conditions were determined as follows： lactose as the carbon source， ammonium acetate as the nitrogen source， initial pH 5.5， inoculation volume 3%， and NaCl concentration 1%. In conclusion， the rhizosphere of Polygonatum cirrhifolium was rich in phosphorus-solubilizing bacterial resources. This study provided strain resources and a theoretical basis for the sustainable cultivation of medicinal Polygonatum cirrhifolium and the development of microbial fertilizers.

Polygonatum cirrhifolium  /  Rhizosphere bacteria  /  Phosphate-solubilizing capacity  /  Fermentation conditions