Yolk-Shell Hierarchical Pore Au@MOF Nanostructures: Efficient Gas Capture and Enrichment for Advanced Breath Analysis.

Surface-enhanced Raman scattering (SERS) offers a promising, cost-effective alternative for the rapid, sensitive, and quantitative analysis of potential biomarkers in exhaled gases, which is crucial for early disease diagnosis. However, a major challenge in SERS is the effective detection of gaseous analytes, primarily due to difficulties in enriching and capturing them within the substrate's "hotspot" regions. This study introduces an advanced gas sensor combining mesoporous gold (MesoAu) and metal-organic frameworks (MOFs), exhibiting high sensitivity and rapid detection capabilities. The MesoAu provides abundant active sites and interconnected mesopores, facilitating the diffusion of analytes for detection. A ZIF-8 shell enveloping MesoAu further enriches target molecules, significantly enhancing sensitivity. A proof-of-concept experiment demonstrated a detection limit of 0.32 ppb for gaseous benzaldehyde, indicating promising prospects for the rapid diagnosis of early stage lung cancer. This research also pioneers a novel approach for constructing hierarchical plasmonic nanostructures with immense potential in gas sensing.

Enhanced Sensitivity in Photovoltaic 2D MoS2/Te Heterojunction VOC Sensors.

Volatile organic compound (VOC) sensors have a broad range of applications including healthcare monitoring, product quality control, and air quality management. However, many such applications are demanding, requiring sensors with high sensitivity and selectivity. 2D materials are extensively used in many VOC sensing devices due to their large surface-to-volume ratio and fascinating electronic properties. These properties, along with their exceptional flexibility, low power consumption, room-temperature operation, chemical functionalization potential, and defect engineering capabilities, make 2D materials ideal for high-performance VOC sensing. Here, a 2D MoS2/Te heterojunction is reported that significantly improves the VOC detection compared to MoS2 and Te sensors on their own. Density functional theory (DFT) analysis shows that the MoS2/Te heterojunction significantly enhances the adsorption energy and therefore sensing sensitivity of the sensor. The sensor response, which denotes the percentage change in the sensor's conductance upon VOC exposure, is further enhanced under photo-illumination and zero-bias conditions to values up to ≈7000% when exposed to butanone. The MoS2/Te heterojunction is therefore a promising device architecture for portable and wearable sensing applications.

Green leaf volatiles co-opt proteins involved in molecular pattern signalling in plant cells.

The green leaf volatiles (GLVs) Z-3-hexen-1-ol (Z3-HOL) and Z-3-hexenyl acetate (Z3-HAC) are airborne infochemicals released from damaged plant tissues that induce defenses and developmental responses in receiver plants, but little is known about their mechanism of action. We found that Z3-HOL and Z3-HAC induce similar but distinctive physiological and signaling responses in tomato seedlings and cell cultures. In seedlings, Z3-HAC showed a stronger root growth inhibition effect than Z3-HOL. In cell cultures, the two GLVs induced distinct changes in MAP kinase (MAPK) activity and proton fluxes as well as rapid and massive changes in the phosphorylation status of proteins within 5 min. Many of these phosphoproteins are involved in reprogramming the proteome from cellular homoeostasis to stress and include pattern recognition receptors, a receptor-like cytoplasmic kinase, MAPK cascade components, calcium signaling proteins and transcriptional regulators. These are well-known components of damage-associated molecular pattern (DAMP) signaling pathways. These rapid changes in the phosphoproteome may underly the activation of defense and developmental responses to GLVs. Our data provide further evidence that GLVs function like DAMPs and indicate that GLVs coopt DAMP signaling pathways.

High-quality identification of volatile organic compounds (VOCs) originating from breath.

INTRODUCTION: Volatile organic compounds (VOCs) can arise from underlying metabolism and are detectable in exhaled breath, therefore offer a promising route to non-invasive diagnostics. Robust, precise, and repeatable breath measurement platforms able to identify VOCs in breath distinguishable from background contaminants are needed for the confident discovery of breath-based biomarkers. OBJECTIVES: To build a reliable breath collection and analysis method that can produce a comprehensive list of known VOCs in the breath of a heterogeneous human population. METHODS: The analysis cohort consisted of 90 pairs of breath and background samples collected from a heterogenous population. Owlstone Medical's Breath Biopsy® OMNI® platform, consisting of sample collection, TD-GC-MS analysis and feature extraction was utilized. VOCs were determined to be "on-breath" if they met at least one of three pre-defined metrics compared to paired background samples. On-breath VOCs were identified via comparison against purified chemical standards, using retention indexing and high-resolution accurate mass spectral matching. RESULTS: 1471 VOCs were present in > 80% of samples (breath and background), and 585 were on-breath by at least one metric. Of these, 148 have been identified covering a broad range of chemical classes. CONCLUSIONS: A robust breath collection and relative-quantitative analysis method has been developed, producing a list of 148 on-breath VOCs, identified using purified chemical standards in a heterogenous population. Providing confirmed VOC identities that are genuinely breath-borne will facilitate future biomarker discovery and subsequent biomarker validation in clinical studies. Additionally, this list of VOCs can be used to facilitate cross-study data comparisons for improved standardization.

Bispidine Based Hg(II) 1D Coordination Polymers of Helical Topology: Stability, Selective Adsorption and 1D to 2D Dimensionality Change Via SC-to-SC Transformation.

Bispidine based Hg(II) coordination polymers of helical topology CP-MeOH and CP-EtOH are almost isostructural (they mainly differ for the solvent included in their lattice and by a small % in unit cell parameters) but they differ for everything else: i) their intrinsic stability, ii) their ability to adsorb solvents upon prior evacuation, iii) their accessible structural transformations. In particular, one of the two starting materials, once evacuated, is capable to adsorb methanol from atmospheres containing binary and ternary mixtures of volatile organic compounds (MeOH, CHCl3 and EtOH) under ambient conditions (25 °C, 1 atm) and with a marked selectivity. The other one is not, but undergoes a 1D to 2D dimensionality change which can be monitored in situ by SC-XRD through a SC-to-SC process.

Quantification for photochemical loss of volatile organic compounds upon ozone formation chemistry at an industrial city (Zibo) in North China Plain.

Volatile organic compounds (VOCs) are consumed by photochemical reactions during transport, leading to inaccuracies in estimating the local ozone (O3) formation mechanism and its subsequent strategy for O3 attainment. To comprehensively quantify the deviations in O3 formation mechanism by consumed VOCs (C-VOCs), a 5-month field campaign was conducted in a typical industrial city in Northern China over incorporating a 0-D box model (implemented with MCMv3.3.1). The averaged C-VOCs concentration was 6.8 ppbv during entire period, and Alkenes accounted for 62% dominantly. Without considering C-VOCs, the relative incremental reactivity (RIR) of anthropogenic VOCs (AVOC, overestimated by 68%-75%) and NOx (underestimated by 137%-527%) demonstrated deviations at multiple scenarios, and the RIR deviations for precursors in High-O3-periods (HOP) were lower than Low-O3-periods (LOP). The RIR deviations from individual species involved C-VOCs calculation did not impact the identification for the high-ranking-RIR AVOC species but non-negligible. Monthly comparisons showed that higher C-VOCs concentrations would lead to higher RIR deviations. The daily maximum of net Ox production rate (P(Ox)) and the regional transport Ox (Trans(Ox)) without C-VOCs were underestimated by 56%-194% and 81%-243%, respectively. After considering C-VOCs, the contribution of HO2+NO for Ox gross production (G(Ox)) decreased by 7% (LOP) and 7% (HOP), but OH + NO2 for Ox destruction (D(Ox)) decreased by 16% (LOP) and 23% (HOP), and alkenes + O3 increased for D(Ox) by 12% (LOP) and 22% (HOP). This implies that VOCs-NOx-O3 sensitivity was deviated between with/without C-VOCs, and severe O3 pollution rendered deviations in O3 formation, especially via NOx-driving chemistry. Based on RIR(NOx)/RIR(AVOC) with/without C-VOCs, the sensitivity regime shifted from VOCs-limited (-0.93) to transition (1.38) at LOP, and from VOCs-limited (0.19) to NOx-limited (3.79) at HOP. Our results reflected that the NOx limitation degree was underestimated without constraint C-VOCs, especially HOP, and provided implication to more precise O3 pollution control strategies.

Microbiota diversity of three Brazilian native fishes during ice and frozen storage.

This study aimed to assess the bacterial microbiota involved in the spoilage of pacu (Piaractus mesopotamics), patinga (female Piaractus mesopotamics x male Piaractus brachypomus), and tambacu (female Colossoma macropomum × male Piaractus mesopotamics) during ice and frozen storage. Changes in the microbiota of three fish species (N = 22) during storage were studied through 16S rRNA amplicon-based sequencing and correlated with volatile organic compounds (VOCs) and metabolites assessed by nuclear magnetic resonance (NMR). Storage conditions (time and temperature) affected the microbiota diversity in all fish samples. Fish microbiota comprised mainly of Pseudomonas sp., Brochothrix sp., Acinetobacter sp., Bacillus sp., Lactiplantibacillus sp., Kocuria sp., and Enterococcus sp. The relative abundance of Kocuria, P. fragi, L. plantarum, Enterococcus, and Acinetobacter was positively correlated with the metabolic pathways of ether lipid metabolism while B. thermosphacta and P. fragi were correlated with metabolic pathways involved in amino acid metabolism. P. fragi was the most prevalent spoilage bacteria in both storage conditions (ice and frozen), followed by B. thermosphacta. Moreover, the relative abundance of identified Bacillus strains in fish samples stored in ice was positively correlated with the production of VOCs (1-hexanol, nonanal, octenol, and 2-ethyl-1-hexanol) associated with off-flavors. 1H NMR analysis confirmed that amino acids, acetic acid, and ATP degradation products increase over (ice) storage, and therefore considered chemical spoilage index of fish fillets.

Evaluation of highly adsorptive Guefoams (multifunctional guest-containing foams) as a potential sorbent for determination of volatile organic compounds (VOCs) by means of thermal desorption.

The present work delves into the feasibility of employing a novel structured sorbent referred to as GFAD (Guefoam Adsorption Device) for the determination of volatile organic compounds (VOCs) in liquid samples. The chosen method has been static headspace sorptive extraction-thermal desorption gas chromatography mass spectrometry (HSSE-TD-GC-MS). The GFAD comprises an aluminum cellular material with a distinct replication structure and a solid guest phase consisting of activated carbon particles dispersed within the cavities of the cellular aluminum. The extensive specific surface area, robustness, and exceptional thermal conductivity of this pioneering material offer distinct advantages over commercially available polydimethylsiloxane-based Twister® devices. Therefore, the trapping efficiency for volatile organic compounds is enhanced, and it is possible to perform the analysis of concentrated samples. According to computational simulations, it has been demonstrated that GFAD has a high heat conductivity. As a result, the desorption efficiency is improved, and minimal temperature gradients are generated throughout the GFAD during the heating process. Besides, the energy consumption is significantly lowered, thus aligning with environmentally conscientious and sustainable analytical practices.The experimental results give a proof of the suitability of the GFAD for determining gaseous compounds in liquid samples through HSSE-TD-GC-MS. For volatile species, the new material provides higher peak areas and lower limits of detection than a commercially available Twister® device. Furthermore, the GFAD is reusable, its adsorbing properties remaining unchanged during, at least, 100 consecutive analyses. In addition, unlike to the Twister®, no intense siloxane peaks are observed in the chromatograms obtained with the GFAD. The feasibility of qualitative and semi-quantitative analysis with the new accessory has been demonstrated with both standards and a cereal bioethanol real sample.

Recent Advances and Future Perspectives in the E-Nose Technologies Addressed to the Wine Industry.

Electronic nose devices stand out as pioneering innovations in contemporary technological research, addressing the arduous challenge of replicating the complex sense of smell found in humans. Currently, sensor instruments find application in a variety of fields, including environmental, (bio)medical, food, pharmaceutical, and materials production. Particularly the latter, has seen a significant increase in the adoption of technological tools to assess food quality, gradually supplanting human panelists and thus reshaping the entire quality control paradigm in the sector. This process is happening even more rapidly in the world of wine, where olfactory sensory analysis has always played a central role in attributing certain qualities to a wine. In this review, conducted using sources such as PubMed, Science Direct, and Web of Science, we examined papers published between January 2015 and January 2024. The aim was to explore prevailing trends in the use of human panels and sensory tools (such as the E-nose) in the wine industry. The focus was on the evaluation of wine quality attributes by paying specific attention to geographical origin, sensory defects, and monitoring of production trends. Analyzed results show that the application of E-nose-type sensors performs satisfactorily in that trajectory. Nevertheless, the integration of this type of analysis with more classical methods, such as the trained sensory panel test and with the application of destructive instrument volatile compound (VOC) detection (e.g., gas chromatography), still seems necessary to better explore and investigate the aromatic characteristics of wines.

Physical Trace Gas Identification with the Photo Electron Ionization Spectrometer (PEIS).

Chemosensor technology for trace gases in the air always aims to identify these compounds and then measure their concentrations. For identification, traceable methods are sparse and relate to large appliances such as mass spectrometers. We present a new method that uses the alternative traceable measurement of the ionization energies of trace gases in a way that can be miniaturized and energetically tuned. We investigate the achievable performance. Since tunable UV sources are not available for photoionization, we take a detour via impact ionization with electrons, which we generate using the photoelectric effect and bring to sharp, defined energies on a nanoscale in the air. Electron impact ionization is thus possible at air pressures of up to 900 hPa. The sensitivity of the process reaches 1 ppm and is equivalent to that of classic PID. With sharpened energy settings, substance identification is currently possible with an accuracy of 30 meV. We can largely explain the experimental observations with the known quantum mechanical models.

Ambient Monitoring Portable Sensor Node for Robot-Based Applications.

The leakage of gases and chemical vapors is a common accident in laboratory processes that requires a rapid response to avoid harmful effects if humans and instruments are exposed to this leakage. In this paper, the performance of a portable sensor node designed for integration with mobile and stationary robots used to transport chemical samples in automated laboratories was tested and evaluated. The sensor node has four main layers for executing several functions, such as power management, control and data preprocessing, sensing gases and environmental parameters, and communication and data transmission. The responses of three metal oxide semiconductor sensors, BME680, ENS160, and SGP41, integrated into the sensing layer have been recorded for various volumes of selected chemicals and volatile organic compounds, including ammonia, pentane, tetrahydrofuran, butanol, phenol, xylene, benzene, ethanol, methanol, acetone, toluene, and isopropanol. For mobile applications, the sensor node was attached to a sample holder on a mobile robot (ASTI ProBOT L). In addition, the sensor nodes were positioned close to automation systems, including stationary robots. The experimental results revealed that the tested sensors have a different response to the tested volumes and can be used efficiently for hazardous gas leakage detection and monitoring.

Volatile Organic Compounds (VOCs) Produced by Levilactobacillus brevis WLP672 Fermentation in Defined Media Supplemented with Different Amino Acids.

Fermentation by lactic acid bacteria (LAB) is a promising approach to meet the increasing demand for meat or dairy plant-based analogues with realistic flavours. However, a detailed understanding of the impact of the substrate, fermentation conditions, and bacterial strains on the volatile organic compounds (VOCs) produced during fermentation is lacking. As a first step, the current study used a defined medium (DM) supplemented with the amino acids L-leucine (Leu), L-isoleucine (Ile), L-phenylalanine (Phe), L-threonine (Thr), L-methionine (Met), or L-glutamic acid (Glu) separately or combined to determine their impact on the VOCs produced by Levilactobacillus brevis WLP672 (LB672). VOCs were measured using headspace solid-phase microextraction (HS-SPME) gas chromatography-mass spectrometry (GC-MS). VOCs associated with the specific amino acids added included: benzaldehyde, phenylethyl alcohol, and benzyl alcohol with added Phe; methanethiol, methional, and dimethyl disulphide with added Met; 3-methyl butanol with added Leu; and 2-methyl butanol with added Ile. This research demonstrated that fermentation by LB672 of a DM supplemented with different amino acids separately or combined resulted in the formation of a range of dairy- and meat-related VOCs and provides information on how plant-based fermentations could be manipulated to generate desirable flavours.

The effect of terroir on volatilome fingerprinting and qualitative attributes of non-irrigated grapes reveals differences on glycosylated aroma compounds.

BACKGROUND: 'Xynisteri' is considered as the reference white grape cultivar in Cyprus with remarkable adaptation to adverse edaphoclimatic conditions and appreciable oenological properties that renders it as an appropriate cultivar for studies within a global context due to climate change. To this aim, two distinct non-irrigated plots with different climatic conditions, soil properties and levels of rainfall were selected; Koilani [KO, altitude 800 m, 76% calcium carbonate (CaCO3) content, pH 7.97, average temperature: 16.5 °C, rainfall: 229 mm] and Kyperounda (KY, altitude 1200 m, CaCO3-free soil, pH 6.47, average temperature: 14.9 °C, rainfall: 658 mm). An array of physiological, biochemical and qualitative indices during successive developmental stages (BBCH 75-89) were determined. During the advanced on-vine developmental stages (BBCH 85-89), the aromatic profile of grapes was assessed with the employment of gas chromatography-mass spectrometry (GC-MS). Such analysis was complemented with non-destructive chemometric analyses. RESULTS: Berry ripening process substantially differed on the examined plots; BBCH 89 stage reached at 267 and 303 Julian days for KO and KY, respectively. Results indicated that berry weight, soluble solids content (SSC) and α-amino nitrogen were higher in KO than in KY, with exception made for ammonium nitrogen content. A total of 75 compounds, including aliphatic alcohols, benzenic compounds, phenols, vanillins, monoterpenes and C13-norisoprenoids were identified and quantified. The variations of mesoclimatic conditions affected the volatile organic compound (VOC) profiles at the fully-ripe stage, showing a considerable rise in glycosylated aroma compounds, especially monoterpenes and benzenic compounds. In particular, the higher amount of glycosylated aroma compounds were obtained in KY berries up to mid-ripe, whereas KO showed higher glycosylated aroma compounds at fully-ripe stage. Results reported herein indicate that aroma profile of 'Xynisteri' grapes varied substantially in the examined terroirs. Interestingly, the limited rainfall in KΟ non-irrigated vine did not compromise qualitative and aromatic properties of berries. CONCLUSIONS: The present study aimed at dissecting the impact of terroir on bush-trained, non-irrigated grapevines of a cultivar appropriate for extreme climate change scenarios. The volatilome fingerprint was highly variable among the examined plots; such results can be further exploited at vinification level towards production of single vineyard premium end products. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Evaluating workplace protection factors (WPFs) of different firefighter PPE interface control measures for select volatile organic compounds (VOCs).

Structural firefighters are exposed to a complex set of contaminants and combustion byproducts, including volatile organic compounds (VOCs). Additionally, recent studies have found structural firefighters' skin may be exposed to multiple chemical compounds via permeation or penetration of chemical byproducts through or around personal protective equipment (PPE). This mannequin-based study evaluated the effectiveness of four different PPE conditions with varying contamination control measures (incorporating PPE interface design features and particulate blocking materials) to protect against ingress of several VOCs in a smoke exposure chamber. We also investigated the effectiveness of long-sleeve base layer clothing to provide additional protection against skin contamination. Outside gear air concentrations were measured from within the smoke exposure chamber at the breathing zone, abdomen, and thigh heights. Personal air concentrations were collected from mannequins under PPE at the same general heights and under the base layer at abdomen and thigh heights. Sampled contaminants included benzene, toluene, styrene, and naphthalene. Results suggest that VOCs can readily penetrate the ensembles. Workplace protection factors (WPFs) were near one for benzene and toluene and increased with increasing molecular weight of the contaminants. WPFs were generally lower under hoods and jackets compared to under pants. For all PPE conditions, the pants appeared to provide the greatest overall protection against ingress of VOCs, but this may be due in part to the lower air concentrations toward the floor (and cuffs of pants) relative to the thigh-height outside gear concentrations used in calculating the WPFs. Providing added interface control measures and adding particulate-blocking materials appeared to provide a protective benefit against less-volatile chemicals, like naphthalene and styrene.

Appropriate control measure design by rapidly identifying risk areas of volatile organic compounds during the remediation excavation at an organic contaminated site.

Many organic contaminated sites require on-site remediation; excavation remediation processes can release many volatile organic compounds (VOCs) which are key atmospheric pollutants. It is therefore important to rapidly identify VOCs during excavation and map their risk areas for human health protection. In this study, we developed a rapid analysis and assessment method, aiming to and reveal the real-time distribution of VOCs, evaluate their human health risks by quantitative models, and design appropriate control measures. Through on-site diagonal distribution sampling and analysis, VOCs concentration showed a decreasing trend within 5 m from the excavation point and then increased after 5 m with the increase in distance from the excavation point (p < 0.05). The concentrations of VOCs near the dominant wind direction were higher than the concentrations of surrounding pollutants. In contrast with conventional solid-phase adsorption (SPA) and thermal desorption gas chromatography-mass spectrometry (TD-GC/MS) methods for determining the composition and concentration of VOCs, the rapid measurement of VOCs by photo-ionization detector (PID) fitted well with the chemical analysis and modeling assessment of cancer/non-cancer risk. The targeting area was assessed as mild-risk (PID < 10 ppm), moderate-risk (PID from 10 to 40 ppm), and heavy-risk (PID > 40 ppm) areas. Similarly, the human health risks also decreased gradually with the distance from the excavation point, with the main risk area located in the dominant wind direction. The results of rapid PID assessment were comparable to conventional risk evaluation, demonstrating its feasibility in rapidly identifying VOCs releases and assessing the human health risks. This study also suggested appropriate control measures that are important guidance for personal protection during the remediation excavation process.

Characteristics and Source Apportionment of Volatile Organic Compounds in a Coastal Industrial Area: A Case Study in the Yangtze River Delta of China.

In recent years, the coastal area in East China has experienced elevated volatile organic compounds (VOCs) levels during specific periods. VOCs have become one of the major atmospheric pollutants in these areas. In this study, 64 compounds including alkanes, alkenes, halohydrocarbons, aromatics, and oxygenated VOCs (OVOCs) were obtained by the TO-15 method through a 12-month campaign in industrial, urban and suburban areas in the Yangtze River Delta of China. The overall trends of total VOC (TVOC) concentrations at eight sampling sites were as follows: winter > autumn > spring > summer. The proportion of VOC categories was various at industrial sites, while OVOCs and halohydrocarbons had high proportions at urban sites and suburban sites, respectively. Coating, vehicle emission, petrochemical source, industrial source, and gasoline volatilization were identified as the major VOC emission sources by the positive matrix factorization model. Petrochemical and coating sources were the prime VOC sources at industrial sites. Aromatics contributed the most ozone formation potential at industrial sites, while OVOCs provided the main contributions at both urban and suburban sites during four seasons. According to the health risk assessment, a high probability of non-carcinogenic risk existed at three industrial sites. Special attention should be given to certain VOCs, such as acrolein and 1,2-dibromoethane in industrial areas.

Characteristics and source apportionment of ambient volatile organic compounds and ozone generation sensitivity in urban Jiaozuo, China.

In recent years, many cities have taken measures to reduce volatile organic compounds (VOCs), an important precursor of ozone (O3), to alleviate O3 pollution in China. 116 VOC species were measured by online and offline methods in the urban area of Jiaozuo from May to October in 2021 to analyze the compositional characteristics. VOC sources were analyzed by a positive matrix factorization (PMF) model, and the sensitivity of ozone generation was determined by ozone isopleth plotting research (OZIPR) simulation. The results showed that the average volume concentration of total VOCs was 30.54 ppbv and showed a bimodal feature due to the rush-hour traffic in the morning and at nightfall. The most dominant VOC groups were oxygenated VOCs (OVOCs, 29.3%) and alkanes (26.7%), and the most abundant VOC species were acetone and acetylene. However, based on the maximum incremental reactivity (MIR) method, the major VOC groups in terms of ozone formation potential (OFP) contribution were OVOCs (68.09 µg/m3, 31.5%), aromatics (62.90 µg/m3, 29.1%) and alkene/alkynes (54.90 µg/m3, 25.4%). This indicates that the control of OVOCs, aromatics and alkene/alkynes should take priority. Five sources of VOCs were quantified by PMF, including fixed sources of fossil fuel combustion (27.8%), industrial processes (25.9%), vehicle exhaust (19.7%), natural and secondary formation (13.9%) and solvent usage (12.7%). The empirical kinetic modeling approach (EKMA) curve obtained by OZIPR on O3 exceedance days indicated that the O3 sensitivity varied in different months. The results provide theoretical support for O3 pollution prevention and control in Jiaozuo.

Formation mechanism of glandular trichomes involved in the synthesis and storage of terpenoids in lavender.

BACKGROUND: Lavender (genus Lavandula, family Lamiaceae) is an aromatic plant widely grown as an ornamental plant. The chemical composition of lavender is characterized by monoterpenoids, sesquiterpenoids, and other compounds, which are primarily synthesized and stored in epidermal secretory structures called glandular trichomes (GTs). Volatile organic compounds (VOCs) are responsible for the aroma characteristics of plant oil that drive consumer preference. Aroma is usually regarded as a characteristic trait for the classification of aromatic plants. Interestingly, VOCs are synthesized and stored in GTs. Lamiaceae species such as purple perilla, peppermint, basil, thyme, and oregano usually possess two types of GTs: peltate glandular trichomes (PGTs) and capitate glandular trichomes (CGTs). But the development process of PGTs in lavender has been reported in only a few studies to date. RESULTS: In this study, we identified and quantified the VOCs in four lavender cultivars by headspace-solid phase micro extraction-gas chromatography mass spectrometry (HS-SPME-GC-MS). A total of 66 VOCs were identified in these four cultivars, the most prominent of which were linalyl acetate and linalool, and flowers were the main site of accumulation of these VOCs. Here, we examined the developmental process of PGTs, including the formation of their base, body, and apex. The apex cells contained secretory cavities, which produced VOCs. Based on the reference genome sequence of the lavender cultivar 'Jingxun 2', several R2R3-MYB subfamily genes related to GT formation were identified. These results will guide the engineering of GTs and molecular breeding of lavender for improving the VOC content. CONCLUSIONS: In this study, we identified the VOCs in four lavender cultivars. We analyzed the formation of GTs, and compared the number and diameter size of PGTs among four lavender cultivars. Additionally, we identified four candidate genes belonging to the R2R3-MYB family.

Chemical ecology of Himalayan eggplant variety's antixenosis: identification of geraniol as an oviposition deterrent against the eggplant shoot and fruit borer.

Eggplant (Solanum melongena) suffers severe losses due to a multi-insecticide-resistant lepidopteran pest, shoot and fruit borer (SFB, Leucinodes orbonalis). Heavy and combinatorial application of pesticides for SFB control renders eggplant risky for human consumption. We observed that gravid SFB females do not oviposit on Himalayan eggplant variety RC-RL-22 (RL22). We hypothesized that RL22 contained an antixenosis factor. Females' behavior indicated that the RL22 cue they perceived was olfactory. To identify it, leaf volatile blends of seven eggplant varieties were profiled using solid phase microextraction and gas chromatography mass spectrometry. Seven RL22-specific compounds were detected in the plant headspace. In choice assays, oviposition deterrence efficacies of these candidate compounds were independently tested by their foliar application on SFB-susceptible varieties. Complementation of geraniol, which was exclusively found in RL22, reduced oviposition (> 90%). To validate geraniol's role in RL22's SFB-deterrence, we characterized RL22's geraniol synthase and silenced its gene in planta, using virus-induced gene silencing. Geraniol biosynthesis suppression rendered RL22 SFB-susceptible; foliar geraniol application on the geraniol synthase-silenced plants restored oviposition deterrence. We infer that geraniol is RL22's SFB oviposition deterrent. The use of natural compounds like geraniol, which influence the chemical ecology of oviposition, can reduce the load of hazardous synthetic larvicides.

Arbuscular mycorrhizal fungus changes alfalfa (Medicago sativa) metabolites in response to leaf spot (Phoma medicaginis) infection, with subsequent effects on pea aphid (Acyrthosiphon pisum) behavior.

Plant disease occurs simultaneously with insect attack. Arbuscular mycorrhizal fungi (AMF) modify plant biotic stress response. Arbuscular mycorrhizal fungi and pathogens may modify plant volatile organic compound (VOC) production and insect behavior. Nevertheless, such effects are rarely studied, particularly for mesocosms where component organisms interact with each other. Plant-mediated effects of leaf pathogen (Phoma medicaginis) infection on aphid (Acyrthosiphon pisum) infestation, and role of AMF (Rhizophagus intraradices) in modifying these interactions were elucidated in a glasshouse experiment. We evaluated alfalfa disease occurrence, photosynthesis, phytohormones, trypsin inhibitor (TI) and total phenol response to pathogen and aphid attack, with or without AMF, and aphid behavior towards VOCs from AMF inoculated and non-mycorrhizal alfalfa, with or without pathogen infection. AM fungus enhanced alfalfa resistance to pathogen and aphid infestation. Plant biomass, root : shoot ratio, net photosynthetic rate, transpiration rate, stomatal conductance, salicylic acid, and TI were significantly increased in AM-inoculated alfalfa. Arbuscular mycorrhizal fungi and pathogen significantly changed alfalfa VOCs. Aphids preferred VOCs of AM-inoculated and nonpathogen-infected to nonmycorrhizal and pathogen-infected alfalfa. We propose that AMF alter plant response to multiple biotic stresses in ways both beneficial and harmful to the plant host, providing a basis for strategies to manage pathogens and herbivore pests.