Characterization of Volatile Organic Compounds Emitted from Endophytic Burkholderia cenocepacia ETR-B22 by SPME-GC-MS and Their Inhibitory Activity against Various Plant Fungal Pathogens

Abstract

The use of antagonistic microorganisms and their volatile organic compounds (VOCs) to control plant fungal pathogens is an eco-friendly and promising substitute for chemical fungicides. In this work, endophytic bacterium ETR-B22, isolated from the root of Sophora tonkinensis Gagnep., was found to exhibit strong antagonistic activity against 12 fungal pathogens found in agriculture. Strain ETR-B22 was identified as Burkholderia cenocepacia based on 16S rRNA and recA sequences. We evaluated the antifungal activity of VOCs emitted by ETR-B22. The VOCs from strain ETR-B22 also showed broad-spectrum antifungal activity against 12 fungal pathogens. The composition of the volatile profiles was analyzed based on headspace solid phase microextraction (HS-SPME) gas chromatography coupled to mass spectrometry (GC-MS). Different extraction strategies for the SPME process significantly affected the extraction efficiency of the VOCs. Thirty-two different VOCs were identified. Among the VOC of ETR-B22, dimethyl trisulfide, indole, methyl anthranilate, methyl salicylate, methyl benzoate, benzyl propionate, benzyl acetate, 3,5-di-tert-butylphenol, allyl benzyl ether and nonanoic acid showed broad-spectrum antifungal activity, and are key inhibitory compounds produced by strain ETR-B22 against various fungal pathogens. Our results suggest that the endophytic strain ETR-B22 and its VOCs have high potential for use as biological controls of plant fungal pathogens.

Microbe Related Chemical Signalling and Its Application in Agriculture

“…B. cenocepacia regulates bacterial pathogenicity through two different types of QS systems including AHL and the cis -2-dodecenoic acid (BDSF) system [ 92 ]. These two QS systems have combined effects on biofilm formation, virulence factor production, and bacterial motility in B. cenocepacia [ 93 ]. Study by Chen et al, (2020) has also shown that B. cenocepacia produced various volatile organic compounds (VOCs) such as indole, dimethyl trisulfide, allyl benzyl ether and methyl benzoate that have antifungal activity against different types of fungal pathogens including Botrytis cinerea, Alternaria alternata and Bipolaris sorokiniana [ 93 ].…”

“…These two QS systems have combined effects on biofilm formation, virulence factor production, and bacterial motility in B. cenocepacia [ 93 ]. Study by Chen et al, (2020) has also shown that B. cenocepacia produced various volatile organic compounds (VOCs) such as indole, dimethyl trisulfide, allyl benzyl ether and methyl benzoate that have antifungal activity against different types of fungal pathogens including Botrytis cinerea, Alternaria alternata and Bipolaris sorokiniana [ 93 ]. Other authors also have reported similar results using different Burkholderia spp.…”

The Role of Endophytes in Combating Fungal- and Bacterial-Induced Stress in Plants

“…Burkholderia cenocepacia ETR-B22 of Sophora tonkinensis produces VOCs such as nonanoic acid, benzyl propionate, benzyl acetate, dimethyl trisulfide, methyl anthranilate, methyl salicylate, methyl benzoate, 3,5-di-tert-butyl phenol, and allyl benzyl ether. The bacteria show a wide array of antifungal activities against 12 fungal pathogens, namely Alternaria alternata, Aspergillus niger, Bipolaris sorokiniana, Botrytis cinerea, Fusarium oxysporum, Fusarium solani, Fusarium fujikuroi, Helminthosporium torulosum, Mycosphaerella fijensis, Magnaporthe oryzae Phyllosticta zingiber , and Rhizoctonia solani , which cause several infections in plants [ 99 ].…”

The Role of High-Resolution Analytical Techniques in the Development of Functional Foods

“…A condition for GC analyses is that the analytes must be volatile enough to be able to be separated and detected. For this reason, many of the GC applications have been based on the characterization of the volatile compounds fractions of different plant or food matrices [ 23 , 24 , 25 ]. However, several non-volatile compounds can be derivatized prior to analysis in order to increase its volatility.…”