| Abstract:Objective: To characterize the biology of gibberellin-producing endophytic fungi and evaluate their growth-promoting effects on Glycyrrhiza uralensis. Methods: A high gibberellin-producing endophytic fungus of licorice was screened by the Folin's reagent method, and this strain was identified by molecular characterization method. This strain of fungus was back-infected with the seedlings of G. uralensis to evaluate its effect on G. uralensis, and the biological characteristics of this strain were analyzed using different culture conditions. Results: A high gibberellin-producing fungus, A9, and the content of mycelial fermentation broth reached 0.478 mg·mL-1 at 140 r min-1 and 28℃ for 7 d of fermentation, was screened out. A9 was identified as Clonostachys rosea, and the optimal culture conditions were as follows: LB medium, fructose for carbon source, peptone for nitrogen source, light and dark alternately, and pH7. It had the following effects on G. uralensis at different growth periods (1, 3, 6 months old): the total length of plants at the age of 1 month was higher than that of the control group, the fresh weight of roots at the age of 3 months was higher than that of the control group, and the total length and dry weight of roots at the age of 6 months were higher than that of the control group. Conclusion: A9 has a wide range of adaptability, and can grow under a variety of carbon, nitrogen, medium and pH conditions, and has a certain growth-promoting effect on different stages of G. uralensis, which can promoted the development and utilization of microbial fertilizers based on A9. |
