Fungal Volatile Compounds Research Articles

Pollination ecology of Dracula erythrochaete (Orchidaceae): brood-site imitation or food deception?

Abstract Pleurothallidinae is the most diverse Neotropical subtribe in Orchidaceae and is almost exclusively pollinated by insects of the order Diptera. Dracula, a genus of 138 species in the Pleurothallidinae, is known to attract Zygothrica (Drosophilidae) flies, common macrofungi visitors, by imitating fungal volatile compounds and lamellae. Interestingly, Dracula orchids do not appear to offer any rewards to their floral visitors. While brood-site imitation of macrofungi has been suggested as their pollination system, the exact behaviour of flies during their extended visits to the orchid flowers has yet to be confirmed. In this study, we document the pollination mechanism of Dracula erythrochaete. We characterize the floral structures involved in the mechanism using anatomical and morphological evidence. Additionally, through in situ observations and camera recordings, we describe the insect behaviour. We show that flowers of D. erythrochaete share the same group of visitors as nearby macrofungi, including different Zygothrica species, seven of which were determined as effective pollinators. Male and female flies were attracted to the flowers and displayed feeding behaviour. Accordingly, proteins were detected in high concentrations on the papillae at the base of the movable lip and in papillary trichomes of the sepals, near the column. The concept of brood-site imitation is debated, as no oviposition events were observed and no eggs were found on the flowers. Therefore, a mixed strategy of congregation/brood-site imitation and food reward is proposed for pollination.

Fungal Community Succession and Volatile Compound Changes during Fermentation of Laobaigan Baijiu from Chinese Hengshui Region.

To investigate the core fungal community succession and its effects of volatile compound production during different stages (D-1, D-2, D-3, E-4, E-5, and E-6) of Hengshui Laobaigan Baijiu, high-throughput sequencing (HTS) was carried out, accompanied by the identification and quantification of the volatile flavor compounds using headspace solid-phase coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS). HTS results demonstrated that the fungal community of stage D-1 was similar to that of E-4 after adding Daqu, while the richness and diversity of the fungal community were most prominent at stage E-6. Moreover, the addition of Daqu at the beginning of Ercha fermentation resulted in a significant increase in the relative abundances of the fungal community at the genus level, setting the stage for the production of volatile compounds. GC-MS analysis revealed the presence of a total of 45 volatile compounds. Combining the GC-MS result with the heat map and principal component analysis (PCA), the concentrations of volatile compounds were highest in stage E-5. Meanwhile, concentrations of esters, especially ethyl acetate, ethyl lactate, isoamyl acetate and ethyl hexanoate, were high in both stages E-5 and E-6. This indicated that stage E-5 was crucial to the fermentation process of Laobaigan Baijiu. Three fungal genera (Saccharomyces, Candida, and Pichia) were indicated as the core microbiota for the production of the main volatile flavor compounds of Laobaigan Baijiu through partial least square (PLS) analysis. The information provided in this study offered valuable insights into the fermentation mechanism of Laobaigan Baijiu, thereby serving as a theoretical framework for enhancing the quality of Baijiu and realizing cost-effective production.

Mitigating the Trade-Off between Growth and Stress Resistance in Plants by Fungal Volatile Compounds.

Plants grow in association with diverse microorganisms. During communication between plants and microbes, beneficial and phytopathogenic bacteria and fungi emit various volatile compounds (VCs). These microbial VCs (mVCs) are typically small, odorous compounds with low boiling point, high vapor pressure, and a lipophilic moiety (Schulz and Dickschat, 2007). Based on recent studies, mVCs appear to regulate plant nutrient acquisition, photosynthesis, phytohormone actions, and metabolic processes, leading to an improvement in plant performance (Fincheira et al., 2021). Since mVCs can activate plant defenses, and/or promote plant growth and development at low concentrations, their application in agriculture is attractive to efficiently grow crops and improve plant health in the absence of excess usage of chemical fertilizers and pesticides. To this end, mVCs have been used for integrated pest management (IPM) to enhance both crop defense and production in field conditions (Brilli et al., 2019). Understanding the molecular action of mVCs in plants will pave the way toward improved crop protection and ecosystem management.

Fungal Community Composition and Its Relationship with Volatile Compounds during Spontaneous Fermentation of Cabernet Sauvignon from Two Chinese Wine-Growing Regions.

The microbial community structure associated with wine in a wine-growing region is shaped by diverse ecological factors within that region, profoundly impacting the wine flavor. In wine fermentation, fungi contribute more sensory-active biochemical compounds than bacteria. In this study, we employed amplicon sequencing to measure samples from the spontaneous fermentation process of cabernet sauvignon wines from two wine-growing regions in China to study the diversity and structural evolution of fungi during spontaneous fermentation and analyze the correlation between fungi and volatile compounds. The results showed significant differences in fungal community structure and diversity in cabernet sauvignon musts from different geographical origins, and these differences affected the flavor quality of the wines. As alcoholic fermentation progressed, Saccharomyces became the dominant fungal genus and reshaped the fungal community structure, and the diversity of the fungal community decreased. However, the fungal communities of each wine-growing region remained distinct throughout the fermentation process. Furthermore, the correlation between the fungal community and volatile compounds indicated that wine is a product of fermentation involving multiple fungal genera, and the flavor is influenced by a variety of fungi. Our study enhances the comprehension of fungal communities in Chinese wine-growing regions, explaining the regulatory role of wine-related fungal microorganisms in wine flavor.

Correlation between fungi and volatile compounds during different fermentation modes at the industrial scale of Merlot wines

Elucidation of the relationship between fungal community development and dynamic changes in volatile components during fermentation is of great significance in controlling wine production. However, such studies on an industrial scale are rarely reported. In this study, fungal community succession during spontaneous fermentation (SPF) and inoculation fermentation (INF) of Merlot wine was monitored by a research strategy combining culture-dependent and culture-independent methods. The volatile compounds were monitored during SPF and INF by headspace solid-phase micro-extraction coupled with gas chromatography-mass spectrometry technology. The Spearman correlation coefficient was also used to investigate the interplay between fungal communities and volatile compounds. We found that fungal community diversity in SPF decreased as fermentation progressed but was significantly higher than that of INF. Starmerella and Kazachstania were the dominant non-Saccharomyces genera in Merlot wine during SPF. However, the presence of commercial yeasts and sulphur dioxide led to a sharp decrease or the disappearance of non-Saccharomyces genera during INF. Spearman correlation analysis revealed that all major volatiles were positively correlated with most functional microbiotas except P. fermentans, S. bacillaris, E. necator, and D. exigua in INF. In SPF, most non-Saccharomyces were negatively correlated with core volatiles, whereas K. humilis, M. laxa, P. kluyveri, and A. japonicus were positively correlated with the major volatiles, especially some higher alcohols (isopentol, heptanol) and terpenes (linalool, citronellol). S. cerevisiae was positively correlated with most of the main volatile substances except ethyl isovalerate and isoamyl acetate. These findings provide a reference for comprehending the diverse fermentation methods employed in the wine industry and improving the quality of Merlot wines.

Volatile Compounds Emitted by Plant Growth-Promoting Fungus Tolypocladium inflatum GT22 Alleviate Copper andPathogen Stress.

Previous studies on the intricate interactions between plants and microorganisms have revealed that fungal volatile compounds (VCs) can affect plant growth and development. However, the precise mechanisms underlying these actions remain to be delineated. In this study, we discovered that VCs from the soilborne fungus Tolypocladium inflatum GT22 enhance the growth of Arabidopsis. Remarkably, priming Arabidopsis with GT22 VCs caused the plant to display an enhanced immune response and mitigated the detrimental effects of both pathogenic infections and copper stress. Transcriptomic analyses of Arabidopsis seedlings treated with GT22 VCs for 3, 24 and 48 h revealed that 90, 83 and 137 genes were differentially expressed, respectively. The responsive genes are known to be involved in growth, hormone regulation, defense mechanisms and signaling pathways. Furthermore, we observed the induction of genes related to innate immunity, hypoxia, salicylic acid biosynthesis and camalexin biosynthesis by GT22 VCs. Among the VCs emitted by GT22, exposure of Arabidopsis seedlings to limonene promoted plant growth and attenuated copper stress. Thus, limonene appears to be a key mediator of the interaction between GT22 and plants. Overall, our findings provide evidence that fungal VCs can promote plant growth and enhance both biotic and abiotic tolerance. As such, our study suggests that exposure of seedlings to T. inflatum GT22 VCs may be a means of improving crop productivity. This study describes a beneficial interaction between T. inflatun GT22 and Arabidopsis. Our investigation of microorganism function in terms of VC activities allowed us to overcome the limitations of traditional microbial application methods. The importance of this study lies in the discovery of T. inflatun GT22 as a beneficial microorganism. This soilborne fungus emits VCs with plant growth-promoting effects and the ability to alleviate both copper and pathogenic stress. Furthermore, our study offers a valuable approach to tracking the activities of fungal VC components via transcriptomic analysis and sheds light on the mechanisms through which VCs promote plant growth and induce resistance. This research significantly advances our knowledge of VC applications and provides an example for further investigations within this field.

Indigenous Saccharomyces cerevisiae Could Better Adapt to the Physicochemical Conditions and Natural Microbial Ecology of Prince Grape Must Compared with Commercial Saccharomyces cerevisiae FX10.

Indigenous Saccharomyces cerevisiae, as a new and useful tool, can be used in fermentation to enhance the aroma characteristic qualities of the wine-production region. In this study, we used indigenous S. cerevisiae L59 and commercial S. cerevisiae FX10 to ferment Prince (a new hybrid variety from Lion Winery) wine, detected the basic physicochemical parameters and the dynamic changes of fungal communities during fermentation, and analyzed the correlations between fungal communities and volatile compounds. The results showed that the indigenous S. cerevisiae L59 could quickly adapt to the specific physicochemical conditions and microbial ecology of the grape must, showing a strong potential for winemaking. Compared with commercial S. cerevisiae FX10, the wine fermented by indigenous S. cerevisiae L59 contained more glycerol and less organic acids, contributing to a rounder taste. The results of volatile compounds indicated that the indigenous S. cerevisiae L59 had a positive effect on adding rosy, honey, pineapple and other sweet aroma characteristics to the wine. Overall, the study we performed showed that selection of indigenous S. cerevisiae from the wine-producing region as a starter for wine fermentation is conducive to improving the aroma profile of wine and preserving the aroma of the grape variety.

Exploring Biocontrol of Unwanted Fungi by Autochthonous Debaryomyces hansenii Strains Isolated from Dry Meat Products.

The exploration of alternatives to the use of chemical preservatives in food is a topic that has attracted great attention. The implementation of regulations associated with the reduction of these elements directly affects the production of cured meat products, with the premise of looking for more “natural” alternatives. From a previously identified collection of 24 strains of Debaryomyces hansenii, isolated from dry meat products of the “Valle de los Pedroches” (Córdoba), a screening was carried out to determine which strains had inhibitory potential against a battery of fungi belonging to the genera Aspergillus, Penicillium, and Candida. After a series of general trials, four strains showing the greatest potential were selected by a streak inhibition assay performed at several concentrations of NaCl. The inhibitory activity of the selected D. hansenii strains was later evaluated by measuring their fungal antagonistic diffusible and volatile compound production following radial inhibition and mouth-to-mouth approaches, respectively. Growth aspects, sporulation, and morphology changes were also considered during these assays. The results support ideas already raised in previous studies, such as the presence of D. hanseniii could imply a reduction of pathogenic fungi in food. Autochthonous yeast strains inhibited not only the mycelial growth, but also sporulation, which strengthens the biocontrol activity of this yeast. Our results show that, under certain conditions, all tested D. hansenii strains were able to alter the growth/development of fungi, being especially evident in the cases of Penicillium expansum and Aspergillus niger. Finally, our research can facilitate the future comparison of results in this area, since we contributed to standardize the methodology described to date, we quantified the number of yeast cells and spores used during the experiments, we homogenized growth conditions for both, yeasts, and molds, and applied an image analyzer software to quantify the growth of the studied microorganisms in solid media.

Relationship between Fungal Communities and Volatile Flavor Components during the Traditional Chinese Fermentation of Capsicum annuum L. Var. Dactylus M

Microbial diversity and dynamic changes play an important role in the production of fermented peppers. In this study, the relationship between fungal communities and the volatile flavor compounds of traditional Chinese fermented peppers was investigated by high-throughput sequencing technology. The results showed that Hanseniaspora was a dominant fungus during the whole fermentation course and accounted for 82.22% of the fungal community on average (ranging from 50.44% to 98.15%). Bidirectional orthogonal partial least squares (O2PLS) analysis between fungal community and volatile flavor compounds showed that Pichia, Hanseniaspora, Cryptococcus, Debarvomvces, and Trichosporon were closely correlated with the concentrations of the volatile flavor components such as α-terpineol, trans-3-tetradecene, 4-methylpentyl 3-methylbutanoate, and 11 other volatile flavor compounds. This study elucidated the dynamics of fungal communities and volatile flavor compounds during pepper fermentation and the correlation between them. Our analysis of the relationships between fungal communities and volatile flavor compounds advanced our understanding of the formation mechanism of volatile flavor compounds in fermented peppers.

Complete Genome Sequences of Five Gram-Negative Bacterial Strains Comprising Synthetic Bacterial Consortium "The Great Five" with Antagonistic Activity Against Plant-Pathogenic Pectobacterium spp. and Dickeya spp.

Complete Genome Sequences of Five Gram-Negative Bacterial Strains Comprising Synthetic Bacterial Consortium "The Great Five" with Antagonistic Activity Against Plant-Pathogenic Pectobacterium spp. and Dickeya spp.

Effect of fungal indoor air pollutant 1-octen-3-ol on levels of reactive oxygen species and nitric oxide as well as dehydrogenases activities in drosophila melanogaster males

ABSTRACT Fungal pollution of indoor environments contributes to several allergic symptoms and represents a public health problem. It is well-established that 1-octen-3-ol, also known as mushroom alcohol, is a fungal volatile organic compound (VOC) commonly found in damp indoor spaces and responsible for the typical musty odor. Previously it was reported that exposure to 1-octen-3-ol induced inflammations and disrupted mitochondrial morphology and bioenergetic rate in Drosophila melanogaster. The aim of this study was to examine the influence of 1-octen-3-ol on dehydrogenase activity, apoptotic biomarkers, levels of nitric oxide (NO) and reactive oxygen species (ROS), as well as antioxidant enzymes activities. D. melanogaster flies were exposed to an atmosphere containing 1-octen-3-ol (2.5 or ∞l/L) for 24 hr. Data demonstrated that 1-octen-3-ol decreased dehydrogenases activity and NO levels but increased ROS levels accompanied by stimulation of glutathione-S-transferase (GST) and superoxide dismutase (SOD) activities without altering caspase 3/7 activation. These findings indicate that adverse mitochondrial activity effects following exposure of D. melanogaster to 1-octen-3-ol, a fungal VOC, may be attributed to oxidant stress. The underlying mechanisms involved in adverse consequences of indoor fungal exposure appear to be related to necrotic but not apoptotic mechanisms. The adverse consequences were sex-dependent with males displaying higher sensitivity to 1-octen-3-ol. Based upon on the fact that the fly genome shares nearly 75% of disease-related genes to human exposure to this fungus may explain the adverse human responses to mold especially for males.

The potential correlations between the fungal communities and volatile compounds of traditional dry sausages from Northeast China

The fungal communities and volatile compounds of traditional dry sausages collected from five different regions in Northeast China, including Harbin (HRB), Daqing (DQ), Suihua (SH), Hegang (HG) and Mudanjiang (MDJ) were investigated in this study. The results revealed clear differences among the fungal community structures of the sausages. Aspergillus pseudoglaucus, Debaryomyces hansenii, and Trichosporon asahii were found to be the predominant species in the sausages from HRB, HG, and MDJ, respectively. Candida zeylanoides was the predominant species in the sausage from DQ and SH. Additionally, 88 volatile compounds were identified in all sausages, of which 31 volatile compounds were the most important flavor contributors (odor activity value > 1). Potential correlation analysis revealed that 8 fungi (D. hansenii, C. zeylanoides, T. asahii, A. pseudoglaucus, Aspergillus sydowii, Penicillium expansum, A. alternata, and Alternaria tenuissima) showed significant positive correlations with ≥3 key volatile compounds. Among these fungi, D. hansenii was regarded as a core functional fungus responsible for the formation of the volatile compounds, given its strong connection with the highest number of key volatile compounds. These results provide detailed insight into the fungal communities of traditional dry sausages and a deeper understanding of the contribution of these fungi to sausage flavor.

Fungal community succession and volatile compound dynamics in Harbin dry sausage during fermentation

This study investigated the fungal community succession and volatile compound dynamics of Harbin dry sausage during a twelve-day fermentation using high-throughput internal transcribed spacer amplicon sequencing and headspace solid-phase microextraction gas chromatography-mass spectrometry. Aspergillus pseudoglaucus was found to be the primary species in the sausages during fermentation, whereas Lasiodiplodia theobromae, Alternaria alternata, Aspergillus caesiellus, and Trichosporon asahii were also prevalent. Additionally, a total of 72 volatile compounds were identified in the dry sausages, of which 24 key compounds (odor activity value > 1) dominated flavor development, including 3 aldehydes, 1 ketone, 4 alcohols, 9 esters, 4 alkenes, and 3 other compounds. Furthermore, correlation analysis suggested that most of the core fungi were positively correlated with the key volatile compounds, particularly A. pseudoglaucus, Aspergillus gracilis, Trichosporon caseorum, Debaryomyces hansenii, and T. asahii. Our findings provide novel insights into the fungal ecology and flavor development of Harbin dry sausages.

Toxicological effects of the fungal volatile compound 1-octen-3-ol against the red flour beetle, Tribolium castaneum (Herbst)

Tribolium castaneum (Herbst) is an important pest of stored grain, and benzoquinones secreted by this pest are harmful to humans. T. castaneum has developed strong resistance to fumigants, and an ecofriendly alternative for managing T. castaneum is urgently needed. 1-Octen-3-ol is a major volatile compound present in many mushrooms and fungi. In the current study, the direct toxicity and sublethal and transgenerational effects of 1-octen-3-ol on T. castaneum were investigated. Our results showed that 1-octen-3-ol had strong insecticidal activity against all developmental stages of T. castaneum and repelled T. castaneum adults. 1-Octen-3-ol showed negative effects on the development and reproduction of parental T. castaneum and the subsequent generation: LC30 and LC50 treatments significantly decreased the pupa and adult weights, pupation and emergence rates and fecundity of the parental generation. In addition, LC50 treatment shortened the larval and pupal periods. In the unexposed progeny (F1) of 1-octen-3-ol-exposed parents, decreased survival and pupation rates as well as reduced pupa and adult weights were observed under LC30 and LC50 treatments. In addition, a model food-system experiment showed that 1-octen-3-ol at 98 μL/L exhibited an efficacy of 100% after 7 days of fumigation and completely eliminated T. castaneum offspring. Although a higher concentration of 1-octen-3-ol was needed to achieve an efficacy equal to that of the positive control, dichlorvos (DDVP), 1-octen-3-ol promoted the seedling growth of wheat seeds, suggesting that the concentration used was not only acceptable but also beneficial for wheat seeds. Overall, 1-octen-3-ol seems to be a promising candidate for use as a fumigant and repellent against T. castaneum as well as a seed protectant.

Volatiles from the fungal phytopathogen Penicillium aurantiogriseum modulate root metabolism and architecture through proteome resetting.

Volatile compounds (VCs) emitted by the fungal phytopathogen Penicillium aurantiogriseum promote root growth and developmental changes in Arabidopsis. Here we characterised the metabolic and molecular responses of roots to fungal volatiles. Proteomic analyses revealed that these compounds reduce the levels of aquaporins, the iron carrier IRT1 and apoplastic peroxidases. Fungal VCs also increased the levels of enzymes involved in the production of mevalonate (MVA)-derived isoprenoids, nitrogen assimilation and conversion of methionine to ethylene and cyanide. Consistently, fungal VC-treated roots accumulated high levels of hydrogen peroxide (H2 O2 ), MVA-derived cytokinins, ethylene, cyanide and long-distance nitrogen transport amino acids. qRT-PCR analyses showed that many proteins differentially expressed by fungal VCs are encoded by VC non-responsive genes. Expression patterns of hormone reporters and developmental characterisation of mutants provided evidence for the involvement of cyanide scavenging and enhanced auxin, ethylene, cytokinin and H2 O2 signalling in the root architecture changes promoted by fungal VCs. Our findings show that VCs from P. aurantiogriseum modify root metabolism and architecture, and improve nutrient and water use efficiencies through transcriptionally and non-transcriptionally regulated proteome resetting mechanisms. Some of these mechanisms are subject to long-distance regulation by photosynthesis and differ from those triggered by VCs emitted by beneficial microorganisms.

Roles of Fungal Volatiles from Perspective of Distinct Lifestyles in Filamentous Fungi.

Volatile compounds (VOCs) are not only media for communication within a species but also effective tools for sender to manipulate behavior and physiology of receiver species. Although the influence of VOCs on the interactions among organisms is evident, types of VOCs and specific mechanisms through which VOCs work during such interactions are only beginning to become clear. Here, we review the fungal volatile compounds (FVOCs) and their impacts on different recipient organisms from perspective of distinct lifestyles of the filamentous fungi. Particularly, we discuss the possibility that different lifestyles are intimately associated with an ability to produce a repertoire of FVOCs in fungi. The FVOCs discussed here have been identified and analyzed as relevant signals under a range of experimental settings. However, mechanistic insight into how specific interactions are mediated by such FVOCs at the molecular levels, amidst complex community of microbes and plants, requires further testing. Experimental designs and advanced technologies that attempt to address this question will facilitate our understanding and applications of FVOCs to agriculture and ecosystem management.

Correlation between autochthonous microbial communities and key odorants during the fermentation of red pepper (Capsicum annuum L.)

High-throughput sequencing and gas chromatography-mass spectrometry (GC-MS) were used to investigate changes in bacterial and fungal communities and volatile flavor compounds during a 32-day fermentation process of red pepper (Capsicum annuum L.). Key odorants were identified by olfactometry combined with GC-MS. Sixteen volatile compounds differed significantly after fermentation, including seven odorants. After fermentation, 1-butanol, 3-methyl-, acetate, phenol, 4-ethyl-2-methoxy-, octanoic acid, ethyl ester, styrene and 2-methoxy-4-vinylphenol were the key odorants, producing a flavor described as peppery, fruity, sour, and spicy. The correlation between microorganisms and odorants in the fermentation was studied and 18 odorants significantly correlated with the core microbial communities in the fermented samples. For further analysis, strains of seven genera were isolated and correlation analysis by O2PLS indicated that Aspergillus, Bacillus, Brachybacterium, Microbacterium and Staphylococcus were highly correlated with the flavor formation. These findings would help to understand the fermentation mechanism of fermented red pepper flavor formation.

Agarwood wound locations provide insight into the association between fungal diversity and volatile compounds in Aquilaria sinensis.

The aim of the present study was to investigate the effect of wound location on the fungal communities and volatile distribution of agarwood in Aquilaria sinensis. Two-dimensional gas chromatography with high-resolution time-of-flight mass spectrometry revealed 60 compounds from the NIST library, including 25 sesquiterpenes, seven monoterpenes, two diterpenes, nine aromatics, nine alkanes and eight others. Of five agarwood types, Types IV and II contained the greatest number and concentration of sesquiterpenes, respectively. The fungal communities of the agarwood were dominated by the phylum Ascomycota and were significantly affected by the type of wound tissue. Community richness indices (observed species, Chao1, PD whole tree, ACE indices) indicated that Types I and IV harboured the most and least species-rich fungal communities, and the fungal communities of Types V, I, III and IV/II were dominated by Lasiodiplodia, Hydnellum, Phaeoisaria and Ophiocordyceps species, respectively. Correlations between fungal species and agarwood components revealed that the chemical properties of A. sinensis were associated with fungal diversity. More specifically, the dominant fungal genera of Types V, I and III (Lasiodiplodia, Hydnellum and Phaeoisaria, respectively) were strongly correlated with specific terpenoid compounds. The finding that wound location affects the fungal communities and volatile distribution of agarwood provides insight into the formation of distinct agarwood types.

Ophiostomatoid fungi can emit the bark beetle pheromone verbenone and other semiochemicals in media amended with various pine chemicals and beetle-released compounds

Abstract Fungal volatile compounds can mediate fungal-insect interactions. Whether fungi can emit insect pheromones and how volatile chemicals change in response to chemicals the fungi naturally encounter is poorly understood. We analyzed volatiles emitted by Grosmannia clavigera (symbiont of the mountain pine beetle) and Ophiostoma ips (symbiont of the pine engraver beetle) growing in liquid media amended with compounds that the fungi naturally encounter: (−)-α-pinene, (+)-α-pinene, (−)-trans-verbenol, verbenone, or ipsdienol. Nine volatile compounds were identified among the fungal and amendment treatments. Volatiles qualitatively and quantitatively differed between fungal species and among amendment treatments. The bark beetle anti-aggregation pheromone (−)-verbenone was detected from both fungi growing in (−)-trans-verbenol-amended media. G. clavigera and O. ips can emit beetle pheromones and other beetle semiochemicals, suggesting that ophiostomatoid fungi could contribute to the chemical ecology of bark beetles. However, such contributions could be modulated by the presence of other environmental chemicals.

Endophytic Fungal Volatile Compounds as Solution for Sustainable Agriculture.

Endophytic fungi produce various mixtures of carbon-based compounds, which are known as volatile organic compounds (VOCs). Research regarding the use of VOCs as pesticide substitutes has garnered much attention. This review summarizes the recent knowledge about VOCs regarding their origin and chemical properties and emphasizes their antimicrobial potential against a wide variety of agricultural pathogens. Several studies have highlighted the importance of VOCs as antimicrobial agents. Nevertheless, the application of VOCs in biofumigation methods still requires the advanced evaluation of their phytotoxicity.