Antifungal activity and mechanism of 4‐ethyl‐2‐methoxyphenol from <i>Ceriporia lacerata</i> <scp>HG2011</scp> against <i>Colletotrichum camelliae</i>

BACKGROUND: Colletotrichum camelliae is a major pathogen causing yield and quality losses in tea plants. Chemical control methods face challenges, including environmental concerns and drug resistance, therefore developing microbial-derived biological control agents has become a research priority. This study investigated the antifungal activity and mechanism of action of the volatile compound 4-ethyl-2-methoxyphenol derived from Ceriporia lacerata HG2011 against C. camelliae. RESULTS: concentration and the protective efficacy increased in a concentration dependent manner. Microscopic observations revealed that 4-ethyl-2-methoxyphenol induced mycelial folding, shrinkage, membrane rupture, disintegration and loss of continuity without damaging the cell wall. Further analysis indicated that the compound reduced the activity of antioxidant enzymes, leading to abnormal reactive oxygen species accumulation, increased malondialdehyde content, decreased ergosterol levels and disrupted cell membrane permeability and stability. Transcriptomic and qPCR analyses confirmed that 4-ethyl-2-methoxyphenol significantly affected the expression of genes involved in fatty acid synthesis and antioxidant enzyme pathways. In summary, 4-ethyl-2-methoxyphenol inhibits C. camelliae by disrupting the structure and function of fungal cell membranes and regulating oxidative stress-related pathways. CONCLUSION: This study provides a theoretical foundation and practical insights for developing novel biological control agents against tea anthracnose disease. © 2026 Society of Chemical Industry.