Interference and Mechanism of Dill Seed Essential Oil and Contribution of Carvone and Limonene in Preventing Sclerotinia Rot of Rapeseed

Bingxin Ma,Xiaoquan Ban,Bo Huang,Yuxin Chen,Jingsheng He,Youwei Wang,Hong Zeng,Jun Tian,Zonghua Wang

doi:10.1371/journal.pone.0131733

Abstract

This study aimed to evaluate the inhibitory effects of dill (Anethum graveolens L.) seed essential oil against Sclerotinia sclerotiorum and its mechanism of action. The antifungal activities of the two main constituents, namely carvone and limonene, were also measured. Mycelial growth and sclerotial germination were thoroughly inhibited by dill seed essential oil at the 1.00 μL/mL under contact condition and 0.125μL/mL air under vapor condition. Carvone also contributed more than limonene in inhibiting the growth of S. sclerotiorum. Carvone and limonene synergistically inhibited the growth of the fungus. In vivo experiments, the essential oil remarkably suppressed S. sclerotiorum, and considerable morphological alterations were observed in the hyphae and sclerotia. Inhibition of ergosterol synthesis, malate dehydrogenase, succinate dehydrogenase activities, and external medium acidification were investigated to elucidate the antifungal mechanism of the essential oil. The seed essential oil of A. graveolens can be extensively used in agriculture for preventing the oilseed crops fungal disease.

Highlights

Sclerotinia sclerotiorum (Lib.) de Bary is a soil-borne plant pathogen that has caused significant damage on most vegetables, oil crops [1,2]
Synthetic chemical fungicides currently used are harmful to the public health
Gas chromatography (GC)-MS analysis of dill seed essential oil showed that the major compounds identified with GC were carvone (41.51%) and limonene (32.63%)

Summary

Introduction

Sclerotinia sclerotiorum (Lib.) de Bary is a soil-borne plant pathogen that has caused significant damage on most vegetables, oil crops [1,2]. This fungus is homothallic and does not produce asexual spores [3]. Naturally developed substances have increased because of the negative effects of misuse and overuse of synthetic chemical fungicides and fertilizers; these disadvantages include fungicide resistance, toxic residues, and negative environmental effects [4, 5]. The use of naturally derived compounds, such as essential oils and plant extracts, as potential fungicides has greatly increased [6]. Rapeseed (Brassica napus L.) is grown for the PLOS ONE | DOI:10.1371/journal.pone.0131733 July 2, 2015

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