전지우 (숙명여자대학교)

강교빈 (숙명여자대학교)

강교빈 (숙명여자대학교)

전지우 (숙명여자대학교)

박은진 (숙명여자대학교)

Insects have developed chemical defense strategies through interactions with symbiotic microorganisms to survive in environments that are highly exposed to pathogenic microbes. In particular, the larvae of Agapanthia amurensis overwinter inside the stems of Erigeron annuus, during which they become vulnerable to infection by fungal pathogens. This study was based on the hypothesis that symbiotic bacteria residing on the larval surface of A. amurensis produce antifungal secondary metabolites that contribute to host defense. Bacterial strains isolated from the larval surface were evaluated for their ability to inhibit the germination of conidia from Beauveria bassiana, a well-known entomopathogenic fungus. Among them, one strain exhibited strong antifungal activity. The active strain was cultivated on a large scale, and its metabolites were extracted using organic solvents. Untargeted metabolomic analysis based on LC-MS/MS was conducted to investigate the chemical profile of the extract. A bioactivity-guided fractionation approach was employed to identify fractions exhibiting concentrated antifungal activity. Compound annotation is currently underway based on LC-MS/MS data, along with further purification and structural elucidation of the active metabolite. These ongoing analyses are expected to identify secondary metabolites with antifungal activity, thereby supporting the role of larval surface-associated symbionts in host defense. Ultimately, this study aims to elucidate the ecological function of symbiont-derived antifungal compounds and explore their potential as novel antibiotic candidates.​