Biology subjects

Zimmer, I.

Publications and source records attributed to Zimmer, I..

5 recordsLinked to original sources

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

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↗

bioRxiv2022

Cell wall strengthening by phenylpropanoid dehydrodimers during the plant hypersensitive cell death

Infection of Arabidopsis with avirulent Pseudomonas syringae and exposure to nitrogen dioxide (NO2) both trigger hypersensitive cell death (HCD) that is characterized by the emission of bright blue-green (BG) autofluorescence under UV illumination. The aim of our current work was to identify the BG fluorescent molecules and scrutinize their biosynthesis and functions during the HCD. Compared to wild-type (WT) plants, the phenylpropanoid-deficient mutant fah1 developed normal HCD except for the absence of BG fluorescence. Ultrahigh resolution metabolomics combined with mass difference network analysis revealed that WT but not fah1 plants rapidly accumulate dehydrodimers of sinapic acid, sinapoylmalate, 5-OH-ferulic acid, and 5-OH-feruloylmalate during the HCD. FAH1-dependent BG fluorescence appeared exclusively within dying cells of the upper epidermis as detected by microscopy. Saponification released dehydrodimers from extracted cell wall material. Collectively, our data suggest that HCD induction leads to the formation of free BG fluorescent dehydrodimers from monomeric sinapates and 5-hydroxyferulates. Reactive oxygen species from de-regulated photosynthesis likely contribute to the radical-radical coupling. The formed dehydrodimers move from upper epidermis cells into the apoplast where they esterify and thereby cross-link cell wall polymers. Both, free as well as wall-bound phenylpropanoid dehydrodimers are defense-related compounds in Arabidopsis. We propose that other plants also employ dehydrodimers of highly abundant phenylpropanoids for rapid defense against pathogen attack.

plant biology↗