Antifungal activity of Bunium persicum essential oil and its constituents on growth and pathogenesis of Colletotrichum lindemuthianum

Anthracnose disease caused by Colletotrichum lindemuthianum (Sacc. and Magnus) Lams- -Scrib is one of the most devastating seed-borne diseases of common bean (Phaseolus vulgaris L.). In the present study, we evaluated the antifungal activity of Bunium persicum essential oil (EO) and its main constituents on mycelial growth, sporulation and spore germination inhibition of C. lindemuthianum. The main objective of this study was to investigate the effect of EO and its main constituents on decreasing the activity of cell wall degrading enzymes (CWDEs) produced by C. lindemuthianum, which are associated with disease progress. Also, the effects of seed treatment and foliar application of EO and its main constituent, cuminaldehyde, on anthracnose disease severity was investigated. The essential oil of B. persicum, was obtained by using a clevenger apparatus and its major constituents were identified by gas chromatography-mass spectrometry (GC-MS). The EO was characterized by the presence of major compounds such as cuminaldehyde (37.7%), γ-terpinene (17.1%) and β-pinene (15.4%), which indicated antifungal effects against C. lindemuthianum. This pathogen did not grow in the presence of EO, cuminaldehyde and γ-terpinene, β-pinene at 1,500; 1,010 and 1,835 ppm concentrations, respectively. Also, sporulation and spore germination of C. lindemuthianum was completely inhibited by EO and cuminaldehyde. Synergistic effects of the main constituents showed that combing γ-terpinene with cuminaldehyde induced a synergistic activity against C. lindemuthianum and in combination with β-pinene caused an additive effect. Activities of pectinase, cellulase and xylanase, as main CWDEs, were decreased by EO and its main constituents at low concentration without affecting mycelial growth. Seed treatment and foliar application of peppermint EO and/or cuminaldehyde significantly reduced the development of bean anthracnose. We introduced B. persicum EO and constituents, cuminaldehyde and γ-terpinene, as possible control agents for bean anthracnose.