Sergio Rasmann

• Professor (Full) at University of Neuchâtel

Over time, soils undergo qualitative and structural changes under the influence of climate, geomorphic processes, parent material weathering, and vegetation, ultimately developing into unique soil types and profiles. Although these pedological drivers are conserved globally, it remains unclear to what extent different soil profiles undergo similar...

BACKGROUND Meloidogyne incognita root‐knot nematodes (RKNs) pose a significant threat to crops, ranking among the most dangerous plant pathogens globally. Entomopathogenic fungi (EPF) have been reported to reduce populations of plant‐pathogenic nematodes, including M. incognita. Moreover, the fermentation broths of some EPF strains have displayed b...

A recent paradigm shift in ecology supports that the classic functional trait space should be extended to include the metabolome. Accordingly, metabolomic signatures differ between plant species or genotypes depending on where they grow along ecological gradients. Yet, it remains unclear whether environmental gradients alone induce intraspecific ph...

The asynchronous upward shift of insect herbivores and plants towards higher elevations following climate warming is anticipated to generate novel plant–insect interactions. As generalist herbivores shifting to higher elevations might incorporate novel plant species into their diet, high‐elevation plant communities could experience increased herbiv...

Global change is causing unprecedented degradation of the Earth’s biological systems and thus undermining human prosperity. Past practices have focused either on monitoring biodiversity decline or mitigating ecosystem services degradation. Missing, but critically needed, are management approaches that monitor and restore species interaction network...

Tomato, a globally significant crop, faces continuous threats from pests and pathogens, necessitating alternative approaches to reduce chemical inputs. Beneficial soil microbes, such as arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR), offer promising solutions by enhancing plant growth and pest tolerance. However,...

Terrestrial plants naturally produce chemical signals to attract beneficial insects or repel harmful pests. These inherent plant attributes offer promising opportunities for eco‐friendly pest control in agriculture, particularly through the push–pull intercropping technique. However, our understanding of potential repellent plants and their effecti...

Artificial light at night (ALAN) is a recognized threat not only to urban areas but also to more remote habitats including forests. Advancements in LED technology offer potential for streetlight infrastructure with minimized disruptive impact on ecosystems. Light dimming ranges among the most promising ALAN‐mitigation measures. Despite being essent...

Research has shown that soil-borne beneficial microorganisms can enhance plant growth, productivity, and resistance against pests and pathogens and could thus serve as a sustainable alternative to agrochemicals. To date, however, the effect of soil-beneficial microbes under commercial crop production has been little assessed. We here investigated t...

Plants can perceive and respond to external stimuli by activating both direct and indirect defences against herbivores. Soil‐dwelling entomopathogenic nematodes (EPNs), natural enemies of root‐feeding herbivores, carry symbiotic bacteria that grow and reproduce once inside arthropod hosts. We hypothesized that the metabolites produced by EPN‐infect...

Plants respond to attacks by herbivores and pathogens by releasing specific blends of volatile compounds and the resulting odor can be specific for the attacking species. We tested if these odors can be used to monitor the presence of pests and diseases in agriculture. Two methods were used, one employing piezoresistive membrane surface stress sens...

Rising temperatures and higher atmospheric CO2 levels can potentially increase plant photosynthesis and boost forest productivity, thereby spurring litter inputs to soils on a global scale. Understanding the feedback loops between increased litter inputs and soil biota activity will allow for better prediction of organic matter and carbon (C) cycli...

Asynchronous migration of insect herbivores and their host plants towards higher elevations following climate warming is expected to generate novel plant–insect interactions. While the disassociation of specialised interactions can challenge species' persistence, consequences for specialised low‐elevation insect herbivores encountering novel high‐e...

Understanding the distribution of hundreds of thousands of plant metabolites across the plant kingdom presents a challenge. To address this, we curated publicly available LC-MS/MS data from 19,075 plant extracts and developed the plantMASST reference database encompassing 246 botanical families, 1,469 genera, and 2,793 species. This taxonomically f...

Root exudation could be harnessed for ecological and applied research

Microorganisms associated with plant roots significantly impact the quality and quantity of plant defences. However, the bottom-up effects of soil microbes on the aboveground multitrophic interactions remain largely under studied. To address this gap, we investigated the chemically-mediated effects of nitrogen-fixing rhizobia on legume-herbivore-pa...

Research is showing that soil-borne beneficial microorganisms can enhance plant growth, productivity, and resistance against pests and pathogens, and could thus serve as a sustainable alternative to agrochemicals. To date, however, the effect of soil beneficial microbes under commercial crop production has not been fully assessed. We here investiga...

Parthenium hysterophorus L. (Asteraceae) is an aggressive annual herbaceous weed which causes severe yield losses on a global scale. However, the precise impact of this weed in several countries is not yet known. To assess the impact of P. hysterophorus on maize crop losses in Pakistan, a 2 year field experiment was carried out at the CABI Rawalpin...

Activating the natural immunity of plants against insect herbivores scores within the global targets of improving food security, while simultaneously reducing pesticide load into the environment. Chitosan nanoparticles (CNPs) are...

Since 1982, we studied changes in soil properties across diverse ecosystems, observing that physicochemical changes varied depending on soil type. Over time, the carbon-to-nitrogen ratio generally increased, and these soil changes were closely linked to local climatic conditions. Looking ahead, future warmer and drier conditions could spur more rap...

Plant enemies can indirectly affect pollinators by modifying plant traits, but simultaneous tests of herbivore and pathogen effects are lacking, and the role of floral volatiles has seldom been assessed. In this study, we tested for indirect effects of insect herbivores and pathogens on pollinator attraction via altered floral volatile emissions, a...

Interactions between plants and herbivores are central in most ecosystems, but their strength is highly variable. The amount of variability within a system is thought to influence most aspects of plant-herbivore biology, from ecological stability to plant defense evolution. Our understanding of what influences variability, however, is limited by sp...

BACKGROUND Root‐knot nematodes (RKNs), including Meloidogyne species, are among the most destructive plant‐parasites worldwide. Recent evidence suggests that entomopathogenic fungi (EPF) can antagonize RKNs. Such antagonistic effects are likely mediated by toxic metabolites, including volatile organic compounds (VOCs), produced by the fungi. Howeve...

The metabolome is the biochemical basis of plant form and function, but we know little about its macroecological variation across the plant kingdom. Here, we used the plant functional trait concept to interpret leaf metabolome variation among 457 tropical and 339 temperate plant species. Distilling metabolite chemistry into five metabolic functiona...

Seed predation by insect herbivores reduces crop production worldwide. Foraging on seeds at pre-dispersal generally means that females need to find the suitable host plant within a relatively short timeframe in order to synchronize larval development with seed production. The mechanistic understanding of host finding by seed pests can be harnessed...

The diversity of specialized molecules produced by plants radiating along ecological gradients is thought to arise from plants' adaptations to local conditions. Therefore, closely related species growing in similar habitats should phylogenetically converge, or diverge, in response to similar climates, or similar interacting animal communities. We h...

Humus forms and organic matter decomposition are influenced by climate, plants and soil decomposers. Yet, whether different humus forms could be experimentally linked to litter decomposition has still to be fully assessed. To assess the link between humus systems and organic matter decomposition, we worked in two regions of the Swiss Alps (Valais a...

Plant-plant signalling via volatile organic compounds (VOCs) has been studied intensively, but its contingency on abiotic conditions (e.g., soil nutrients, drought, warming) is poorly understood. To address this gap, we carried out a greenhouse experiment testing whether soil nutrients influenced signalling between potato (Solanum tuberosum) plants...

In pioneering studies on plant-aphid interactions, we have observed that Vicia faba plants infested by aphids can transmit signals via the rhizosphere that induce aboveground defence in intact, neighbouring plants. The aphid parasitoid Aphidius ervi is significantly attracted towards intact broad bean plants grown in a hydroponic solution previousl...

Poaching for horns and tusks is driving declines of megaherbivores worldwide, including the critically endangered African black rhinoceros (Diceros bicornis). By proactively dehorning entire rhinoceros populations, conservationists aim to deter poaching and prevent species loss. However, such conservation interventions may have hidden and underesti...

Organic matter (OM) decomposition has been shown to vary across ecosystems, suggesting that variation in local ecological conditions influences this process. A better understanding of the ecological factors driving OM decomposition rates will allow to better predict the effect of ecosystem changes on the carbon cycle. While temperature and humidity...

Arbuscular mycorrhizal fungi (AMF) have evolved associations with roots of 60% plant species, but the net benefit for plants vary broadly from mutualism to parasitism. Yet, we lack a general understanding of the evolutionary and ecological forces driving such variation. To this end, we conducted a comparative phylogenetic experiment with 24 species...

The metabolome is the biochemical basis of plant form and function, but we know little about its macroecological variation across the plant kingdom. Here, we used the plant functional trait concept to interpret leaf metabolome variation among 457 tropical and 339 temperate plant species. Distilling metabolite chemistry into five metabolic functiona...

Background and Aims To counteract the ongoing worldwide biodiversity loss, conservation actions are required to re-establish populations of threatened species. Two key factors predominantly involved in finding the most suitable habitats for endangered plant species are the surrounding plant community composition and the physicochemical parameters o...

Main conclusion VOC emissions increased with herbivore load, but this did not result in concomitant increases in resistance in neighbouring plants, suggesting that communication occurred independently of herbivore load in emitter plants. AbstractHerbivore-damaged plants emit volatile organic compounds (VOCs) that can alert neighbours and boost thei...

Nanosilicon applications have been shown to increase plant defenses against both abiotic and biotic stresses. Silicon quantum nanodots (Si NDs), a form of nanosilicon, possess excellent biological and physiochemical properties (e.g., minimal size, high water solubility, stability, and biocompatibility), potentially making them more efficient in reg...

While mechanisms of plant–plant communication for alerting neighbouring plants of an imminent insect herbivore attack have been described aboveground via the production of volatile organic compounds (VOCs), we are yet to decipher the specific components of plant–plant signalling belowground. Using bioassay‐guided fractionation, we isolated and iden...

Aims Negative interactions in the rhizosphere between entomopathogenic nematodes (EPNs) and plant-parasitic nematodes, such as root-knot nematodes (RKNs), have been documented over the past two decades but the mechanisms and dynamics of such interactions remain largely elusive. Methods Here, we evaluated the effect of the inoculation position of t...

It has been proposed that plant-plant signalling via herbivore-induced volatile organic compounds (VOCs) should be stronger between closely related than unrelated plants. However, empirical tests remain limited and few studies have provided detailed assessments of induced changes in VOCs emissions across plant genotypes to explain genetic relatedne...

It has been estimated that between 40 and 60 % of the assimilated carbon is diverted to the roots and released in the rhizosphere in form of root exudates. Root exudates thus define a complex mixture of low and high molecular weight compounds, including carbohydrates, amino acids, organic, and proteins, but also a broad spectrum of specialized mole...

Background and Aims – To counteract the ongoing worldwide biodiversity loss, conservation actions are required to re-establish and regenerate populations of threatened species. Two key factors predominantly involved in finding the most suitable habitats for endangered plant species are the surrounding plant community composition and the physicochem...

To withstand the surge of species loss worldwide, (re)introduction of endangered plant species has become an increasingly common technique in conservation biology. Successful (re)introduction plans, however, require identifying sites that provide the optimal ecological conditions for the target species to thrive. In this study, we propose a two‐ste...

Airborne plant communication is a widespread phenomenon in which volatile organic compounds (VOCs) from damaged plants boost herbivore resistance in neighbouring, undamaged plants. Although this form of plant signalling has been reported in more than 30 plant species, there is still a considerable knowledge gap on how abiotic factors (e.g. water av...

Deceptive pollination often involves volatile organic compound (VOC) emissions that mislead insects into performing non-rewarding pollination. Among deceptively pollinated plants, Arum maculatum is particularly well-known for its potent dung-like VOC emissions and specialized floral chamber, which traps pollinators—mainly Psychoda phalaenoides and...

Aims Negative interactions in the rhizosphere between entomopathogenic nematodes (EPNs) and plant-parasitic nematodes, such as root-knot nematodes (RKNs), have been documented over the past two decades but the mechanisms and dynamics of such interactions remain largely elusive. Methods Here, we evaluated the effect of inoculation position of two EP...

Understanding the ecological rules structuring the organization of species interactions is a prerequisite to predicting how ecosystems respond to environmental changes. While the ecological determinants of single networks have been documented, it remains unclear whether network ecological rules are conserved along spatial and environmental gradient...

Introduction A wide range of arbuscular mycorrhizal fungi (AMF) can be applied to agricultural soils as biofertilizers for increasing crop growth and yield. Current research also shows that AMF can stimulate plant defences against a range of herbivores and pathogens. However, to date, the efficient use of AMF in agriculture is largely impaired by o...

Soil nematodes are key components of soil food web and, through their metabolic activities, play a crucial role in soil carbon (C) cycling. Aboveground and belowground plant C inputs can directly, or indirectly via soil microbes, modify nematode abundance and community composition. Aboveground and belowground C inputs differ in chemical composition...

Climate change has various and complex effects on crop pests worldwide. In this review, we detail the role of the main climatic parameters related to temperature and precipitation changes that might have direct or indirect impacts on pest species. Changes in these parameters are likely to favour or to limit pest species, depending on their ecologic...

Ecosystem productivity is largely dependent on soil nutrient cycling which, in turn, is driven by decomposition rates governed by locally adapted below‐ground microbial and soil communities. How climate change will impact soil biota and the associated ecosystem functioning, however, remains largely an open question. To address this gap, we first ch...

A major aim of ecology is to upscale attributes of individuals to understand processes at population, community and ecosystem scales. Such attributes are typically described using functional traits, that is, standardised characteristics that impact fitness via effects on survival, growth and/or reproduction. However, commonly used functional traits...

• Plant communication via airborne volatile organic compounds is a widespread phenomenon by which volatile organic compounds from damaged plants boost herbivore resistance in receiver plants. This phenomenon has been studied only in a handful of crop species. • We tested for communication between potato (Solanum tuberosum) plants in response to her...

Alleviating the adverse effects of abiotic and biotic stress factors on crop plants is essential to achieve higher productivity for satisfying the future food demands of the rapidly-growing global human population. The application of Si nanomaterials (Si NMs) could be an ecologically-sound alternative, as there is evidence that Si NMs could positiv...

The use of engineered nanomaterials (NMs) for agricultural applications is becoming increasingly interesting because NMs have been shown to promote crop yield, and also to some extent, protection against insect...

Soil nematodes are a foremost component of terrestrial biodiversity; they display a whole gamut of trophic guilds and life strategies, and by their activity, affect major ecosystem process, such as organic matter degradation and carbon cycling. Based on nematodes' functional types, nematode community indices have been developed, and can be used to...

Trait based ecology has developed fast in the last decades, aiming to both explain mechanisms of community assembly, and predict patterns in nature, such as the effects of biodiversity shifts on key ecosystem processes. This body of work has stimulated the development of several conceptual frameworks and analytical methods, as well as the productio...

Flowering plants emit complex bouquets of volatile organic compounds (VOCs) to mediate interactions with their pollinators. These bouquets are undoubtedly influenced by pollinator‐mediated selection, particularly in deceptively‐pollinated species that rely on chemical mimicry. However, many uncertainties remain regarding how spatially and temporall...

In recent years, metabolomics has emerged as a pivotal approach for the holistic analysis of metabolites in biological systems. The rapid progress in analytical equipment, coupled to the rise of powerful data processing tools, now provides unprecedented opportunities to deepen our understanding of the relationships between biochemical processes and...

Soil nematodes are a foremost component of terrestrial biodiversity, they display the whole gamut of trophic guilds and life strategies, and by their activity, affect major ecosystem processes, such as organic matter degradation and carbon cycling. Based on nematodes’ functional types, nematode community indices have been developed and can be used...

Forest pests can cause massive ecological and economic damage worldwide. Ecologically-sound solutions to diminish forest insect pest impacts include the use of their natural enemies, such as predators and parasitoids, as well as entomopathogenic fungi, bacteria or viruses. Phytochemical compounds mediate most interactions between these organisms, b...

Theory predicts that a large fraction of phytochemical diversity—the richness of individual chemical compounds produced by plants—governs the complexity of interactions between plants and their herbivores. While the effect of specific classes of chemical compounds on plant resistance against herbivores has been largely documented, the effect of com...

Silicon, in its nanoscale form, has shown plant-promoting and insecticidal properties. To date, however, we lack mechanistic evidence for how nanoscale silicon influences the regulation of plant chemical defenses against herbivore attacks. To address this gap, we compared the effect of Si nanodots and sodium silicate, a conventional silicate fertil...

Significance Phytochemical diversity affects plant fitness and is the source of numerous medicines. Despite this, we know remarkably little about how phytochemical diversity is distributed across the plant kingdom and the environment. To address this challenge, we coupled untargeted metabolomics on 416 grassland vascular plant species across Switze...

Elevational gradients are useful ecological settings for revealing the biotic and abiotic drivers of plant trait variation and plant–insect interactions. However, most work focusing on plant defences has looked at individual traits and few studies have assessed multiple traits simultaneously, their correlated expression patterns, and abiotic factor...

Mountain ecology under climate change Climate warming causes shifts in the distributions of organisms and different organisms may move at different rates, resulting in changes in the composition and functioning of ecological communities. These effects are rarely considered in forecasts about the effects of climate change on biodiversity. Using expe...

Plant communication in response to insect herbivory has been increasingly studied, whereas that involving pathogen attack has received much less attention. We tested for communication between potato (Solanum tuberosum) plants in response to leaf infection by the fungal pathogen Sclerotinia sclerotiorum. To this end, we measured the total amount and...

Aim Ecological gradients are expected to be associated with structural rewiring of species interaction networks. The study of network structures along geographic and ecological gradients, however, remains marginal because documenting species interactions at multiple sites is a methodological challenge. Here, we aimed to study the structural variati...

Entomopathogenic nematodes (EPNs) have been extensively studied as potential biological control agents against root-feeding crop pests. Maize roots under rootworm attack have been shown to release volatile organic compounds, such as (E)-β-caryophyllene (Eβc) that guide EPNs toward the damaging larvae. As yet, it is unknown how belowground ecosystem...

The molecular and physiological mechanisms of how rare earth oxide nanoparticles (NPs) alter radish (Raphanus sativus L.) taproot formation and cracking were investigated in the present study. We compared plants that received suspensions of 10, 50, 100, 300 mg L⁻¹ of La2O3 NPs, 300 m L⁻¹ La2O3 bulk-particles (BPs), 0.8 m L⁻¹ La³⁺, or only water for...

Above- and below-ground herbivory are key ecosystem processes that can be substantially altered by environmental changes. However, direct comparisons of the coupled variations of above- and below-ground herbivore communities along elevation gradients remain sparse. Here, we studied the variation in assemblages of two dominant groups of herbivores,...

Biologists still strive to identify the ecological and evolutionary drivers of phytochemical variation that mediate biotic interactions. We hypothesized that plant species growing at sites characterized by high herbivore pressure would converge to produce highly toxic blends of secondary metabolites, independent of phylogenetic constraints. To addr...

Floral odor is a complex trait that mediates many biotic interactions, including pollination. While high intraspecific floral odor variation appears to be common, the ecological and evolutionary drivers of this variation are often unclear. Here, we investigated the influence of spatially and temporally heterogeneous pollinator communities on floral...

Ecotypic differences in plant growth and anti‐herbivore defence phenotypes are determined by the complex interactions between the abiotic and the biotic environment. Root‐associated microbes (RAMs) are pervasive in nature, vary over climatic gradients and have been shown to influence the expression of multiple plant functional traits related to bio...