Identification of Volatile Organic Compounds in Extremophilic Bacteria and Their Effective Use in Biocontrol of Postharvest Fungal Phytopathogens

Phytopathogenic fungal growth in postharvest fruits and vegetables is responsible for 20–25% of production losses. Volatile organic compounds (VOCs) have been gaining importance in the food industry as a safe and ecofriendly alternative to pesticides for combating these phytopathogenic fungi. In this study, we analysed the ability of some VOCs produced by strains of the genera Bacillus, Peribacillus, Pseudomonas, Psychrobacillus and Staphylococcus to inhibit the growth of Alternaria alternata, Botrytis cinerea, Fusarium oxysporum, Fusarium solani, Monilinia fructicola, Monilinia laxa and Sclerotinia sclerotiorum, in vitro and in vivo. We analysed bacterial VOCs by using GC/MS and 87 volatile compounds were identified, in particular acetoin, acetic acid, 2,3-butanediol, isopentanol, dimethyl disulphide and isopentyl isobutanoate. In vitro growth inhibition assays and in vivo experiments using cherry fruits showed that the best producers of VOCs, Bacillus atrophaeus L193, Bacillus velezensis XT1 and Psychrobacillus vulpis Z8, exhibited the highest antifungal activity against B. cinerea, M. fructicola and M. laxa, which highlights the potential of these strains to control postharvest diseases. Transmission electron microscopy micrographs of bacterial VOC-treated fungi clearly showed antifungal activity which led to an intense degeneration of cellular components of mycelium and cell death.

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Antifungal properties of volatile organic compounds produced by Daldinia eschscholtzii MFLUCC 19-0493 isolated from Barleria prionitis leaves against Colletotrichum acutatum and its post-harvest infections on strawberry fruits

PeerJ ◽

10.7717/peerj.11242 ◽

2021 ◽

Vol 9 ◽

pp. e11242

Author(s):

Sarunpron Khruengsai ◽

Patcharee Pripdeevech ◽

Chutima Tanapichatsakul ◽

Chanin Srisuwannapa ◽

Priya Esilda D’Souza ◽

...

Keyword(s):

Antifungal Activity ◽

Volatile Organic Compounds ◽

Organic Compounds ◽

Endophytic Fungi ◽

Colletotrichum Acutatum ◽

Anthracnose Disease ◽

Post Harvest ◽

Volatile Organic

Fungal endophytes are microorganisms living symbiotically with a host plant. They can produce volatile organic compounds (VOCs) that have antimicrobial activity. This study aimed to isolate endophytic fungi from Barleria prionitis plants grown in Thailand and to investigate the antifungal properties of their VOCs against Colletotrichum acutatum, a causal agent of anthracnose disease on post-harvest strawberry fruits. A total of 34 endophytic fungi were isolated from leaves of B. prionitis. The VOCs produced from each individual isolate were screened for their antifungal activity against C. acutatum using a dual-culture plate method. From this in vitro screening experiment, the VOCs produced by the endophytic isolate BP11 were found to have the highest inhibition percentage (80.3%) against the mycelial growth of C. acutatum. The endophytic isolate BP11 was molecularly identified as Daldinia eschscholtzii MFLUCC 19-0493. This strain was then selected for an in vivo experiment. Results from the in vivo experiment indicated that the VOCs produced by D. eschscholtzii MFLUCC 19-0493 were able to inhibit infections by C. acutatum on organic fresh strawberry fruits with an average inhibition percentage of 72.4%. The quality of the pathogen-inoculated strawberry fruits treated with VOCs produced by D. eschscholtzii MFLUCC 19-0493 was evaluated. Their fruit firmness, total soluble solids, and pH were found to be similar to the untreated strawberry fruits. Solid phase microextraction-gas chromatographic-mass spectrometric analysis of the VOCs produced by D. eschscholtzii MFLUCC 19-0493 led to the detection and identification of 60 compounds. The major compounds were elemicin (23.8%), benzaldehyde dimethyl acetal (8.5%), ethyl sorbate (6.8%), methyl geranate (6.5%), trans-sabinene hydrate (5.4%), and 3,5-dimethyl-4-heptanone (5.1%). Each major compound was tested for its antifungal activity against C. acutatum using the in vitro assay. While all these selected VOCs showed varying degrees of antifungal activity, elemicin was found to possess the strongest antifungal activity. This work suggests that D. eschscholtzii MFLUCC 19-0493 could be a promising natural preservative for controlling C. acutatum associated anthracnose disease in strawberry fruits during the post-harvest period.

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Trichoderma asperellum T76-14 Released Volatile Organic Compounds against Postharvest Fruit Rot in Muskmelons (Cucumis melo) Caused by Fusarium incarnatum

Journal of Fungi ◽

10.3390/jof7010046 ◽

2021 ◽

Vol 7 (1) ◽

pp. 46

Author(s):

Warin Intana ◽

Suchawadee Kheawleng ◽

Anurag Sunpapao

Keyword(s):

Volatile Organic Compounds ◽

Organic Compounds ◽

Cucumis Melo ◽

Fungal Growth ◽

Fruit Rot ◽

Postharvest Disease ◽

Dual Culture ◽

Trichoderma Asperellum ◽

Volatile Organic

Postharvest fruit rot caused by Fusarium incarnatum is a destructive postharvest disease of muskmelon (Cucumis melo). Biocontrol by antagonistic microorganisms is considered an alternative to synthetic fungicide application. The aim of this study was to investigate the mechanisms of action involved in the biocontrol of postharvest fruit rot in muskmelons by Trichoderma species. Seven Trichoderma spp. isolates were selected for in vitro testing against F. incarnatum in potato dextrose agar (PDA) by dual culture assay. In other relevant works, Trichoderma asperellum T76-14 showed a significantly higher percentage of inhibition (81%) than other isolates. Through the sealed plate method, volatile organic compounds (VOCs) emitted from T. asperellum T76-14 proved effective at inhibiting the fungal growth of F. incarnatum by 62.5%. Solid-phase microextraction GC/MS analysis revealed several VOCs emitted from T. asperellum T76-14, whereas the dominant compound was tentatively identified as phenylethyl alcohol (PEA). We have tested commercial volatile (PEA) against in vitro growth of F. incarnatum; the result showed PEA at a concentration of 1.5 mg mL−1 suppressed fungal growth with 56% inhibition. Both VOCs and PEA caused abnormal changes in the fungal mycelia. In vivo testing showed that the lesion size of muskmelons exposed to VOCs from T. asperellum T76-14 was significantly smaller than that of the control. Muskmelons exposed to VOCs from T. asperellum T76-14 showed no fruit rot after incubation at seven days compared to fruit rot in the control. This study demonstrated the ability of T. asperellum T76-14 to produce volatile antifungal compounds, showing that it can be a major mechanism involved in and responsible for the successful inhibition of F. incarnatum and control of postharvest fruit rot in muskmelons.

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Bioactivity of volatile organic compounds by Aureobasidium species against gray mold of tomato and table grape

World Journal of Microbiology and Biotechnology ◽

10.1007/s11274-020-02947-7 ◽

2020 ◽

Vol 36 (11) ◽

Author(s):

A. Di Francesco ◽

J. Zajc ◽

N. Gunde-Cimerman ◽

E. Aprea ◽

F. Gasperi ◽

...

Keyword(s):

Volatile Organic Compounds ◽

Organic Compounds ◽

Mycelial Growth ◽

Solid Phase ◽

Table Grape ◽

Conidial Suspension ◽

Vitro Assay ◽

Volatile Organic

Abstract Aureobasidium strains isolated from diverse unconventional environments belonging to the species A. pullulans, A. melanogenum, and A. subglaciale were evaluated for Volatile Organic Compounds (VOCs) production as a part of their modes of action against Botrytis cinerea of tomato and table grape. By in vitro assay, VOCs generated by the antagonists belonging to the species A. subglaciale showed the highest inhibition percentage of the pathogen mycelial growth (65.4%). In vivo tests were conducted with tomatoes and grapes artificially inoculated with B. cinerea conidial suspension, and exposed to VOCs emitted by the most efficient antagonists of each species (AP1, AM10, AS14) showing that VOCs of AP1 (A. pullulans) reduced the incidence by 67%, partially confirmed by the in vitro results. Conversely, on table grape, VOCs produced by all the strains did not control the fungal incidence but were only reducing the infection severity (< 44.4% by A. pullulans; < 30.5% by A. melanogenum, and A. subglaciale). Solid-phase microextraction (SPME) and subsequent gas chromatography coupled to mass spectrometry identified ethanol, 3-methyl-1-butanol, 2-methyl-1-propanol as the most produced VOCs. However, there were differences in the amounts of produced VOCs as well as in their repertoire. The EC50 values of VOCs for reduction of mycelial growth of B. cinerea uncovered 3-methyl-1-butanol as the most effective compound. The study demonstrated that the production and the efficacy of VOCs by Aureobasidium could be directly related to the specific species and pathosystem and uncovers new possibilities for searching more efficient VOCs producing strains in unconventional habitats other than plants.

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Current Challenges in Volatile Organic Compounds Analysis as Potential Biomarkers of Cancer

Journal of Biomarkers ◽

10.1155/2015/981458 ◽

2015 ◽

Vol 2015 ◽

pp. 1-16 ◽

Cited By ~ 60

Author(s):

Kamila Schmidt ◽

Ian Podmore

Keyword(s):

Volatile Organic Compounds ◽

Organic Compounds ◽

Clinical Symptoms ◽

Ex Vivo ◽

Critical Evaluation ◽

Detection Techniques ◽

Volatile Organic ◽

Potential Biomarkers

An early diagnosis and appropriate treatment are crucial in reducing mortality among people suffering from cancer. There is a lack of characteristic early clinical symptoms in most forms of cancer, which highlights the importance of investigating new methods for its early detection. One of the most promising methods is the analysis of volatile organic compounds (VOCs). VOCs are a diverse group of carbon-based chemicals that are present in exhaled breath and biofluids and may be collected from the headspace of these matrices. Different patterns of VOCs have been correlated with various diseases, cancer among them. Studies have also shown that cancer cells in vitro produce or consume specific VOCs that can serve as potential biomarkers that differentiate them from noncancerous cells. This review identifies the current challenges in the investigation of VOCs as potential cancer biomarkers, by the critical evaluation of available matrices for the in vivo and in vitro approaches in this field and by comparison of the main extraction and detection techniques that have been applied to date in this area of study. It also summarises complementary in vivo, ex vivo, and in vitro studies conducted to date in order to try to identify volatile biomarkers of cancer.

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Comparison of in vivo derived and scaled in vitro metabolic rate constants for several volatile organic compounds (VOCs)

Toxicology in Vitro ◽

10.1016/j.tiv.2020.105002 ◽

2020 ◽

Vol 69 ◽

pp. 105002

Author(s):

Elaina M. Kenyon ◽

Christopher Eklund ◽

Rex A. Pegram ◽

John C. Lipscomb

Keyword(s):

Volatile Organic Compounds ◽

Metabolic Rate ◽

Organic Compounds ◽

Rate Constants ◽

Volatile Organic

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In vitro and in silico approach of fungal growth inhibition by Trichoderma asperellum HbGT6-07 derived volatile organic compounds

Arabian Journal of Chemistry ◽

10.1016/j.arabjc.2021.103290 ◽

2021 ◽

pp. 103290

Author(s):

Md. Kamaruzzaman ◽

Md. Samiul Islam ◽

Shafi Mahmud ◽

Shakil Ahmed Polash ◽

Razia Sultana ◽

...

Keyword(s):

Volatile Organic Compounds ◽

Growth Inhibition ◽

Organic Compounds ◽

In Silico ◽

Fungal Growth ◽

Trichoderma Asperellum ◽

Volatile Organic ◽

Fungal Growth Inhibition

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Corrigendum to ’Comparison of In Vivo Derived and Scaled In Vitro Metabolic Rate Constants for Several Volatile Organic Compounds (VOCs)’ [toxicology in vitro 68 (2020) start page–end page]

Toxicology in Vitro ◽

10.1016/j.tiv.2020.105045 ◽

2020 ◽

pp. 105045

Author(s):

Elaina M. Kenyon ◽

Christopher Eklund ◽

Rex A. Pegram ◽

John C. Lipscomb

Keyword(s):

Volatile Organic Compounds ◽

Metabolic Rate ◽

Organic Compounds ◽

Rate Constants ◽

Volatile Organic

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Identification of Rhizospheric Actinomycete Streptomyces lavendulae SPS-33 and the Inhibitory Effect of its Volatile Organic Compounds against Ceratocystis fimbriata in Postharvest Sweet Potato (Ipomoea batatas (L.) Lam.)

Microorganisms ◽

10.3390/microorganisms8030319 ◽

2020 ◽

Vol 8 (3) ◽

pp. 319 ◽

Cited By ~ 4

Author(s):

Xuewei Li ◽

Beibei Li ◽

Shurui Cai ◽

Yu Zhang ◽

Mingjie Xu ◽

...

Keyword(s):

Volatile Organic Compounds ◽

Sweet Potato ◽

Organic Compounds ◽

Morphological Identification ◽

Postharvest Storage ◽

Ceratocystis Fimbriata ◽

Streptomyces Lavendulae ◽

Volatile Organic

Black spot disease, which is caused by the pathogenic fungal Ceratocystis fimbriata, seriously affects the production of sweet potato and its quality during postharvest storage. In this study, the preliminary identification of the rhizosphere actinomycete strain SPS-33, and its antifungal activity of volatiles in vitro and in vivo was investigated. Based on morphological identification and phylogenetic analysis of the 16S rRNA gene sequence, strain SPS-33 was identified as Streptomyces lavendulae. Volatile organic compounds (VOCs) emitted by SPS-33 inhibited mycelial growth and sporulation of C. fimbriata in vitro and also induced a series of observable hyphae morphological changes. In an in vivo pathogenicity assay, exposure to SPS-33 significantly decreased the lesion diameter and water loss rate in sweet potato tuberous roots (TRs) inoculated with C. fimbriata. It increased the antioxidant enzymes’ activities of peroxidase, catalase, and superoxide dismutase as well as decreased malondialdehyde and increased total soluble sugar. In the VOC profile of SPS-33 detected by a headspace solid-phase micro extraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS), heptadecane, tetradecane, and 3-methyl-1-butanol were the most abundant compounds. 2-Methyl-1-butanol, 3-methyl-1-butanol, pyridine, and phenylethyl alcohol showed strong antifungal effects against C. fimbriata. These findings suggest that VOCs from S. lavendulae SPS-33 have the potential for pathogen C. fimbriata control in sweet potato postharvest storage by fumigant action.

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