Antifungal Activity of Natural Volatile Organic Compounds against Litchi Downy Blight Pathogen Peronophythora litchii

• Published in: Molecules (Basel, Switzerland) Switzerland), 2018-02, Vol.23 (2), p.358
• Main Authors: Xing, Mengyu, Zheng, Li, Deng, Yizhen, Xu, Dandan, Xi, Pinggen, Li, Minhui, Kong, Guanghui, Jiang, Zide
• Format: Article
• Language: English
• Subjects: Alcohol; Alcohols; Antifungal activity; Antifungal Agents - chemistry; Antifungal Agents - pharmacology; Appressoria; Biological activity; Biological control; Blight; Caryophyllene; Cell walls; Cytology; Deformation mechanisms; Electron microscopy; Fruits; Fungicides; Gas chromatography; Germination; Humulene; Hyphae; Infections; Litchi; Litchi - microbiology; litchi downy blight; Microbial Sensitivity Tests; Microscopy; Mode of action; Mycelia; Organic compounds; Pathogens; Peronophythora litchii; Phenylethyl alcohol; Phytophthora - drug effects; Phytophthora - ultrastructure; Plant Diseases - microbiology; Plant Diseases - prevention & control; Salicylic acid; Scanning electron microscopy; Spectrophotometry; Sporangia; Spores, Fungal - drug effects; Spores, Fungal - ultrastructure; Sporulation; Streptomyces fimicarius BWL-H1; Transmission electron microscopy; VOCs; Volatile compounds; Volatile organic compounds; Volatile Organic Compounds - chemistry; Volatile Organic Compounds - pharmacology; Volatiles
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules23020358

Litchi ( Sonn.) is a commercially important fruit but its production and quality are restricted by litchi downy blight, caused by the oomycete pathogen Chen. Volatile substances produced by a biocontrol antinomycetes BWL-H1 could inhibited growth and development both in vitro and in detached litchi leaf and fruit infection assay. Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) analyses indicated that volatile organic compounds (VOCs) from BWL-H1 resulted in severe damage to the endomembrane system and cell wall of cells in vitro and abnormal morphology of appressoria, as well as deformed new hyphae in infection process. VOCs could suppress mycelial growth, sporulation, while with no obvious effect on sporangia germination. Based on gas chromatography-mass spectrophotometric analyses, 32 VOCs were identified from BWL-H1, the most abundant of which was phenylethyl alcohol. Eight VOCs, including phenylethyl alcohol, ethyl phenylacetate, methyl anthranilate, α-copaene, caryophyllene, humulene, methyl salicylate and 4-ethylphenol, that are commercially available, were purchased and their bioactivity was tested individually. Except for humulene, the other seven tested volatile compounds shown strong inhibitory activity against mycelial growth, sporulation, sporangia germination and germ-tube growth of . Especially, 4-ethylphenol showed the highest inhibitory effect on sporulation at a very low concentration of 2 µL/L. Overall, our results provided a better understanding of the mode of action of volatiles from BWL-H1 on , and showed that volatiles from BWL-H1 have the potential for control of postharvest litchi downy blight.