Abstract: The aim of this study was to study the physiological function of PDIDSM_85260 in the growth of Penicillium digitatum. The effect of silencing of gene PDIDSM_85260 was investigated on the growth characteristics of Penicillium digitatum under normal and stress conditions by measuring mycelial growth and spore germination. Microscopy characterization showed that PDIDSM _ 85260 silencing had no effect on spore germination and mycelial morphology under normal growth conditions. However, the silence of the gene PDIDSM_85260 leaded to the increase of growth rate of Penicillium digitatum. In addition, the responses of Penicillium digitatum upon ions (Na⁺, K⁺, Mg²⁺, Cu²⁺, Fe²⁺, Ca²⁺) and H₂O₂ stress were also evaluated. Compared with the wild-type strain, silencing of the PDIDSM _85260 gene increased the sensitivity to the stress of extracellular K⁺, Na⁺, Fe²⁺, Ca²⁺, demonstrating that PDIDSM_85260 may be involved in the response of Penicillium digitatum to ions stress. Also, the high concentrations of H₂O₂ significantly inhibited the growth of Penicillium digitatum, and PDIDSM_85260 silencing increased the sensitivity to the stress of H₂O₂. Therefore, PDIDSM_85260 may participate in the maintenance of reactive oxygen species and oxidative stress. In summary, this study suggested that the transcription factor PDIDSM _85260 may play an important role in the growth of Penicillium digitatum, maintenance of ionic homeostasis, resistance to reactive oxygen species and oxidative stress. This study provided a foundation for further study on the function of PDIDSM_85260 in Penicillium digitatum.