| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4506103 | Crop Protection | 2013 | 7 Pages |
The objectives of this study were to investigate the mechanisms of action and to evaluate the potential application of Desmos chinensis extracts for controlling rice sheath blight. The dichloromethane extract from D. chinensis demonstrated high antifungal activity against Rhizoctonia solani. The extract was shown to have anti-R. solani activity with minimum inhibitory concentration (MIC) and minimum fungicidal concentration values ranging from 31.2 to 62.5 μg mL−1 and from 62.5 to 500 μg mL−1, respectively. Bioautography on thin-layer chromatography plates demonstrated antifungal activity of the extract with an Rf value of 0.33. A total of 7 compounds, 2 benzoate esters (benzyl benzoate and benzyl 2-hydroxybenzoate), 2 sesquiterpenoids (α-eudesmol and β-eudesmol), 1 aromatic alcohol (benzyl alcohol), 1 aromatic ketone (acetophenone) and 1 diterpenoid (phytol), were detected and identified using gas chromatography–mass spectrometry analysis. Electron micrographs confirmed the effects of the extract on morphological and ultrastructural alterations in the treated fungal cells. The micrographs of the mycelia treated with the extract at 4MIC illustrated aberrant morphology such as shrinkage, partial distortion and globular structures of different sizes along the surface of the mycelia. Damaging membranous structures including disruption of the cell membrane, partial loss of nuclear membranes, and depletion of hyphal cytoplasm and membranous organelles were observed. Foliar application of D. chinensis extract at a concentration of 2 mg mL−1 on rice markedly decreased sheath blight severity. It was concluded that the application of D. chinensis extract can be used as a botanical fungicide to control rice sheath blight.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Desmos chinensis was effective against R. solani with an MIC value of 31.2 μg mL-1. ► Seven compounds were identified by TLC-bioautographic assay combined with GC–MS. ► SEM of mycelia treated with the extract at 4MIC showed aberrant surface morphology. ► TEM illustrated disruption of cell membrane and depletion of membranous organelles. ► Desmos extract could be considered as a potential source of antifungal compounds.
