In our research group, we study how plants adapt to environmental stresses, particularly to herbivory. We combine high-throughput sequencing approaches with experimental evolution, metabolic profiling, and genetic manipulation to elucidate the genetic, epigenetic, and physiological bases of plant adaptation using duckweeds as a model system. Furthermore, we use the acquired methods to transform duckweeds into a green biofactories to produce high-value metabolites in plants. Through these studies, we will improve our conceptual understanding of plant defense and explore potential industrial applications.
Toxic secondary metabolites are of central importance to protect plants against herbivores. Many toxins are stored as precursors, so called protoxins, and are activated by compartmentalized enzymes upon tissue disruption. Curiously, protoxins are not always activated by plant-derived enzymes: in many cases, they seem to be cleaved by digestive enzymes from the herbivores. To date, the genetic basis of this phenomenon as well as its ecological implications are not well understood. To shed light into these aspects, we are studying the metabolization of taraxinic acid β-D-glucopyranosyl ester (TA-G), a sesquiterpene of the common dandelion (Taraxacum officinale) that repels its major root herbivore, the common cockchafer larva (Melolontha melolontha). Using a combination of heterologous expression and RNA interference, we aim to identify the genetic basis of TA-G deglycosylation during M. melolontha feeding, which will allow us to elucidate the ecological consequences of this phenomenon. This project will thereby assess the importance of the insect digestive system in mediating plant-herbivore interactions.
DNA methylation is hypothesized to mediate transgenerational plasticity across asexual plant generations. Yet, experimental evidence for this hypothesis is scarce. Using the giant duckweed, one of the world´s fastest reproducing flowering plants, we study how variation in DNA methylation is generated, whether such variation is transmitted across asexual generations, and whether inherited methylome variations alter plant phenotype and stress resistance. Together, these studies will provide evidence whether asexually reproducing plants may resist and adapt to environmental stresses through epigenetic mechanisms.
Duckweeds are rapidly growing, easy to cultivate and edible for both livestock and humans. As such, duckweeds are promising green biofactories to produce economically valuable metabolites. To enhance these applications, we are optimizing tools for genetically manipulating both the nuclear and the plastid genomes of duckweeds. These studies will lay the foundation for transforming duckweeds into efficient green biofactories to produce economically valuable metabolites in an environmentally friendly way.
Meret Huber received her master’s degree in biology from the University of Zürich in 2011. She then moved to the Max Planck Institute for Chemical Ecology in Jena for her PhD, in which she studied how plants defend their roots against herbivorous insects. After a short postdoctoral employment at the Max Planck Institute, she established a junior research group at the University of Münster to elucidate transgenerational stress memory in clonal plants. In 2022, she received funding from the DFG Emmy Noether Programme to study the epigenetic basis of transgenerational stress memory. In 2023, Meret Huber became a professor in plant evolutionary ecology at the University of Mainz. She also serves as a director of the botanical garden of the University of Mainz.
Martina obtained her B.A. in Communication Design from the University of Applied Sciences Mainz in 2017. She then worked at Jack Wolfskin and as a Yoga teacher. Following certification in commercial matters and Human Resources from Wifa Mainz business school in 2023, Martina pursued her current administrative role at the Johannes Gutenberg University.
Manuela worked at Böhringer Ingelheim after her training as TA until she took time off to raise her children.
In her following positon, she gained experience with a wide variety of responsibilities in the microbiology laboratory of a service laboratory for almost 25 years. Since June 2023, she has been supporting AG Huber as a TA.
Martin received his PhD from the University of Jena for his work at the Max-Planck Institute for Chemical Ecology (MPI-ICE, Prof. Ian Baldwin) on the role of growth and development-related phytohormones in plant-herbivore interactions in 2015. He continued working at the MPI-ICE until 2018, then moved to the Institute for Evolution and Biodiversity in Münster, before moving to the Institute of Organismic and Molecular Evolution (IomE) in Mainz in 2022. He has extensive experience in chemical ecology and analytical chemistry, in particular the LC-MS based analysis of small metabolites, and he’s interested in studying the mechanisms and functions behind diverse plant interactions.
Amanda received her PhD in 2018 from the Federal University of Vicosa (Brazil) for her work on Plastid Genomics of several plant species. In 2021, she moved to the Max Planck Institute of Molecular Plant Physiology for her postdoctoral research granted by the Alexander von Humboldt Foundation, in which her research focused on Plastid Biotechnology for the development of a plant-based hyaluronic acid production platform. In April 2023, she worked as a Technology Development Specialist at the Brazilian Center for Research in Energy and Materials where she studied the engineering of yeasts for biofuel production. In November 2023, she joined the Huber group for postdoctoral research focusing on the development of protocols to engineer the nuclear and plastid genomes of duckweed and their biotechnological applications.
Gopal Singh received his PhD in June, 2020 from CSIR-IHBT, Palampur, India for his work on NGS-assisted biosynthetic pathway elucidation of steviol glycosides (SGs), the diterpenoids commercially popular as low calorie natural sweeteners from Stevia rebaudiana. In January, 2021, he moved to Poland to worked as a Post-doctoral researcher at IBCH, PAS, Poznan where he worked in an NCN-funded project on interspecies metabolic engineering of Tryptophan-derived specialized metabolism for their function in plant immunity. Gopal joined the Huber lab in February 2025 to work on his DFG-funded project leveraging giant duckweed (Spirodela polyrhiza) as a potential photosynthetic chassis for sustainable production of valuable plant metabolites.
Alexandra joined the Huber group in October 2020. She is a biologist from the Universidad Peruana Cayetano Heredia, Peru, and received her M.Sc. degree in Evolutionary Biology from the Universidad del Bío-Bío, Chile. Alexandra is interested in explaining the role of non-genetic transgenerational inheritance in clonal evolution. She received her PhD in June 2025 at Huber lab.
Ryan received his PhD from the University of East Anglia (Norwich, UK) where he worked on the behavioural ecology and population genetics of bumblebees. Following this, Ryan switched fields and spent four years at the John Innes Centre (Norwich, UK) exploring crop-pest interactions between rapeseed and the cabbage stem flea beetle, first as a research assistant and then as a postdoctoral researcher. Ryan joined the Huber group in February 2026 to work on the evolutionary ecology of plant-herbivore interactions.
Enrico is a Biotechnology Engineer graduated at the State University of São Paulo, Brazil, in 2022. In August 2023, he completed his a master’s degree in Genetics and Plant Breeding at the University of São Paulo, Brazil.
Enrico started his Ph.D. in the Huber group in September 2023. Throughout his doctoral studies, he will investigate the molecular mechanisms underlying transgenerational epigenetic inheritance in giant duckweed (Spirodela polyrhiza).
Ida is a member of Huber Lab since January 2025. She finished her master’s in biotechnology at the University of Kaiserslautern-Landau in 2024. As a GenEvo associated PhD student she investigates the role of small RNAs in transgenerational plasticity in a clonal plant such as giant duckweed.
Samuel joined the Huber and Baumann labs in January 2025. He recieved his B.Sc from Manchester Metropolitan University in biology in 2023 and his MSc in 2024 from Queen Mary University of London. His thesis project aims to investigate both genetic and epigenetic mutation rates in the New Mexico whiptail lizard, Aspidoscelis neomexicanus, an asexually reproducing vertebrate. He will provide estimates of the frequency of epimutations, and investigate their potential for transgenerational inheritance, and their effects on gene expression.
Vivianne joined the Huber lab in September 2024 to obtain her M.Sc., where she genetically modified the giant duckweed Spirodela polyrhiza to express a novel defense pathway. Since October 2025, she has been building on this foundation in her PhD, exploring the potential of S. polyrhiza as a versatile platform for synthetic biology. Her project focuses on engineering the plant to produce various compounds, such as triacylglycerols, aiming to provide a sustainable alternative to the current environmentally damaging production methods.
- Duckweeds (Lemnaceae) have excellent potential for fundamental and applied research due to ease of cultivation, small size, and continuous fast clonal growth. However, their usage as model organisms and platforms for biotechnological applications is often limited by the lack of universal genetic manipulation methods necessary for transgene expression, gene editing, and other methods to modify gene expression.
- To identify suitable strains for genetic manipulation of the giant duckweed, Spirodela polyrhiza, we screened several genotypes for callus induction and regeneration and established genetic transformation.
- We identified SP162 to be amenable to Agrobacterium-mediated transformation via tissue culture. The procedure is robust and reproducible across laboratories, allowing stable expression of different reporter genes and selectable markers, enabling CRISPR/Cas9-mediated genome editing. In addition, due to a weak small RNA-based silencing response, S. polyrhiza sustains prolonged periods of transgene activity in transient expression assays.
- To promote duckweed research and encourage the adoption of S. polyrhiza, we have made SP162 (ID#: 5676) and its genome publicly available and provide here detailed procedures for its cultivation and transformation. Furthermore, we created a web server to explore its genome, retrieve gene sequences, and implement orthologous gene search and a gRNA design function for diverse CRISPR/Cas-based applications (https://agxu.uni-mainz.de/SP162/).
Laticifers – among the most common defensive reservoirs in plants – are hypothesized to benefit plant fitness by preventing microbes from entering wounds. I argue that while latex seals wounds, and can suppress microbial growth, direct evidence that these processes benefit plant fitness is scarce. I outline a roadmap for filling this knowledge gap.
Latex – a potential plant defense against microbes (cell.com)
- Laticifers are hypothesized to mediate both plant‐herbivore and plant‐microbe interactions. However, there is little evidence for this dual function.
- We investigated whether the major constituent of natural rubber, cis‐1,4‐polyisoprene, a phylogenetically widespread and economically important latex polymer, alters plant resistance and the root microbiome of the Russian dandelion (Taraxacum koksaghyz) under attack of a root herbivore, the larva of the May cockchafer (Melolontha melolontha).
- Rubber‐depleted transgenic plants lost more shoot and root biomass upon herbivory than normal rubber content near‐isogenic lines. M. melolontha preferred to feed on artificial diet supplemented with rubber‐depleted rather than normal rubber content latex. Likewise, adding purified cis‐1,4‐polyisoprene in ecologically relevant concentrations to diet deterred larval feeding and reduced larval weight gain. Metagenomics …
Natural rubber reduces herbivory and alters the microbiome below ground (wiley.com)
Gut enzymes can metabolize plant defense compounds and thereby affect the growth and fitness of insect herbivores. Whether these enzymes also influence feeding preference is largely unknown. We studied the metabolization of taraxinic acid β-D-glucopyranosyl ester (TA-G), a sesquiterpene lactone of the common dandelion (Taraxacum officinale) that deters its major root herbivore, the common cockchafer larva (Melolontha melolontha). We have demonstrated that TA-G is rapidly deglucosylated and conjugated to glutathione in the insect gut. A broad-spectrum M. melolontha β-glucosidase, Mm_bGlc17, is sufficient and necessary for TA-G deglucosylation. Using cross-species RNA interference, we have shown that Mm_bGlc17 reduces TA-G toxicity. Furthermore, Mm_bGlc17 is required for the preference of M. melolontha larvae for TA-G-deficient plants. Thus, herbivore metabolism modulates both the toxicity and deterrence of a plant defense compound. Our work illustrates the multifaceted roles of insect digestive enzymes as mediators of plant-herbivore interactions.
Although non-genetic inheritance is thought to play an important role in plant ecology and evolution, evidence for adaptive transgenerational plasticity is scarce. Here, we investigated the consequences of copper excess on offspring defences and fitness under recurring stress in the duckweed Spirodela polyrhiza across multiple asexual generations. Growing large monoclonal populations (greater than 10 000 individuals) for 30 generations under copper excess had negative fitness effects after short and no fitness effect after prolonged growth under recurring stress. These time-dependent growth rates were likely influenced by environment-induced transgenerational responses, as propagating plants as single descendants for 2 to 10 generations under copper excess had positive, negative or neutral effects on offspring fitness depending on the interval between initial and recurring stress (5 to 15 generations). Fitness benefits under recurring stress were independent of flavonoid accumulations, which in turn were associated with altered plant copper concentrations. Copper excess modified offspring fitness under recurring stress in a genotype-specific manner, and increasing the interval between initial and recurring stress reversed these genotype-specific fitness effects. Taken together, these data demonstrate time- and genotype-dependent adaptive and non-adaptive transgenerational responses under recurring stress, which suggests that non-genetic inheritance alters the evolutionary trajectory of clonal plant lineages in fluctuating environments.
Mutation rate and effective population size (Ne) jointly determine intraspecific genetic diversity, but the role of mutation rate is often ignored. Here we investigate genetic diversity, spontaneous mutation rate and Ne in the giant duckweed (Spirodela polyrhiza). Despite its large census population size, whole-genome sequencing of 68 globally sampled individuals reveals extremely low intraspecific genetic diversity. Assessed under natural conditions, the genome-wide spontaneous mutation rate is at least seven times lower than estimates made for other multicellular eukaryotes, whereas Ne is large. These results demonstrate that low genetic diversity can be associated with large-Ne species, where selection can reduce mutation rates to very low levels. This study also highlights that accurate estimates of mutation rate can help to explain seemingly unexpected patterns of genome-wide variation.
Low genetic variation is associated with low mutation rate in the giant duckweed
Plants produce large amounts of secondary metabolites in their shoots and roots and store them in specialized secretory structures. Although secondary metabolites and their secretory structures are commonly assumed to have a defensive function, evidence that they benefit plant fitness under herbivore attack is scarce, especially below ground. Here, we tested whether latex secondary metabolites produced by the common dandelion (Taraxacum officinale agg.) decrease the performance of its major native insect root herbivore, the larvae of the common cockchafer (Melolontha melolontha), and benefit plant vegetative and reproductive fitness under M. melolontha attack. Across 17 T. officinale genotypes screened by gas and liquid chromatography, latex concentrations of the sesquiterpene lactone taraxinic acid β-D-glucopyranosyl ester (TA-G) were negatively associated with M. melolontha larval growth. Adding purified TA-G to artificial diet at ecologically relevant concentrations reduced larval feeding. Silencing the germacrene A synthase ToGAS1, an enzyme that was identified to catalyze the first committed step of TA-G biosynthesis, resulted in a 90% reduction of TA-G levels and a pronounced increase in M. melolontha feeding. Transgenic, TA-G-deficient lines were preferred by M. melolontha and suffered three times more root biomass reduction than control lines. In a common garden experiment involving over 2,000 T. officinale individuals belonging to 17 different genotypes, high TA-G concentrations were associated with the maintenance of high vegetative and reproductive fitness under M. melolontha attack. Taken together, our study demonstrates that a latex secondary metabolite benefits plants under herbivore attack, a result that provides a mechanistic framework for root herbivore driven natural selection and evolution of plant defenses below ground.
If you are interested in joining the lab but there is no funded project available, please contact Prof. Meret Huber.
There are bachelor and master projects available to study plant-herbivore interactions, transgenerational stress responses and metabolic engineering.
Please send an e-mail to Prof. Meret Huber: meret.huber@uni-mainz.de
Currently no open positions.
Currently no open positions.
Currently no open positions.