Effect of Atractylodes essential oil on different Colletotrichum species causing tea brown blight disease

Abstract

As a traditional Chinese medicine, atractylodes has the potential to be an antifungal agent for controlling fungal diseases. Essential oils with the advantage of vapor phase bioactivity makes them have wider potential applications. In this study, 5 different species in genus Colletotrichum causing tea brown blight disease were firstly employed to investigate the antifungal activities of atractylodes essential oil (AO) by direct contact and fumigation methods. Our results indicated that the tested AO had significantly higher antifungal effect in contact phase than that in vapor phase (P < 0.05). It is important that AO showed different antifungal activities against C. karstii, C. gloeosporioides, C. camelliae, C. fioriniae and C. chongqingense with EC50 of 0.089, 0.165, 0.108, 0.205 and 0.092 mg·mL−1, respectively. The growth of Colletotrichum species were all inhibited by influencing the morphology of conidia and hyphae, damaging the cell walls and then increasing the membrane permeability. After AO treatment, total 949 up-regulated and 1360 down-regulated genes were detected in treated C. gloeosporioides, and the significantly differential genes were mainly related to ABC transporters, MFS transporters and cytochrome P450s. KEGG pathways analysis revealed the significantly differential genes were mainly enriched in carbohydrate metabolism especially fructose and mannose metabolism, which may act as the main energy source for the activities of fungi. Five differential genes related to ABC, MFS and CYP families showed significantly different expression levels among different Colletotrichum species by qRT-PCR analysis. This study fully reveals the differential antifungal activities and mechanism of different Colletotrichum species against AO.