Insights into antifungal mechanism of cumin aldehyde against Magnaporthe oryzae

BACKGROUND: Cumin essential oil from Cuminum cyminum is a promising alternative to synthetic fungicides because of its broad-spectrum antifungal activity and environmental compatibility. However, its major active constituent and antifungal mechanism remain unclear. Using Magnaporthe oryzae Guy11, the causal agent of rice blast as model, this study identified the major antifungal constituent of cumin essential oil and investigated its mode of action. RESULTS: Twelve major constituents were identified by gas chromatography-mass spectrometry, with cumin aldehyde as the predominant component (42.51%). Comparative antifungal assays showed that cumin aldehyde is the principal active constituent, which significantly inhibits mycelial growth, conidial germination, appressorium formation, and pathogenicity of M. oryzae. Microscopic analyses showed that cumin aldehyde disrupts membrane integrity, alters cell wall organization, and induces excessive reactive oxygen species accumulation in M. oryzae. Transcriptome analysis revealed marked changes in genes associated with cell wall biosynthesis, oxidative stress response, DNA replication, and protein glycosylation. Detached rice leaf assays further demonstrated protective and curative activities of 62.14% and 41.46%, respectively. CONCLUSION: Cumin aldehyde is the major antifungal constituent of cumin essential oil and suppresses M. oryzae through coordinated disruption of membrane integrity, oxidative homeostasis, and cellular metabolism. These findings provide new insights into the antifungal mechanism of cumin essential oil and support the potential application of cumin aldehyde as a botanical fungicide for rice blast management. © 2026 Society of Chemical Industry.