Fumigant Antifungal Activity via Reactive Oxygen Species of Thymus vulgaris and Satureja hortensis Essential Oils and Constituents against Raffaelea quercus-mongolicae and Rhizoctonia solani.

Kim Kim,Seo Seo,Park Park,Huh Huh,Lee Lee,Kwon Kwon

doi:10.3390/biom9100561

Kim Kim, Seo Seo + Show 4 more

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https://doi.org/10.3390/biom9100561

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Abstract

In this study, the fumigant antifungal activity of 10 Lamiaceae plant essential oils was evaluated against two phytopathogenic fungi, Raffaelea quercus-mongolicae, and Rhizoctonia solani. Among the tested essential oils, thyme white (Thymus vulgaris) and summer savory (Satureja hortensis) essential oils exhibited the strongest fumigant antifungal activity against the phytopathogenic fungi. We analyzed the chemical composition of two active essential oils and tested the fumigant antifungal activities of the identified compounds. Among the tested compounds, thymol and carvacrol had potent fumigant antifungal activity. We observed reactive oxygen species (ROS) generation in two fungi treated with thymol and carvacrol. Confocal laser scanning microscopy images of fungi stained with propidium iodide showed that thymol and carvacrol disrupted fungal cell membranes. Our results indicated that ROS generated by thymol and carvacrol damaged the cell membrane of R. querqus-mongolicae and R. solani, causing cell death.

Highlights

Oak wilt disease caused by a fungus that is symbiotic with ambrosia beetles is a serious problem in Korea [1]
We investigated the fumigant antifungal activities of 10 Lamiaceae plant essential oils and their constituents against two phytopathogenic fungi, R. quercus-mongolicae and R. solani
The phytopathogenic fungi Raffaelea quercus-mongolicae and Rhizoctonia solani were supplied by the National Institute of Forest Science, Seoul, the Republic of Korea

Summary

Introduction

Oak wilt disease caused by a fungus that is symbiotic with ambrosia beetles is a serious problem in Korea [1]. This disease was first recorded in Sungnam city, Gyeonggi Province, the Republic of Korea in 2004 and has spread to several regions of the Korean peninsula [2]. Raffaelea quercus-mongolicae (K.H. Kim, Y.J. Choi, & H.D. Shin) was identified as the fungal pathogen of oak wilt disease in 2009 [3]. The ambrosia beetle, Platypus koryoensis, transfers R. quercus-mongolicae to new oak trees when they attack the host tree for breeding. Quercus mongolicae (Fischer) is the main tree species attacked by

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