Background: Hyalodendriella sp. Ponipodef12, an endophytic fungus from a poplar hybrid, was a high producer of botrallin and TMC-264 with various bioactivities. In this study, the influences of eight metal ions (i.e., Mn^2 +, Na⁺, Mg^2 +, Zn^2 +, Cu^2 +, Fe^2 +, Fe^3 + and Al^3 +) on botrallin and TMC-264 production in liquid culture of the endophytic fungus Hyalodendriella sp. Ponipodef12 were investigated.

Results: Three most effective metal ions (Zn^2 +, Cu^2 + and Mg^2 +) along with their optimum concentrations were screened. The optimum addition time and concentrations of Zn^2 +, Cu^2 + and Mg^2 + were further obtained respectively for improving botrallin and TMC-264 production. The combination effects of Zn^2 +, Cu^2 + and Mg^2 + on the production of botrallin and TMC-264 by employing statistical method based on the central composite design (CCD) and response surface methodology (RSM) were evaluated, and two quadratic predictive models were developed for botrallin and TMC-264 production. The yields of botrallin and TMC-264, which were predicted as 144.12 mg/L and 36.04 mg/L respectively, were validated to be 146.51 mg/L and 36.63 mg/L accordingly with the optimum concentrations of Zn^2 + at 0.81 mmol/L, Cu^2 + at 0.20 mmol/L, and Mg^2 + at 0.13 mmol/L in medium.

Conclusion: The results indicated that the enhancement of botrallin and TMC-264 accumulation in liquid culture of the endophytic fungus Hyalodendriella sp. Ponipodef12 by the metal ions and their combination should be an effective strategy.