Biology subjects

Schnitzler, J.-P.

Publications and source records attributed to Schnitzler, J.-P..

At least 19 recordsLinked to original sources

bioRxiv2026

GSNOR-dependent nitric oxide homeostasis promotes recovery from repeated climate stress across generations in Arabidopsis thaliana

Climate change exposes plants to recurrent and interacting stresses, yet the extent to which these effects persist across generations, and the mechanisms involved, remain unclear. We propagated Arabidopsis thaliana wild type (WT, Col-0) and nitric oxide homeostasis mutant gsnor1-3 (hereafter, gsnor-ko) for five successive generations. Plants were grown under control, drought, elevated CO2, O3, warm temperature, and combined treatment scenarios for the first three generations (G1-G3), followed by two recovery generations under control conditions (G4-G5). We quantified rosette growth, photosynthetic traits, seed production, and transcriptome dynamics by RNA-seq. Across environments, gsnor-ko showed reduced vegetative growth and reproductive output relative to WT. Transcriptomic responses were strongly scenario- and generation-dependent, with the largest differential expression shifts observed under warm-climate and combined-treatment conditions. Compared with WT, gsnor-ko displayed broader gene overlap across generations and stronger retention or reconfiguration of stress-responsive states after stress withdrawal. Functional enrichment and candidate-gene analyses identified pathways/components linked to DNA methylation, heterochromatin maintenance, histone ubiquitination, m6A RNA regulation, and methyl-donor metabolism. Together, these results support a model in which GSNOR activity promotes transcriptomic recovery after repeated climate stress, whereas impaired GSNOR function shifts responses toward multi-generational persistence and epigenetically associated regulatory reconfiguration. HighlightGSNOR-dependent nitric oxide homeostasis promotes transcriptomic resetting after repeated climate stress, whereas impaired NO homeostasis favours multigenerational persistence and chromatin- and RNA-linked regulatory reconfiguration. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=118 SRC="FIGDIR/small/742973v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@6031c6org.highwire.dtl.DTLVardef@163be5borg.highwire.dtl.DTLVardef@1665e9eorg.highwire.dtl.DTLVardef@1cde833_HPS_FORMAT_FIGEXP M_FIG C_FIG

plant biology↗

bioRxiv2026

A recent domestication event in Penicillium biforme, independent of the emblematic cheese mold P. camemberti

Domestication of molds for cheese production has repeatedly shaped Penicillium fungi, most notably giving rise to the emblematic P. camemberti lineage, derived from P. biforme. Here, we identified a new P. biforme lineage, named cheesy, likely selected from P. biforme for food fermentation, including cheese and sausage production. This lineage exhibits evidence of a severe bottleneck, with little nucleotide polymorphism and a single mating type. The cheesy lineage has evolved advantageous traits for cheesemaking: compared to other P. biforme strains and its wild relative P. fuscoglaucum, it displays faster growth on cheese, galactose and lactose media, higher sporulation and germination rates on cheese, elevated lipolytic activity, enhanced inhibition capacities, and produced specific volatile organic compounds. Additionally, P. camemberti and P. biforme cheesy differ in their content of Starship mobile elements, acquired through horizontal transfers. These elements carry cargo genes potentially relevant for adaptation to cheese. Notably, the cheesy lineage has acquired a 20 kb Starship element (Rattus), nested within a much larger 160 kb Starship (Bilge), and carrying cargo genes with predicted functions involved in antagonistic interactions among micro-organisms. SignificanceO_LIWe identified a new Penicillium biforme lineage, named cheesy, which was likely selected from P. biforme for food fermentation (cheese and sausage), genetically and phenotypically different from the emblematic P. camemberti lineage. This lineage suffered from a severe bottleneck, displaying very little nucleotide polymorphism and a single mating type. C_LIO_LIThis newly identified lineage has evolved advantageous traits for cheesemaking; compared to other P. biforme strains and its wild relative P. fuscoglaucum, it displayed faster growth on cheese, galactose and lactose media, higher sporulation and germination rates on cheese, higher lipolytic activity, better inhibition capacities and specific volatile organic compounds. C_LIO_LIPenicillium camemberti and P. biforme cheesy also differed by their content in Starship mobile elements, acquired through horizontal transfers, and carrying cargo genes potentially relevant for adaptation to cheese. C_LIO_LINotably, the cheesy lineage has acquired a specific 20 kb Starship nested within a much larger 160 kb Starship, and likely involved in antagonistic interactions. C_LI

evolutionary biology↗

bioRxiv2026

Geographic and Climatic Origins Shape the Leaf Metabolome of Populus trichocarpa

O_LIBackground and Aims: Chemodiversity is a fitness-relevant trait shaped by genetics, environment, and their interaction. Populus trichocarpa naturally inhabits broad climatic gradients and shows extensive variation in specialised metabolism. We investigated whether provenance and climate of origin imprint leaf chemodiversity and class-level relationships under common-garden conditions, and how these patterns relate to gene expression. C_LIO_LIMethods: Leaves from 87 P. trichocarpa genotypes representing 22 provenances from the west coast of North America growing in a common garden were profiled by untargeted FT-ICR-MS (1030 features) and targeted LC-MS/MS. A subset of 41 genotypes was subject to RNA-seq analyses. We tested whether provenance influenced multivariate patterns and whether metabolomic differences were related to geographic and climatic distance, where chemodiversity was quantified as Functional Hill Diversity. C_LIO_LIKey Results: P. trichocarpa metabolomes differed among origins despite shared growth conditions and showed distance-decay with both geography and climate. North-south extremes were well separated, and within-drainage samples shared high similarity. Flavonoid and isoprenoid pools strongly co-varied across individuals, whereas isoprene synthase activity did not predict total isoprenoids. Transcriptomes showed within-pathway coherence but limited overall provenance separation. C_LIO_LIConclusions: Leaf chemistry in P. trichocarpa retains signatures of geographic origin even under common-garden conditions. Coordinated investment in flavonoids and isoprenoids, together with among-origin differences in functional chemodiversity, reveals provenance-linked chemical fingerprints that complement genomic and metabolic trait data for climate-informed deployment. C_LI

plant biology↗

bioRxiv2026

Integrated phenomic and transcriptomic analyses unveil superior drought plasticity of North African durum wheat landraces

Drought is a major constraint on the productivity of durum wheat across Mediterranean and North African regions. To elucidate the mechanisms underlying drought resilience, we employed a combination of scenario-controlled phenomics and flag leaf transcriptomics across ten durum wheat genotypes. These included the Tunisian landraces Chili and Mahmoudi, seven breeding lines, and the reference cultivar Svevo. The plants were grown to maturity under well-watered or long-term drought conditions in pots and rhizotrons, enabling a comprehensive assessment of growth, yield components, root architecture, physiological traits, and reaction norm plasticity. Drought markedly reduced performance, yet Chili and Mahmoudi consistently maintained superior biomass, grain number and intrinsic water use efficiency (iWUE). This was supported by balanced C/N allocation, strong osmotic adjustment, and the ability to sustain robust root systems under stress, albeit through partly divergent physiological strategies. Transcriptomic profiling revealed highly genotype specific responses, with drought tolerance unrelated to the number of differentially expressed genes. Instead, the landraces displayed distinct regulatory programs involving mainly photosynthesis protection, ABA-related transporters, osmotic adjustment pathways, and stress-responsive transcription factors. These mechanistic insights identify actionable physiological and molecular determinants of drought plasticity and provide high value targets for accelerating the breeding of climate resilient durum wheat. HighlightsIntegrated phenomics and transcriptomics revealed landrace-specific physiological and molecular mechanisms enabling superior drought resilience and identifying actionable targets for durum wheat improvement.

plant biology↗

bioRxiv2026

Common, species-specific, and accession-specific responses of foliar phytohormones and morphological traits to drought and herbivory

BackgroundPlants are exposed to various environmental challenges. With ongoing climate change, droughts and insect outbreaks are expected to become more frequent. Thus, a better understanding is needed of how different plant species respond to such single and combined challenges. This study investigated common versus species-specific responses to environmental challenges in three perennial plant species of different growth forms and whether responses differ intraspecifically among accessions. Clones of different accessions of the herbaceous species Tanacetum vulgare, the woody vine Solanum dulcamara, and the tree Populus nigra were subjected to similar control, herbivory, drought, and combined (drought and herbivory) treatments for the same periods. After the exposure, concentrations of foliar phytohormones and various morphological traits were measured. ResultsAcross all species, several foliar phytohormones and one of ten morphological traits responded consistently to the environmental challenges. Jasmonoyl-isoleucine was induced by herbivory and the combined treatment, abscisic acid (ABA) by drought and the combined treatment, and indole acetic acid by the combined treatment in all species. Root mass remained unchanged in all species. However, structural equation models (SEMs) revealed a shared regulatory pathway across species in which ABA connected treatment and root mass, indicating a common hormonal response potentially linking challenges to growth responses. Despite these common patterns, species-specific responses were pronounced. In P. nigra, a unique induction of salicylic acid was found under the combined treatment, while aboveground mass and root-shoot ratio remained unaffected by any treatment, in contrast to the other two species. Species-specific SEMs further indicated distinct phytohormone-mediated pathways underlying morphological variation. Phenotypic plasticity reflected these species-specific patterns, with none of the phytohormones or morphological traits exhibiting uniform plasticity across species. Intraspecific variation further shaped responses, as phytohormone and morphological trait plasticity depended on accession, indicating substantial accession-specific plant responses. ConclusionsOur results indicate that some responses to comparable challenges may be conserved across species, while others are species-specific. The combined treatment elicited the most pronounced responses, and such complex responses may become more frequent under current global change. Our study highlights that comprehensive understanding of plant responses requires systematic comparisons at both interspecific and intraspecific scales.

ecology↗

bioRxiv2026

Dryland soil rewetting induces strong VOC emissions with potential to form ozone and aerosols

Biogenic volatile organic compounds (VOCs) significantly influence atmospheric chemistry, yet the importance of microbial VOC emissions remains understudied. We investigate petrichor VOC emissions, the characteristic scent following rainfall after prolonged drought, in an aridity gradient across Israel, by simulating soil rewetting events. Rewetting triggered strong VOC fluxes (1-3.5 nmol m-2 s-1 ground area) dominated by sesquiterpenes and benzenoids, with emission patterns linked to climatic regions, soil aridity, and microbial community composition. Petrichor consisted of a complex bouquet of 58 VOCs, and the initial VOC burst resembled the CO2 pulse of the Birch effect. Petrichor emissions showed ozone and secondary organic aerosol formation potentials comparable in magnitude to those estimated for anthropogenic VOC sources in Israel. Despite compositional differences, emissions were of similar magnitudes across the aridity gradient. Given that drylands cover nearly half of Earths terrestrial surface and are expanding, these episodic microbial VOC emissions may represent a significant, previously overlooked source of reactive carbon with potential implications for regional and global atmospheric chemistry.

microbiology↗

bioRxiv2026

Fungal volatiles drive lifestyle-dependent, systemic metabolic reprogramming in poplar

O_LIRationale: Although trees encounter diverse fungal communities, it is unclear how they adjust their physiology in response to fungal ecological strategies before physical contact. We tested whether volatile organic compounds (VOCs) emitted by fungi are sufficient to induce systemic, lifestyle-consistent metabolic states in poplar roots and leaves. C_LIO_LIMethods: Populus x canescens roots were exposed to VOCs from a pathogen (Heterobasidion annosum), a saprotroph (Postia placenta) or an ectomycorrhizal mutualist (Laccaria bicolor) for six weeks in a contact-free pot-in-pot system. Untargeted LC-MS metabolomics characterized VOC-induced metabolic reprogramming in roots and leaves. C_LIO_LIKey results: Fungal VOC exposure alone reconfigured the metabolomes of roots and leaves, with strong discrimination between treatments despite belowground exposure. Poplar revealed a shared VOC-responsive component, but also fungus-specific programmes: pathogen VOCs produced a suppression-dominated systemic phenotype; saprotroph VOCs promoted lipid-centred metabolic activation; and mutualist VOCs elicited restrained, compatibility-consistent shifts with targeted pathway modulation. C_LIO_LIMain conclusion: Volatile-mediated surveillance allows trees to anticipate fungal lifestyle-associated cues and adjust systemic metabolism before physical contact occurs. This links airborne fungal cues to whole-plant physiological configuration and extends plant-fungal recognition beyond contact-dependent mechanisms. C_LI One-sentence summaryVolatile-mediated surveillance allows trees to anticipate fungal lifestyle and adjust systemic metabolism before physical contact occurs.

plant biology↗

bioRxiv2025

Provenance Legacies Override Species Effects in Shaping Oak Rhizosphere Microbiomes and Metabolomes

As climate change drives more frequent and intense drought-heat extremes, selecting drought-tolerant trees is crucial for future forest resilience. However, the role of tree-microbial associations for this key trait remains largely unclear. In this study, we investigated how geographic origin, species identity, and intrinsic water-use efficiency (iWUE) shape the rhizosphere microbiome and root-rhizosphere metabolome of pedunculate (Quercus robur) and sessile (Q. petraea) oaks. In a six-year common garden experiment, we analyzed trees from both species, each grown from seeds from two distinct geographic origins, the upper Rhine basin (URB) and the north-east German lowlands (NGL), differing in water availability, using 16S and ITS rRNA gene based metabarcoding and untargeted metabolomics. We found a consistent legacy effect of seed origin on the composition of the prokaryotic rhizosphere microbiome and the metabolome, whereas tree species had no significant impact. The bacterial family Pseudonocardiaceae was enriched at trees from the drier origin NGL, while Blastocatellaceae and Micromonosporaceae were positively associated with iWUE across samples. Higher iWUE was furthermore significantly correlated with lower prokaryotic diversity and shifts in {beta}-diversity, thereby linking a drought-adaptive host trait to the assembly of the belowground environment. Ellagic acid, a plant derived polyphenol associated with drought tolerance, was enriched in the drier origin NGL and linked to several prokaryotic taxa in correlation networks. The rhizosphere fungal community, however, was largely unaffected by origin or species. Solely fungal community evenness declined with increasing iWUE. Together, our findings suggest that ecotypic adaptation linked to origin can outweigh the effect of species-level traits in shaping the oak rhizosphere microbiome and metabolome. These findings emphasize that provenance-driven ecotypic adaptation can strongly influence plant-microbe interactions and underscore the need for provenance-aware selection and microbiome-informed assisted migration as strategies to strengthen forest drought resilience under global climate change.

ecology↗

bioRxiv2025

Compartmentalized above- and belowground defenses in Tanacetum vulgare are tailored to localized antagonists

Specialized metabolites, specially terpenoids, play a key role in plant defense. However, how terpenoid diversity governs inducible chemistry and root architectural development remain poorly understood. We used a combination of high-throughput root phenotyping and targeted metabolite profiling to examine three leaf terpenoid chemotypes of common tansy (Tanacetum vulgare). Using a phenotyping platform, we tested whether (i) root-chewing wireworms induce root terpenoids locally and alter shoot terpenoids systemically, (ii) phloem-feeding aphids elicit chemotype-dependent responses, and (iii) chemotypes differ in root-system development. After root establishment, the plants were exposed to wireworms (Agriotes spp.) and aphids (Macrosiphoniella tanacetaria), both separately and together, and were then monitored for 60 days. The chemotypes differed in inducible chemistry and root architecture. Chemotype 1 developed the fastest-growing root systems and the highest root:shoot ratios. Wireworms increased stored root sesquiterpenoid levels by more than twofold in chemotypes 1 and 2, whereas chemotype 3 was largely unresponsive. Aphids didn t alter root terpenoids, but significantly increased leaf monoterpenoid emissions in chemotype 1 without affecting stored pools. Therefore, storage and emission were decoupled and depended on both organ and chemotype. Our analysis reveals a compartmentalized, chemotype-specific defense strategy in tansy, highlighting the coordinated regulation of the root system and inducible chemistry. HighlightIn Tanacetum vulgare, wireworms boost root sesquiterpenoids and aphids elevate leaf monoterpenoid emissions; chemotype governs terpenoid defense and root system architecture.

plant biology↗

bioRxiv2025

Eavesdropping roots: Fagus sylvatica detects belowground stress signals from conspecific and heterospecific (Picea abies) neighbors, triggering increased shoot VOC emissions

O_LIVolatile organic compounds (VOCs) facilitate aboveground plant communication, but belowground signaling remains less understood. C_LIO_LIThis study explored root-root interactions between Picea abies and Fagus sylvatica saplings in monospecific (Fagus-Fagus) and heterospecific (Picea-Fagus) pairs (n=6), excluding shoot-level VOC communication. Sender plants were treated with jasmonic acid to simulate herbivory and labeled with 13CO2 and 15NH4NO3 to trace nutrient transfer in a split-root design. VOC emissions and gas exchange were measured over ten days using PTR-TOF-MS and 13CO2-spectroscopy and 13C and 15N were analyzed in roots and shoots via EA-IRMS. C_LIO_LIOur findings reveal, that (i) JA treatment induced strong de novo terpenoid emissions from P. abies and enhanced emissions of oxygenated VOCs and benzenoids from F. sylvatica, (ii) F. sylvatica receiver plants responded similarly to JA-treated neighbors, indicating belowground signaling, and (iii) responses of receiver plants were more pronounced in the heterospecific treatment. Furthermore, formic acid emissions from soils increased following JA treatment, suggesting altered soil microbial activity. Isotopic analysis revealed C exudation into the rhizosphere and N transfer to receiver plants. C_LIO_LIThese results suggest that belowground signaling enables early priming of herbivore-induced defenses in neighboring plants, and that the response intensity is modulated by species identity. C_LI

plant biology↗

bioRxiv2025

DNA methylome responses to biotic and abiotic stress in Arabidopsis thaliana: A multi-study analysis

Plants have evolved complex physiological and morphological strategies to cope with biotic and abiotic stress. At the molecular level, these responses are partly mediated by epigenetic mechanisms such as DNA methylation. In Arabidopsis thaliana, numerous studies have examined stress-induced changes in DNA methylation, aiming to elucidate their roles in stress acclimation. However, comparing these studies remains difficult due to variations in analytical methods and focus. To address this, we conducted an integrative analysis of 13 studies (16 datasets) using a unified bioinformatic pipeline to identify common and stress-specific methylation responses. Our results show that the number and distribution of differentially methylated regions (DMRs) vary by stress type and methylation context CG, CHG, and CHH. CG DMRs were primarily located in gene bodies, while CHG and CHH DMRs were enriched in transposable elements (TEs). Gene Ontology analysis revealed consistently enriched stress-related terms across conditions, indicating shared epigenetic regulation. As TEs have been proposed to act as stress sensors and regulators of nearby gene expression, we examined gene-proximal TEs in more detail. We found significant enrichment of stress-responsive methylation changes in LINE/L1, RathE1_ons, and DNA/HAT elements. While stress-induced methylation is often considered transient, many affected CG DMRs overlapped with loci known to accumulate stable epimutations over generations, suggesting that stress may contribute to long-term heritable epigenetic variation. These findings enhance our understanding of epigenetic regulation in plant stress responses, highlighting both shared and stress-specific methylation dynamics. Significance statementWe combined 16 Arabidopsis thaliana Whole-Genome Bisulfite Sequencing datasets to reveal common and stress-specific DNA methylation responses. Although global methylation levels remained stable, specific DMRs varied according to the type of stress and genomics context. Gene Ontology analysis revealed shared stress pathways. Gene-proximal transposable elements (TEs) (e.g. LINE/L1, RathE1_ons, DNA/HAT) were enriched for stress-responsive methylation changes. Notably, a subset of stress-induced CG DMRs overlap with epimutation-prone loci, suggesting an environmental route toward stable, heritable epigenetic variation.

plant biology↗

bioRxiv2025

Volatile cues from pathogenic, mutualistic and saprotrophic fungi cause specific, fungus-dependent responses in poplar

Plants are exposed to complex interactions with belowground organisms, yet how they differentiate between mutualistic and pathogenic fungi before physical contact remains largely unknown. We exposed the roots of young Populus x canescens to volatile organic compounds (VOCs) emitted by either a pathogenic (Heterobasidion annosum), a saprotrophic (Postia placenta), or an ectomycorrhizal (Laccaria bicolor) fungus. VOC analysis of the shared rhizosphere headspace and leaf emissions revealed that poplar plants could perceive and respond to fungal identity solely through airborne cues. The root-zone headspace contained fungus-specific sesquiterpene fingerprints that remained similar after three and six weeks of co-cultivation: Pathogen-derived VOCs induced constant high sesquiterpene emissions from the root-zone, whereas mycorrhiza caused low but targeted emissions of specific sesquiterpenes. In contrast, saprotrophic VOCs caused a temporal shift in root-zone VOC pattern, with increased sesquiterpene emissions after six weeks. Fungal VOC exposure also altered leaf VOC emissions, enriching alkanes, esters and monoterpenes. Initially, leaf VOC emissions were fungal lifestyle-specific but they converged over time, indicating systemic signal integration of belowground signals. These findings demonstrate that trees can discriminate "friend-versus-foe" through VOCs alone, extending pattern-recognition theory beyond contact-dependent cues. Multivariate analyses suggested organ-specific chemical strategies: roots function as chemosensors decoding fungal volatilomes, while systemic adjustments shape aboveground VOC profiles. Understanding the plant response to fungal VOCs may offer potential for developing early pathogen diagnostics and further elucidate the volatile-mediated plant-fungal interactions.

plant biology↗

bioRxiv2025

Aphid colony size is affected by plant chemotype and terpenoid mixture evenness in tansy

Plants are hosts for above- and belowground insect communities that can influence each other via above-belowground plant-physiological dynamics. To mediate interactions, plants produce secondary metabolites, including terpenoids, and mixtures can differ intraspecifically. While intraspecific variation in plant chemistry gained increased interest, the extent to which intraspecific differences in plant chemistry mediate above-belowground interactions of herbivores remains unclear. We used a full factorial design with six distinct terpenoid chemotypes, differing in their chemical diversity of tansy (Tanacetum vulgare). We exposed these to the aboveground herbivore Macrosiphoniella tanacetaria (Hemiptera: Aphididae), the belowground herbivore Agriotes sp. (Coleoptera: Elateridae), no herbivore or both herbivores, to determine if chemotypes or the chemical diversity of plant compounds affected aphid performance and if the chemical profile mediated the interactions between herbivores. We found that aphid colony size differed between chemotypes, with the strongest colony increase over time in a mixed-mixtures chemotype, and the weakest in a {beta}-thujone chemotype. Root herbivory had no effect on aphid colony size and this did not differ between chemotypes. Aphid colony size was positively correlated with terpenoid evenness, but not with other diversity components. Tansy chemotypes differed in their morphological responses to aboveground herbivory, whereas belowground herbivory exerted minimal impacts. Overall, our results show that intraspecific variation in terpenoid profiles directly and indirectly modify ecological interactions on a plant, with plant chemistry mediating aphid performance and chemotypes differing in their morphological responses to herbivory.

ecology↗

bioRxiv2025

Volatile-Mediated Plant Defense Networks: Field Evidence for Isoprene as a Short-Distance Immune Signal

Isoprene, the most abundant hydrocarbon emitted by vegetation, protects photosynthesis against oxidative and thermal stress and significantly impacts atmospheric chemistry. While laboratory studies suggest a role for isoprene in plant defense, its function in plant-plant communication under natural conditions remains unclear. Here, we demonstrate that isoprene acts as a signaling molecule, triggering systemic immune responses in neighboring plants against bacterial pathogens under field conditions. We established an experimental system using wild-type and transgenic silver birch (Betula pendula) lines engineered to emit varying levels of isoprene. Over two growing seasons, we examined the effects of birch-emitted volatile organic compounds on neighboring Arabidopsis thaliana, including wild-type and immune signaling mutants (llp1: legume lectin-like protein 1; jar1: jasmonate resistant 1). Isoprene emission rates positively correlated with systemic resistance in receiver plants, with higher emissions enhancing inhibition of Pseudomonas syringae growth. This immune response occurred independently of jasmonate signaling but required functional LLP1, suggesting a specific recognition pathway. By combining Arabidopsis mutant responses with birch volatile profiles, we confirmed that isoprene, rather than other terpenoids, mediates this effect. These findings reveal an unrecognized ecological function of isoprene as an airborne immune signal, establishing transgenic birch as a robust model for studying volatile-mediated plant defense networks in natural environments. Our results provide new insights into the molecular mechanisms underlying plant volatile perception and expand our understanding of chemical communication in terrestrial ecosystems. Significance StatementIsoprene, the most abundant volatile organic compound released by plants, protects against abiotic stress. Here, we demonstrate that isoprene also functions under ambient atmosphere as a short-distance immune signal, enhancing neighboring plants resistance to bacterial pathogens. This finding reveals a putative ecological role of isoprene in plant defense networks and suggests strategies for sustainable agriculture and forest management under environmental stress.

plant biology↗

bioRxiv2024

Multiomics plasticity in seed traits of pan-genome wheat cultivars

The molecular basis of cultivar-level variations in polyploid wheat that enables environmental adaptation while maintaining yield and quality in polyploid wheat remains poorly understood. We conducted a detailed phenotypic assessment and multiomics analysis of nine pan-genome polyploid wheat cultivars grown under control and drought conditions. We aimed to investigate the subgenome-level variations, cultivar differences and biochemical mechanisms affecting plant fitness under moderate drought stress. Intrinsic water use efficiency, grain yield, and grain protein content and quality differed among cultivars, supporting the plasticity of drought stress responses. Biased proteome and metabolome abundance changes in response to moderate drought stress during the vegetative stage indicate different strategies for the utilization of homeologous protein isoforms assigned to the A, B, and D subgenomes. Drought effects were detected at the protein level, but significant changes were observed in central carbon pathway metabolites and micronutrient profiles. The subgenomic localization of seed storage proteins highlight differences in nutrient reservoir accumulation and emphasizes the enhanced role of S-rich prolamins in the stress response. Subgenomic variations define cultivar phenotypes by producing molecules that accumulate and enable the underlying trade-offs between environmental adaptation and yield- or quality-related traits. These variations can be used to select crops with increased stress resistance without compromising yield.

plant biology↗

bioRxiv2024

Deciphering plant-beneficial fungal interactions: Unravelling metabolic diversity that underpins communication between Laccaria bicolor and Trichoderma

With over 250 known species, the genus Trichoderma (Ascomycota, Hypocreaceae) is found in various soils, on plant surfaces and as plant endophytes. While Trichoderma species are known as mycoparasites, their antagonistic behaviour can also negatively affect other beneficial fungi, such as mycorrhizal fungi. To gain insight into the metabolic signals involved in the interactions between the ectomycorrhizal fungus (ECM) Laccaria bicolor (Basidomycota, Hydnangiaceae), and different mycoparasitic Trichoderma spp. (T. harzianum strains WM24a1, MS8a1 and ES8g1, and T. atrobrunneum), we performed in vitro dual-confrontation experiments. We studied the volatile organic compounds (VOCs), hyphal metabolomes and soluble metabolites released by each of the fungi in various co-cultivation scenarios. The results revealed an altered growth of the mycelia depending on the degree of contact: When Trichoderma spp. and L. bicolor shared only the same headspace, Trichoderma spp. growth was at least partially inhibited, whereas in direct contact the growth of L. bicolor was impaired. Distinct strain- and species-specific changes in hyphal metabolites, in exudates and volatile emission were revealed from each of the studied fungi. We identified both core metabolite profiles and interaction-specific metabolic responses that were related to carbohydrate, lipid, nucleotide, energy and amino acid metabolisms. Volatile and soluble metabolites revealed temporal and spatial adjustments in dual cultures compared to solitary cultures, suggesting rapid contact-dependent adaptations and demonstrating the dynamic communication mechanisms between Trichoderma spp. and the ECM. These results suggest a central role for both emitted and secreted fungal metabolites in the fungal non-self-recognition and in interaction with each other.

microbiology↗

bioRxiv2024

Date palm acclimates to aridity by diverting organic osmolytes for root osmotic adjustment in parallel with leaf membrane remodeling and ROS scavenging

Highlight statementOsmotic strength of date palm roots increases with soil desiccation, for which the accumulation of organic osmolytes, such as sugars, is essential in complement to energetically cheap mineral osmotics. Date palm (Phoenix dactylifera L.) is an important crop in arid regions that is well-adapted to desert ecosystems. To understand the remarkable ability to grow and yield in water-limited environments, experiments were conducted in a simulated desert environment with water-withholding for up to four weeks. In response to drought, root, rather than leaf, osmotic strength increased, with sugars contributing more to the osmolyte increase than minerals. Consistently, carbon and amino acid metabolism was acclimated toward biosynthesis at both the transcriptional and translational levels. In leaves, a remodeling of membrane systems was observed, suggesting changes in thylakoid lipid composition, which together with the restructuring of the photosynthetic apparatus, indicated an acclimation preventing oxidative damage. Thus, xerophilic date palm avoids oxidative damage under drought by combined prevention and rapid detoxification of oxygen radicals. Although minerals were expected to serve as cheap key osmotics, date palm also relies on organic osmolytes for osmotic adjustment of the roots during desiccation. The diversion of these resources away from growth is consistent with date palms strategy of generally slow growth in harsh environments and clearly indicates a trade-off between growth and stress-related physiological responses.

plant biology↗

bioRxiv2024

Exogenous stimulation of Tanacetum vulgare roots with pipecolic acid leads to tissue-specific responses in terpenoid composition

Tanacetum vulgare L., known as tansy, is a perennial plant with a highly variable terpenoid composition, with mono- and sesquiterpenoids being the most abundant. The high diversity of terpenoids is known to play an important role in mediating ecological interactions. However, the distribution of terpenoids in different tissues and the inducibility of terpenoids in these tissues by biotic stress are poorly understood. In this study, we investigated the changes in terpenoid profiles and concentrations in different plant organs following treatment of roots with pipecolic acid (Pip). Pipecolic acid is a non-proteinogenic amino acid that triggers defense responses in plants. It is often used to induce systemic resistance (SAR) in plants under controlled conditions. Examination of the tissues showed that the leaves and midribs contained mainly monoterpenoids, while the coarse and fine roots of the plants contained mainly sesquiterpenoids. The rhizomes occupied an intermediate position by presenting the terpenoid profiles of both the midribs and roots but also the unique compounds of its own. Treatment with pipecolic acid led to an increase in the concentration of mono- and sesquiterpenoids in all tissues except rhizomes. However, a significantly higher amount of sesquiterpenoids was formed in root tissues in response to Pip compared to shoots. The metabolic atlas for terpenoids presented here shows that there is an exceptionally strong differentiation of terpenoid patterns and terpenoid contents in the different tissues of tansy. This, together with the differential inducibility by biotic stress, suggests that the chemical diversity of terpenoids may play an important role in the ecological interactions of tansy and in the defense against biotic stressors that feed on the below- and above-ground organs of the plant.

ecology↗