Volatile organic compound-mediated conversation in soil

Chemical communication is fundamental in soil ecosystems, with volatile organic compounds (VOCs) playing a crucial role in mediating these interactions^1,2. In the dynamic soil environment, organisms ranging from plant roots and bacteria to fungi and nematodes produce and respond to a diverse array of VOCs that originate from various catabolic pathways, yielding a wide range of structurally and functionally distinct compounds^3,4,5. VOCs are typically small, odorous molecules ( < C15) with low molecular mass ( < 300 Da), high vapor pressure, low boiling point, and lipophilic properties^1,2. These characteristics enable rapid volatilization and diffusion of VOCs through both gaseous and aqueous phases within the soil’s porous matrix, facilitating short- and long-distance interactions over millimeter-to-centimeter scale^6,7. However, VOC transport is strongly constrained by compound-specific traits and soil properties, such as texture, moisture content, and pore connectivity, as well as by diffusion versus advective processes (e.g., airflow or preferential flow through macropores)⁶. In this context, clearly defining the spatial scales of VOC-mediated interaction is crucial.

The diffusion dynamics of inorganic gases, such as CO₂ are well-documented within a narrow rhizosphere gradient (0.5–4 mm)⁸. In contrast, only a limited number of studies have explored the effect of distance on VOC-mediated interactions. A study using soil-filled olfactometers has demonstrated that root VOCs can attract beneficial bacteria from distances of up to 12 cm². Similarly, a field study employing air- and water-filled random- walk channels showed that nematodes can sense a root-produced terpene (E)-b-caryophyllene, from a much longer distance of 50 cm^9,10. However, both studies relied on artificial systems that reduce the physical constraints typical of natural soil; thus, the reported distances likely represent the upper detection limits rather than ecologically representative interaction distances. Despite these experimental deficiencies, these findings suggest that the functional significance of VOCs extends far beyond their basic metabolic roles in soils¹¹. The VOCs are integral to an organism’s growth, survival, and ecological strategy, serving key functions in stress tolerance, intra- and interspecific communication, and direct and indirect defense mechanisms by modulating complex signaling pathways at multiple trophic levels^12,13. Moreover, VOCs are a fundamental language of soil’s hidden networks, and potent chemical signals that alter the physiology and behavior of any organism that detects them¹⁴. This long-distance signaling provides a strategic advantage, allowing producers to modulate their environment, preemptively inhibit competitors, or attract beneficial partners¹⁵.

Much of our current understanding of VOC-mediated interactions is derived from simplified experimental systems, such as headspace assays, olfactometers, and microcosms, which likely overestimate transport distances and interaction strengths relative to structurally complex field soils¹⁶. There is therefore a need to explicitly account for spatial scale, soil physical constraints, and methodological limitations when interpreting purported “long-distance” VOC-mediated interactions. Moreover, to date, most research remains primarily focused on one-way interactions involving microbial VOCs and, to a lesser extent, plant root VOCs or protists, rather than addressing their broader ecological roles¹⁶. Understanding VOC-mediated communication is crucial to unraveling the complex dynamics of the belowground world, characterized by profound interconnectedness¹⁷. This perspective article, therefore, synthesizes the current knowledge in a nutshell to identify critical gaps and propose future directions to stimulate interdisciplinary collaborative research.

Plants are active participants in intricate ecological networks, employing sophisticated communication strategies to navigate the challenges of biotic and abiotic stresses¹⁸. A primary mechanism for this communication is the release of VOCs, which act as real-time indicators of a plant’s physiological state¹⁹. VOCs play an important role in plant-plant communication both above and below ground (Fig. 1A)^19,20,21,22.

Aboveground, plant-plant chemical communication mediated by VOC signaling has implications for plant health and performance, including improving plant growth and stress resistance, modulating rhizosphere microbiome, and attracting mutualists, such as pollinators and beneficial microbes while repelling antagonists, such as herbivores and pathogens^22,23. The established role of VOCs in aboveground interactions has spurred interest in their functions belowground. Root-emitted VOC profiles are highly specific, shaped by the plant’s genotype, and change in response to environmental or stress conditions^24,25. Root VOCs enable plants to identify their neighbors, adding a layer of complexity to root-root interactions²⁶ (Fig. 1A). They diffuse efficiently through soil pore networks, where they perform key biological roles: enhancing bacterial quorum sensing (QS), attracting nematodes, and recruiting beneficial microbes^27,28. In addition, VOCs can function as chemical cues or signaling molecules mediating intra- and interspecific plant interactions in the rhizosphere¹⁶. For example, specific root VOCs can inform the health status of a plant (“emitter plant”), resulting in physiological responses in a neighboring plant (“receiver plant”)²⁶. However, only a few studies have dealt with VOC-mediated plant-plant interactions belowground. For example, in a soil compartment study, jasmonic acid-induced Picea abies plants produce greater root VOC signals, which lead the adjacent Fagus sylvatica plant to ramp up root VOC release and early priming of herbivore-induced defenses²⁹. Similarly, a VOC, (-)-loliolide, together with jasmonic acid, was shown to participate in plant neighbor detection and subsequent allelochemical responses in wheat in a soil pot experiment³⁰. Conversely, a soil compartment study demonstrated that root-emitted VOCs from spotted knapweed (Centaurea stoebe L.), especially the sesquiterpene (E)-β-caryophyllene, did not affect the accumulation of defensive secondary metabolites but modulated protein and carbohydrate levels in roots of sympatric Taraxacum officinale plants, and increased the growth of root herbivore Melolontha melolontha on T. officinale plants²⁶.

These studies, conducted under controlled conditions, reveal that plant-to-plant interactions, mediated by VOCs, can activate specific metabolic pathways to cope with biotic and abiotic stresses, but molecular mechanisms remain largely unresolved. Elucidating intra- and interspecific plant communication belowground requires investigations conducted under ecologically realistic conditions, where VOC concentrations, diffusion ranges, and persistence may differ substantially from those in simplified experimental systems. Although above-ground approaches (e.g., enclosure-based flux measurements and isotopic tracing) provide a strong conceptual and technical foundation, their application below-ground necessitates methodological adaptation³¹. Specifically, soil physicochemical properties, sorption-desorption dynamics, and microbial VOC degradation must be accounted for using root/soil chamber systems, in situ sampling, and stable-isotope labeling approaches to resolve the roles of root-emitted VOCs in both inter- and intra-plant communication.

The intricate plant-microbe interactions are fundamental to plant growth and health, and they play a critical role in sustaining agricultural productivity and ecosystem functioning (Fig. 1B)³². In the soil, VOCs serve as essential signaling molecules, facilitating cross-kingdom communication between microbes and plants^2,13.

Root VOCs play a crucial role in mediating a range of ecological processes, from recruiting microbes and regulating their activity to suppressing pathogens^16,33,34. As demonstrated in an olfactometer study, plants like Carex arenaria alter their root VOC profiles to attract specific bacteria with antifungal properties over long distances when attacked by a fungal pathogen, Fusarium culmorum³⁵. In another controlled soil pot study, plant root VOC profile changes induced by different manganese levels influenced the diversity and composition of the rhizosphere microbiome, with increased abundance of beneficial genera³⁶.

In an in vitro study, specific microbial VOCs, such as 2,3-butanediol, 2-pentylfuran, and indole, have been reported to enhance nutrient acquisition (e.g., nitrate and iron) by increasing their uptake or availability by acidifying the rhizosphere, and promote root development and overall plant growth by modulating hormonal signaling (i.e., auxin, cytokinin, ethylene)³⁷. Another in vitro study showed that the microbial VOC dimethyl disulfide can be utilized by plants as a sulfur source³⁸. In addition, microbial VOCs like tridecane and 2,3-butanediol can induce plant tolerance to abiotic and biotic stresses³⁹. VOCs produced by Bacillus and Pseudomonas species have been shown to trigger plant resistance against pathogens like Ralstonia solanacearum, Erwinia carotovora, and Phyllosticta citricarpa by inducing antioxidant activity and hormonal signaling (i.e., salicylic acid, jasmonic acid, and ethylene signaling)^39,40,41. VOCs emitted by Alcaligenes, Bacillus, Pseudomonas, and Paraburkholderia genera have been found to induce resistance in plants against drought stress by inducing stomatal closure to reduce water loss, and against salinity stress by inducing accumulation of compatible solutes, such as proline and choline or reducing sodium accumulation^42,43,44. Similarly, microbial VOCs, such as benzaldehyde and 1,2-benzisothiazol-3(2H)-one effectively suppress major pathogens like Rhizoctonia solani and Xanthomonas oryzae by distorting and damaging their cell structure, metabolic activity, and suppressing virulence traits (i.e., motility, biofilm formation), thus helping plants to tackle pathogen infestation⁴⁵.

VOC mixtures emitted by microbial communities can have contrasting effects compared to those produced by single species. For example, bacterial community-produced VOCs had different effects on Arabidopsis growth and root architecture than the sum of the effects of individual strains⁴⁶. In another in vitro study, the strongest plant growth promotion was observed at the lowest microbial community richness, whereas intermediate richness promoted pathogen suppression by VOCs (Fig. 1B)⁴⁷. In contrast, another in vitro study suggested that higher species richness within a bacterial genus increases both VOC-mediated pathogen suppression and plant growth promotion⁴⁸. While most studies have assessed one-way VOC-mediated interactions, a recent glass chamber study showed that methyl jasmonate, the volatile form of the plant hormone jasmonic acid, promotes the formation of complex microbial biofilms, reshapes microbial community structure, and stimulates VOC emissions, ultimately enhancing plant growth³⁴.

Plant and microbe-emitted VOCs mediate a myriad of effects on each other, from signaling to modulation of physiology and bioactivity⁴⁹. However, most available knowledge comes from in vitro studies, which often use a single microbe or plant under artificial conditions. These studies offer limited ecological predictability and have major limitations, such as VOC concentrations far exceeding field-relevant levels, absence of trophic complexity, and lack of soil sorption-desorption, diffusion, and microbial degradation constraints. While in vitro studies are essential for mechanistic discovery, advancing the field requires integrative, soil-based, and field-linked approaches that explicitly account for microbial complexity, soil physicochemical properties, and realistic VOC concentrations.

Microorganisms, including bacteria, archaea, fungi, and protists, rely heavily on chemical signaling to gather information⁵⁰ (Fig. 2A). The primary function of this communication in microbes is to coordinate population-wide behavior, a process essential for initiating both beneficial and harmful interactions with other organisms^47,51. While traditional studies focused on non-volatile cues (exudates, peptides, quorum-sensing signals)^52,53,54, recent discoveries reveal that microbial VOCs act as crucial signals in intra- and inter-microbial interactions, operating at low concentrations over long distances^35,48.

There are many reports based on in vitro studies about the antagonistic effect of VOCs produced by a biocontrol microbe against a pathogenic microbe^13,55. For example, VOCs, such as benzaldehyde and 1-methyl naphthalene, produced by Bacillus, Serratia, and Pseudomonas species, inhibit the growth and virulence traits (i.e., motility, biofilm formation) of pathogens, such as Agrobacterium tumefaciens and R. solanacearum by altering the transcriptional expression of several genes involved in pathogenicity^41,56. On the other hand, VOCs produced by some microbes can promote the growth of neighboring microbes. For example, Collimonas pratensis and Serratia plymuthica VOCs induced the growth and motility of the beneficial rhizosphere bacteria P. fluorescens Pf0-1⁵⁷. In a soil microcosm study, the VOCs of root exudate-consuming bacteria stimulated the growth of distant nutrient-limited bacteria⁵⁸. Similarly, based on evidence from an in vitro study, microbial VOCs like trimethylamine work as a signal to induce the exploration of Streptomyces venezuelae at a distance⁵⁹. Interestingly, the effects that the same VOCs have on different microbial species can also differ. For example, dimethyl sulfide and trimethyl sulfide inhibit the growth of R. solani and F. culmorum but promote the growth of Pseudomonas species⁶⁰. Trimethylamine increases Streptomyces’ ability to move rapidly through solid surfaces but inhibits the growth of Bacillus subtilis and Micrococcus luteus^37,60.

While these examples show unidirectional antagonistic and mutualistic effects of microbial VOCs, a few in vitro studies describe the bidirectional role of VOCs in microbe-microbe interactions (Fig. 2A). For example, when two microbes were exposed to each other’s VOCs, the metabolic activity of Paenibacillus polymyxa was increased without a change in growth, whereas Verticillium longisporum showed reduced growth and metabolism and upregulated stress responses, including antimicrobial VOC production⁶¹. In another study, with two pathogens exposed to each other’s VOCs, the bacterial pathogen R. solanacearum exhibited reduced production of extracellular polysaccharides, while the fungal pathogen Aspergillus flavus responded by decreasing conidia formation and increasing aflatoxin production⁶². These two examples suggest that VOC exchange between two microbes not only influences the physiology of interacting partners but also the virulence traits, which are highly relevant for the outcome of infection. Structurally diverse, VOCs can modulate gene expression in distant recipients, triggering processes, such as growth, antibiotic production, biofilm formation, motility, and virulence^63,64,65. The study of microbial VOCs is thus essential for elucidating community dynamics in the complex soil environment, where volatile metabolites may determine the balance between health and disease⁶⁵.

These studies reveal that VOCs mediate antagonistic to mutualistic interactions among microbes by modulating physiology and gene transcription^63,64,65. However, almost all studies are conducted under artificial conditions, restraining their ecological relevance. Key limitations include unrealistic VOC concentrations and exposure times, oversimplification of the complexity arising from soil matrix effects, and neglect of microbial VOC consumption and transformation. Further, little is known about the perception of VOCs. Several mechanistic routes for VOC perception are proposed: (1) partitioning into membranes and perturbation of fluidity, which triggers envelopes and stress responses^52,53,54; (2) diffusion into the cytosol, where VOCs directly modulate enzymes, transcription factors, or redox state^33,45, and (3) modulation of existing signaling systems, such as two‑component systems and quorum-sensing circuits^55,66. Moreover, there is no information about VOC-mediated community-to-community interactions among microbes. Available knowledge indicates that in belowground microbial interactions, responses to VOCs are potentially coevolutionary and strongly depend on the interacting partners⁵⁵. Advancing the field requires a shift towards ecologically grounded experimental designs that integrate real soils, intact microbial communities, dynamic VOC measurements, and isotope-based tracing across multiple spatial and temporal scales.

In the soil, the chemical interactions between pathogens and biocontrol microbes may extend to predator-prey dynamics (Fig. 2B), where VOCs help locate prey over long distances^32,67. Protists, known as key bacterial predators, play an important role in the soil food web and not only shape microbial communities through selective feeding but also significantly affect carbon allocation and nutrient cycling in the soil-plant interphase⁶⁸.

In a microcosm study, Schulz-Bohm et al. tested various VOC-mediated interactions between phylogenetically different soil bacteria and protists, comparing those with direct trophic interactions⁶⁹. They demonstrated that VOCs produced by the soil bacterium Collimonas pratensis Ter9126, such as β-linalool and δ-cadinene, stimulated the growth and motility of protists Vermamoeba and Tetramitus, indicating their role in providing early information about suitable prey⁶⁹. Conversely, VOCs from some other bacteria, such as Burkholderia spp. and Paenibacillus spp. inhibited the growth of the protists Vermamoeba and Saccamoeba; however, the populations of these protists increased when directly preying upon Burkholderia and Paenibacillus species⁶⁹. Similarly, VOCs produced by Pseudomonas stimulated the growth of protist Tetramitus while it inhibited Tetramitus in a direct trophic interaction⁶⁹. In another trap network field study, geosmin, produced by a soil bacterium, Streptomyces coelicolor M145, influenced the excitement (waking up) and predation response of soil protists⁷⁰. Three protists, Colpoda sp., Cercomonas sp., and Acanthamoeba castellanii, showed a significant excitement when exposed to geosmin, but the feeding preferences of the protists showed variation. Two protists (Cercomonas sp. and A. castellanii) appeared to be less likely to predate geosmin-producing bacterial strains, suggesting geosmin production by bacteria may serve as a deterrent to predation by protists⁷¹.

Besides bacterivorous protists, facultative microphagous protists also exist in soil and mainly feed on yeast and fungal spores or hyphae^68,72. It is well known that soil fungi produce a wide range of VOCs involved in various interactions²². Therefore, it is plausible that fungal VOCs could also play an important role in communication between soil fungi and protists underground, but no information is available. Moreover, soil protists also produce VOCs. For example, an in vitro study showed that Dictyostelium discoideum produces terpenes that have been suggested to be involved in defense mechanisms, for example, to repel nematode predators⁷³.

Predatory nematodes and mites hunt entirely by scent^4,74 and navigate the tortuous air-filled pores, following faint chemical trails released by their prey (Fig. 2B)⁴. A prey’s VOC signatures can betray its location, and a predator’s success depends on its ability to interpret the chemical VOC trails and navigate their complexities⁷⁵. In studies using mesh cages and traps in the field, VOC blends emitted by root weevil Diaprepes abbreviatus-infested citrus roots were shown to attract entomopathogenic nematodes^76,77. Among all the VOCs emitted, one VOC, pregeijerene, was sufficient to attract entomopathogenic nematodes and bacterivorous nematodes (Acrobeloides) and to increase the mortality rate of insect larvae⁷⁸. In two in vitro studies, entomopathogenic nematodes exhibited species-specific chemotactic responses to VOCs released by insect-damaged roots, indicating these compounds can function as below-ground host-location cues^9,79. However, their effects vary from attraction to repulsion depending on nematode species and compound identity, highlighting the complexity of tritrophic signaling in soil ecosystems⁸⁰.

Both prey and predators can detect VOC signals to assess favorable or hostile conditions and adjust their behavior accordingly. However, these processes remain insufficiently understood and require further investigation under ecologically realistic conditions. For example, it is unclear how organisms discriminate among signals associated with food, competitors, or threats, and whether they can exploit or mimic VOC profiles within the complex and heterogeneous soil environment. Current knowledge suggests co-evolutionary dynamics in predator-prey and microbial interactions⁸¹, but lacks experimental evidence.

The VOCs blend of soil organisms is further supplemented by compounds originating from the decomposition of organic material, and inputs from organic fertilizers and irrigation⁸². The journey and impact of a VOC in soil are dictated by a complex interplay between the compound’s own properties and the soil environment^81,82. Key chemical traits, such as molecular size, vapor pressure, boiling point, Henry’s constant (K_H), and lipophilicity, determine a VOC’s behavior: smaller VOCs with high vapor pressure, low boiling point, and medium K_H and lipophilicity diffuse faster^82,83. Soil texture, structure, moisture, and organic matter content also influence how far a VOC can travel^84,85. For instance, a field study showed that a waterlogged, compacted soil can act as a silent tomb for VOC signals, whereas a well-aerated, moist loam provides an ideal conduit for chemical communication⁸⁴.

Once released into the soil matrix, VOCs may follow multiple fates: they can escape to the atmosphere, absorb onto mineral or organic surfaces, undergo microbial transformation or degradation, be taken up by plant roots, or become trapped in soil pore spaces^82,83. Their movement in soil is propelled by two main forces: diffusion (driven by concentration gradients) and advection (driven by pressure, gravity, or thermal gradients)⁸⁶. In addition to gas-phase movement, VOCs can also be transported via bulk water flow. Within the aqueous phase, a largely hidden subsurface network formed by root channels, fungal mycelia, and soil fauna burrows may function as preferential flow paths, effectively acting as “superhighways” that facilitate the long-distance movement of VOCs through the soil matrix^87,88.

Soils can actively retain VOCs through adsorption into organic matter and mineral surfaces. The dynamics of this adsorption and subsequent desorption are highly specific and are influenced by the type of VOC and soil properties. For example, VOC desorption increases in soils with finer particles and smaller molecular sizes, and higher VOC vapor pressure enhances their diffusion and retention within nanopores⁸⁹. Microbial degradation or transformation of VOCs in soil also likely limits the signaling distance⁹⁰. For example, a study used ¹⁴C-tracer incubations to demonstrate that soil microorganisms rapidly mineralize, i.e., completely degrade a diverse suite of VOCs, underscoring the crucial but underrecognized role of soil microbial activity in regulating soil VOC processes⁹¹. Jiao et al. showed that microbial VOC uptake rate exceeded the production rate when VOCs were readily available⁹². Similarly, soil VOC emission peaks under high temperatures and low moisture conditions, suggesting a potential seasonal pulse⁸³.

Consequently, the effective radius of a VOC’s influence is the function of its own properties combined with the physicochemical state and microbial activities of its environment. Collectively, these findings propose a compelling paradigm: VOCs may extend local belowground interactions over considerable distances, potentially linking the rhizosphere with the broader bulk soil bidirectionally to form an extensive plant metarhizobiome³. Studies on VOC movement in soil have advanced substantially, but several critical gaps remain. A system-level understanding that conceptualizes VOC movement as a dynamic, biologically filtered process, integrating physical, chemical, biological, and ecological dimensions, remains a critically under-explored frontier, pointing the way for future research.

Previously underestimated, the capacity of soil organisms to emit and respond to VOCs is now recognized as a major driver of belowground interactions. VOCs travel through both air‑ and water‑filled pores, allowing messages to propagate across heterogeneous soil matrices well beyond direct contact zones^7,93. However, there is also a viewpoint that VOCs play a minor role in soil, considering sink functions of soil for VOCs through microbial uptake, and methodological challenges in bringing controlled environment findings to actual field conditions^92,94. In our opinion, this controversy lies not in whether VOCs can mediate interactions, but rather in how, when, and to what extent these interactions function in natural, complex soil ecosystems. We identify the following knowledge gaps as critical for the field to move forward:

1. 1.

   There is a need to improve our understanding of the impacts of VOC blends. Most mechanistic work on soil VOCs arises from in vitro assays under nutrient‑rich conditions, often testing a single compound against a single target. Yet organisms emit VOC blends, and mixture composition, concentration, and ratios can invert or amplify biological outcomes relative to isolated compounds⁵. Co‑cultures and small synthetic community experiments already show that microbial interactions reshape VOC bouquet chemistry and bioactivity⁹⁵, underscoring why single‑molecule tests can be misleading. Moreover, enantiomers may have different biological functions, for example, the orange-like odor of (R)-(+)- limonene and the turpentine-like odor of the (S)–(–)- limonene, due to differences in specific fit at the active site of the enzyme or receptor.

2. 2.

   We lack understanding of the molecular mechanisms by which VOCs are perceived by the receiver organism. VOC perception is best regarded as an emergent property arising from membrane interactions, metabolic sensing, and redox signaling across organisms, rather than a receptor-driven system analogous to animal olfaction^96,97,98. In plants, potential VOC targets include membrane fluidity, ion flux signaling (Ca²⁺-permeable channels), redox and reactive oxygen species signaling, transcriptional regulation, and receptor-like kinases^96,99,100. In microbes, VOCs may be perceived through metabolic sensing, two-component regulatory systems, redox and oxidative stress sensing, quorum-sensing interference, and membrane transporters and efflux pumps. In nematodes, VOC perception likely involves G-protein-coupled receptors, ion channel modulation, and neuroendocrine signaling, whereas in protists, it may rely on GPCR-like and histidine kinase receptors, metabolic and redox sensing, and membrane-based mechanisms^101,102. Similarly, while numerous effects of VOCs (e.g., on pathogen inhibition, biofilm formation) are documented, the precise molecular mechanisms and signaling cascades, whether mediated by active signal transduction or simple absorption, remain largely opaque.

3. 3.

   We lack a comprehensive understanding of how VOC-mediated interactions function within complex, multi-trophic soil food webs beyond simple pairwise interactions. Also, the spatial-temporal range of VOC-mediated interactions belowground is not well explored, leaving the broader ecological spectrum of VOCs underexplored.

4. 4.

   Effects of altered environmental factors, including temperature, water content, and nutrient availability, on soil VOC concentrations and processes mediated by them are poorly understood. The high vapor pressure and volatile nature make VOC fluxes exquisitely sensitive to temperature, moisture, texture, and redox dynamics that climate change is rapidly reshaping¹⁵. Drought, a hallmark of contemporary climate change, restructures this chemical language by depressing microbial CO₂ respiration while enhancing the production and emission of VOCs, thereby rerouting soil carbon metabolism toward VOC losses^103,104. Similarly, fertilizer inputs or deposition modulate soil microbial community structure and carbon processing by shifting resource stoichiometry, pH, and redox microenvironments, with downstream effects on VOC emissions⁸². Temperate Forest experiments show that soil warming and simulated nitrogen deposition can elevate soil VOC fluxes seasonally by modulating VOC production pathways, sorption/uptake kinetics, and emissions¹⁰⁵. Yet we know remarkably little about how shifting temperature and moisture regimes, and fertilization, modulate the rate, range, and composition of VOC production and exchanges in situ, such as the ratio of gas-filled to water-filled soil pores, which may show considerable seasonality and range variations in VOC-mediated interactions under realistic wet-dry cycles.

5. 5.

   The degradation of organic (i.e., plant residues) and chemical inputs (i.e., pesticides, herbicides) generates VOCs that can restructure microbial communities and enzyme systems, thereby influencing VOC production and consumption dynamics. Similarly, microplastics are now pervasive in agricultural soils from mulches, coated fertilizers, composts, and wastewater inputs¹⁰⁶. Microplastic residues not only absorb hydrophobic organics (including VOCs or their precursors), alter soil porosity and water retention, and remodel microbial communities¹⁰⁷, but also release their own VOCs via degradation. Plastic residues can significantly alter the composition of volatile blends emitted from soil¹⁰⁸. These perturbations may mask or interfere with native chemical signals and alter both the quantity and composition of microbially derived VOCs in field soils, an overlooked aspect of soil VOC dynamics.

Addressing these knowledge gaps will require a shift in both scale and methodology. To advance a mechanistic understanding of putative receptors, channels, and downstream signaling nodes, we advocate CRISPR‑based genetic screens, barcoded transposon libraries, and quantitative proteomics/phosphoproteomics under VOC exposure. These advanced molecular methods could be coupled with position‑specific isotope tracer studies to partition VOC production from consumption pathways and identify the responsible organisms in the soil ecosystem. Ecologically, experimental designs should move beyond binary assays toward VOC mixtures and synthetic communities that capture synergies and antagonisms among bacteria, fungi, protists, nematodes, and plant roots. These ideas can be further extended to explicitly track community reassembly and VOC-mediated interactions under climate change and in the presence of pollutants. Spatial–temporal quantification should pair high‑frequency online measurements (e.g., Proton-transfer-reaction mass spectrometry) with pore‑scale sampling and reactive‑transport modeling to map diffusion fields through heterogeneous soil architectures and across wet–dry transitions. Analytical advances are equally important as correct VOC identification in mixtures (including chiral separation, given the divergent bioactivities of enantiomers) is a prerequisite for reproducible results in natural substrates. Understanding the production/consumption dynamics of soil VOCs and their long-distance roles is key to unraveling the complex dynamics of biotic interactions in the belowground world. Future research unraveling this chemical lexicon will not only deepen our understanding of soil ecology but also open new avenues for sustainable agriculture, where we might one day “eavesdrop” on these signals to enhance crop health and productivity.