Plant Chemodiversity Research Articles

Influences of plant maternal effects, chemotype, and environment on the leaf bacterial community.

Plant individuals within a species can differ markedly in their leaf chemical composition, forming so-called chemotypes. Little is known about whether such differences impact the microbial communities associated with leaves and how different environmental conditions may shape these relationships. We used Tanacetum vulgare as a model plant to study the impacts of maternal effects, leaf terpenoid chemotype, and the environment on the leaf bacterial community by growing plant clones in the field and a greenhouse. We hypothesized that all three factors affect the bacterial community of the leaves and that terpenoid and bacterial profiles as well as chemodiversity and microbial diversity are correlated. The results revealed that the leaf microbial community was significantly influenced by plant maternal effects and environmental conditions (field vs. greenhouse), but not by the leaf terpenoid profile. There was also no evidence for a correlation between terpenoid profiles and bacterial community composition and diversity. Overall, a higher number of unique amplicon sequence variants were found in the leaves of clones grown under field conditions than in those grown in the greenhouse. We also identified interactions between individual terpenoids and specific members of the leaf bacterial community. Our study suggests that terpenoid chemodiversity has, overall, little effect on the leaf bacterial community, but some terpenoids might affect specific beneficial species. While more studies are needed to investigate the relationship between plant chemodiversity and plant microbiomes, our results highlight the importance of integrating plant maternal effects, chemodiversity, and environment in understanding plant-microbiome interactions.

Intraspecific plant chemodiversity at the individual and plot levels influences flower visitor groups with consequences for germination success

Abstract Chemodiversity, the diversity of specialised (secondary) metabolites, plays a crucial role in mediating interactions between plants and animals, including insect herbivores and mutualists. Chemodiversity can be observed at both the individual and the population level. However, the impacts of chemodiversity at these two levels on interactions between plants and floral visitors, mainly pollinators and floral herbivores (florivores), are only poorly understood. This study aimed to investigate the effects of chemodiversity at both individual (chemotype) and plot level on pollinators and florivores, examining their mutual interactions. To investigate these questions, we used individuals of the perennial Tanacetum vulgare differing in their terpenoid composition, representing different chemotypes. We planted individuals of five distinct chemotypes in a common garden design with homogeneous (five plants of the same chemotype) and heterogeneous (five different chemotypes) plots and observed flower visits in dependence of individual chemotype and plot type. Seeds were collected from a subset of plants and germination rates determined. Our findings revealed that chemodiversity at the plot level significantly influenced pollinator visitation, with more visits on plants of heterogeneous plots. We also observed marginally more pollinators on one of the chemotypes grown in homogeneous plots. In contrast, chemotype but not plot type had a significant effect on florivore visits. Pollinator and florivore species richness did not vary with plot type. Furthermore, a negative correlation was observed between pollinator and florivore visits in 1 year. Germination rates were positively correlated with pollinator visits and affected by chemotype but not by florivore visits or plot type. Synthesis. Our study emphasises the significance of the spatial level at which plant chemistry is perceived by flower visitors, potentially influencing the germination success of plants. Exploring the ecology of these visitors and the varying selection pressures they exert on floral chemistry can help to elucidate the evolutionary processes that maintain chemodiversity in natural environments. Read the free Plain Language Summary for this article on the Journal blog.

Understanding the chemodiversity of plants: Quantification, variation and ecological function

AbstractPlants produce a great number of phytochemicals serving a variety of different functions. Recently, the chemodiversity of these compounds (i.e., the diversity of compounds produced by a plant) has been suggested to be an important aspect of the plant phenotype that may shape interactions between plants, their environment, and other organisms. However, we lack an agreement on how to quantify chemodiversity, which complicates conclusions about the functional importance of it. Here, we discuss how chemodiversity (deconstructed into components of richness, evenness and disparity) may relate to different ecologically relevant aspects of the phenotype. Then, we systematically review the literature on chemodiversity to examine methodological practices, explore patterns of variability in diversity across different levels of biological organization, and investigate the functional role of this diversity in interactions between plants and other organisms. Overall, the reviewed literature suggests that high chemodiversity is often beneficial for plants, although a heterogeneity of methodological approaches partly limits what general conclusions can be drawn. Importantly, to support future research on this topic, we provide a framework with a decision tree facilitating choices on which measures of chemodiversity are best used in different contexts and outline key questions and avenues for future research. A more thorough understanding of chemodiversity will provide insights into its evolution and functional role in ecological interactions between plants and their environment.

Intraspecific chemical variation of Tanacetum vulgare affects plant growth and reproductive traits in field plant communities.

The study investigated the impact of intraspecific plant chemodiversity on plant growth and reproductive traits at both the plant and plot levels. It also aimed to understand how chemodiversity at stand level affects ecosystem functioning and plant-plant interactions. We describe a biodiversity experiment in which we manipulated intraspecific plant chemodiversity at the plot level using six different chemotypes of common tansy (Tanacetum vulgare L., Asteraceae). We tested the effects of chemotype identity and plot-level chemotype richness on plant growth and reproductive traits and plot-level headspace emissions. The study found that plant chemotypes differed in growth and reproductive traits and that traits were affected by the chemotype richness of the plots. Although morphological differences among chemotypes became less pronounced over time, reproductive phenology patterns persisted. Plot-level trait means were also affected by the presence or absence of certain chemotypes in a plot, and the direction of the effect depended on the specific chemotype. However, chemotype richness did not lead to overyielding effects. Lastly, chemotype blends released from plant communities were neither richer nor more diverse with increasing plot-level chemotype richness, but became more dissimilar as they became more dissimilar in their leaf terpenoid profiles. We found that intraspecific plant chemodiversity is crucial in plant-plant interactions. We also found that the effects of chemodiversity on plant growth and reproductive traits were complex and varied depending on the chemotype richness of the plots. This long-term field experiment will allow further investigation into plant-insect interactions and insect community assembly in response to intraspecific chemodiversity.

The evolution of chemodiversity in plants-From verbal to quantitative models.

Plants harbour a great chemodiversity, that is diversity of specialised metabolites (SMs), at different scales. For instance, individuals can produce a large number of SMs, and populations can differ in their metabolite composition. Given the ecological and economic importance of plant chemodiversity, it is important to understand how it arises and is maintained over evolutionary time. For other dimensions of biodiversity, that is species diversity and genetic diversity, quantitative models play an important role in addressing such questions. Here, we provide a synthesis of existing hypotheses and quantitative models, that is mathematical models and computer simulations, for the evolution of plant chemodiversity. We describe each model's ingredients, that is the biological processes that shape chemodiversity, the scales it considers and whether it has been formalized as a quantitative model. Although we identify several quantitative models, not all are dynamic and many influential models have remained verbal. To fill these gaps, we outline our vision for the future of chemodiversity modelling. We identify quantitative models used for genetic variation that may be adapted for chemodiversity, and we present a flexible framework for the creation of individual-based models that address different scales of chemodiversity and combine different ingredients that bring this chemodiversity about.

The advent of plant cells in bioreactors.

Ever since agriculture started, plants have been bred to obtain better yields, better fruits, or sustainable products under uncertain biotic and abiotic conditions. However, a new way to obtain products from plant cells emerged with the development of recombinant DNA technologies. This led to the possibility of producing exogenous molecules in plants. Furthermore, plant chemodiversity has been the main source of pharmacological molecules, opening a field of plant biotechnology directed to produce high quality plant metabolites. The need for different products by the pharma, cosmetics agriculture and food industry has pushed again to develop new procedures. These include cell production in bioreactors. While plant tissue and cell culture are an established technology, beginning over a hundred years ago, plant cell cultures have shown little impact in biotechnology projects, compared to bacterial, yeasts or animal cells. In this review we address the different types of bioreactors that are currently used for plant cell production and their usage for quality biomolecule production. We make an overview of Nicotiana tabacum, Nicotiana benthamiana, Oryza sativa, Daucus carota, Vitis vinifera and Physcomitrium patens as well-established models for plant cell culture, and some species used to obtain important metabolites, with an insight into the type of bioreactor and production protocols.

A combination of Polypodium leucotomos extract with vitamin A, vitamin C and selenium as an immune adjuvant against recurrent infections

ABSTRACT Plant chemodiversity is a helpful tool for disease prevention and a basis for adjuvant treatments to conventional therapies. In this regard, the extract of Polypodium leucotomos rhizomes, PLE, has shown benefits fighting inflammation and recurrent infections but its molecular mechanism is poorly undersood. This work shows that Plesinox 3A, containing PLE, Vitamins A, C, and selenium, helps modulate the initial inflammatory response triggered by bacterial LPS through the upregulation of IL8 and IL10, together with downregulation of COX2, IL1B and TNF, in a more efficient manner than PLE alone. Additionally, this formulation enhances the antiviral response through the upregulation of MX1, IFNA1 and IFNG in different cell types. Finally, the addition of vitamins and selenium to PLE in Plesinox 3A greatly boosts the anti-bacterial properties of PLE alone. Overall, these findings support the combined use of PLE, vitamins, and selenium, in the form of Plesinox 3A as an immune booster to prevent recurrent infections, highlighting a gene set potentially involved in its beneficial effect, as well as showing its direct anti-bacterial properties, which are greater than those of PLE alone.

Influences of chemotype and parental genotype on metabolic fingerprints of tansy plants uncovered by predictive metabolomics

Intraspecific plant chemodiversity shapes plant-environment interactions. Within species, chemotypes can be defined according to variation in dominant specialised metabolites belonging to certain classes. Different ecological functions could be assigned to these distinct chemotypes. However, the roles of other metabolic variation and the parental origin (or genotype) of the chemotypes remain poorly explored. Here, we first compared the capacity of terpenoid profiles and metabolic fingerprints to distinguish five chemotypes of common tansy (Tanacetum vulgare) and depict metabolic differences. Metabolic fingerprints captured higher variation in metabolites while preserving the ability to define chemotypes. These differences might influence plant performance and interactions with the environment. Next, to characterise the influence of the maternal origin on chemodiversity, we performed variation partitioning and generalised linear modelling. Our findings revealed that maternal origin was a higher source of chemical variation than chemotype. Predictive metabolomics unveiled 184 markers predicting maternal origin with 89% accuracy. These markers included, among others, phenolics, whose functions in plant-environment interactions are well established. Hence, these findings place parental genotype at the forefront of intraspecific chemodiversity. We recommend considering this factor when comparing the ecology of various chemotypes. Additionally, the combined inclusion of inherited variation in main terpenoids and other metabolites in computational models may help connect chemodiversity and evolutionary principles.

Extending the elemental defence hypothesis in the light of plant chemodiversity.

Some plant species tolerate and accumulate high levels of metals or metalloids in their tissues. The elemental defence hypothesis posits that metal(loid) hyperaccumulation by these plants can serve as protection against antagonists. Numerous studies support this hypothesis. In addition, as other plant species, hyperaccumulators synthesise specialised metabolites that can act as organic defences. In principle, the composition and concentration of plant-specialised metabolites vary pronouncedly not only among species, but also within species and within individuals. This variation is called chemodiversity. Surprisingly, the role of chemodiversity has received little attention in elemental defence. Thus, we advocate that the concept of the elemental defence hypothesis should be extended and linked to the multifunctionality of plant chemodiversity to better understand the eco-evolutionary dynamics and maintenance of metal(loid) hyperaccumulation. Comprehensive literature studies revealed that both metal(loid)s and specialised metabolites acting as defences are highly diverse in some hyperaccumulators and the biosynthetic pathways of these two types of defences are partly intertwined. Several edaphic-, population-, temporal- and spatial-related factors were found to influence metal(loid) diversity, which should be considered in the elemental defence hypothesis. We thus present a novel synthesis and outlook to extend the elemental defence hypothesis in the light of chemodiversity.

Cytochrome b 5: A versatile electron carrier and regulator for plant metabolism.

Cytochrome b5 (CB5) is a small heme-binding protein, known as an electron donor delivering reducing power to the terminal enzymes involved in oxidative reactions. In plants, the CB5 protein family is substantially expanded both in its isoform numbers and cellular functions, compared to its yeast and mammalian counterparts. As an electron carrier, plant CB5 proteins function not only in fatty acid desaturation, hydroxylation and elongation, but also in the formation of specialized metabolites such as flavonoids, phenolic esters, and heteropolymer lignin. Furthermore, plant CB5s are found to interact with different non-catalytic proteins such as ethylene signaling regulator, cell death inhibitor, and sugar transporters, implicating their versatile regulatory roles in coordinating different metabolic and cellular processes, presumably in respect to the cellular redox status and/or carbon availability. Compared to the plentiful studies on biochemistry and cellular functions of mammalian CB5 proteins, the cellular and metabolic roles of plant CB5 proteins have received far less attention. This article summarizes the fragmentary information pertaining to the discovery of plant CB5 proteins, and discusses the conventional and peculiar functions that plant CB5s might play in different metabolic and cellular processes. Gaining comprehensive insight into the biological functions of CB5 proteins could offer effective biotechnological solutions to tailor plant chemodiversity and cellular responses to environment stimuli.

Secure and Sustainable Sourcing of Plant Tissues for the Exhaustive Exploration of Their Chemodiversity.

The main challenge of plant chemical diversity exploration is how to develop tools to study exhaustively plant tissues. Their sustainable sourcing is a limitation as bioguided strategies and dereplication need quite large amounts of plant material. We examine if alternative solutions could overcome these difficulties by obtaining a secure, sustainable, and scalable source of tissues able to biosynthesize an array of metabolites. As this approach would be as independent of the botanical origin as possible, we chose eight plant species from different families. We applied a four steps culture establishment procedure, monitoring targeted compounds through mass spectrometry-based analytical methods. We also characterized the capacities of leaf explants in culture to produce diverse secondary metabolites. In vitro cultures were successfully established for six species with leaf explants still producing a diversity of compounds after the culture establishment procedure. Furthermore, explants from leaves of axenic plantlets were also analyzed. The detection of marker compounds was confirmed after six days in culture for all tested species. Our results show that the first stage of this approach aiming at easing exploration of plant chemodiversity was completed, and leaf tissues could offer an interesting alternative providing a constant source of natural compounds.

The chloroalkaloid (\u2212)-acutumine is biosynthesized via a Fe(II)- and 2-oxoglutarate-dependent halogenase in Menispermaceae plants

Plant halogenated natural products are rare and harbor various interesting bioactivities, yet the biochemical basis for the involved halogenation chemistry is unknown. While a handful of Fe(II)- and 2-oxoglutarate-dependent halogenases (2ODHs) have been found to catalyze regioselective halogenation of unactivated C–H bonds in bacteria, they remain uncharacterized in the plant kingdom. Here, we report the discovery of dechloroacutumine halogenase (DAH) from Menispermaceae plants known to produce the tetracyclic chloroalkaloid (−)-acutumine. DAH is a 2ODH of plant origin and catalyzes the terminal chlorination step in the biosynthesis of (−)-acutumine. Phylogenetic analyses reveal that DAH evolved independently in Menispermaceae plants and in bacteria, illustrating an exemplary case of parallel evolution in specialized metabolism across domains of life. We show that at the presence of azide anion, DAH also exhibits promiscuous azidation activity against dechloroacutumine. This study opens avenues for expanding plant chemodiversity through halogenation and azidation biochemistry.

Ecology and Evolution of Intraspecific Chemodiversity of Plants

An extraordinarily high intraspecific chemical diversity, i.e. chemodiversity, has been found in several plant species, of which some are of major ecological or economic relevance. Moreover, even within an individual plant there is substantial chemodiversity among tissues and across seasons. This chemodiversity likely has pronounced ecological effects on plant mutualists and antagonists, associated foodwebs and, ultimately, biodiversity. Surprisingly, studies on interactions between plants and their herbivores or pollinators often neglect plant chemistry as a level of diversity and phenotypic variation. The main aim of this Research Unit (RU) is to understand the emergence and maintenance of intraspecific chemodiversity in plants. We address the following central questions: 1) How does plant chemodiversity vary across levels, i.e., within individuals, among individuals within populations, and among populations? 2) What are the ecological consequences of intraspecific plant chemodiversity? 3) How is plant chemodiversity genetically determined and maintained? By combining field and laboratory studies with metabolomics, transcriptomics, genetic tools, statistical data analysis and modelling, we aim to understand causes and consequences of plant chemodiversity and elucidate its impacts on the interactions of plants with their biotic environment. Furthermore, we want to identify general principles, which hold across different species, and develop meaningful measures to describe the fascinating diversity of defence chemicals in plants. These tasks require integrated scientific collaboration of experts in experimental and theoretical ecology, including chemical and molecular ecology, (bio)chemistry and evolution.

Metabolic diversification of nitrogen-containing metabolites by the expression of a heterologous lysine decarboxylase gene in Arabidopsis.

SummaryLysine decarboxylase converts l‐lysine to cadaverine as a branching point for the biosynthesis of plant Lys‐derived alkaloids. Although cadaverine contributes towards the biosynthesis of Lys‐derived alkaloids, its catabolism, including metabolic intermediates and the enzymes involved, is not known. Here, we generated transgenic Arabidopsis lines by expressing an exogenous lysine/ornithine decarboxylase gene from Lupinus angustifolius (La‐L/ODC) and identified cadaverine‐derived metabolites as the products of the emerged biosynthetic pathway. Through untargeted metabolic profiling, we observed the upregulation of polyamine metabolism, phenylpropanoid biosynthesis and the biosynthesis of several Lys‐derived alkaloids in the transgenic lines. Moreover, we found several cadaverine‐derived metabolites specifically detected in the transgenic lines compared with the non‐transformed control. Among these, three specific metabolites were identified and confirmed as 5‐aminopentanal, 5‐aminopentanoate and δ‐valerolactam. Cadaverine catabolism in a representative transgenic line (DC29) was traced by feeding stable isotope‐labeled [α‐15N]‐ or [ε‐15N]‐l‐lysine. Our results show similar 15N incorporation ratios from both isotopomers for the specific metabolite features identified, indicating that these metabolites were synthesized via the symmetric structure of cadaverine. We propose biosynthetic pathways for the metabolites on the basis of metabolite chemistry and enzymes known or identified through catalyzing specific biochemical reactions in this study. Our study shows that this pool of enzymes with promiscuous activities is the driving force for metabolite diversification in plants. Thus, this study not only provides valuable information for understanding the catabolic mechanism of cadaverine but also demonstrates that cadaverine accumulation is one of the factors to expand plant chemodiversity, which may lead to the emergence of Lys‐derived alkaloid biosynthesis.

Evolutionary Developments in Plant Specialized Metabolism, Exemplified by Two Transferase Families.

Plant specialized metabolism emerged from the land colonization by ancient plants, becoming diversified along with plant evolution. To date, more than 1 million metabolites have been predicted to exist in the plant kingdom, and their metabolic processes have been revealed on the molecular level. Previous studies have reported that rates of evolution are greater for genes involved in plant specialized metabolism than in primary metabolism. This perspective introduces topics on the enigmatic molecular evolution of some plant specialized metabolic processes. Two transferase families, BAHD acyltransferases and aromatic prenyltransferases, which are involved in the biosynthesis of paclitaxel and meroterpenes, respectively, have shown apparent expansion. The latter family has been shown to beinvolved in the biosynthesis of a variety of aromatic substances, including prenylated coumarins in citrus plants and shikonin in Lithospermum erythrorhizon. These genes have evolved in the development of each special subfamily within the plant lineage. The broadness of substrate specificity and the exon-intron structure of their genes may provide hints to explain the evolutionary process underlying chemodiversity in plants.

Medicinal and Aromatic Plant Research in the 21st Century

It has been estimated that 250,000 terrestrial plants contribute to biodiversity on earth. The chemodiversity of plants, however, may be considered to be much larger due to the vast number of phytochemical constituents with their wide range of bioactivity as seen in medicinal and aromatic plants. The present review focuses on the potential of medicinal and aromatic plants for medicinal, nutritional and other purposes, but highlights also possible toxicities. Quality control for standardization of herbal products as well as advancements in molecular biological techniques will foster the progress of medicinal and aromatic plant research in the years to come.

Elicitation, a New Window into Plant Chemodiversity and Phytochemical Drug Discovery.

Elicitation, a New Window into Plant Chemodiversity and Phytochemical Drug Discovery.

Elicitation, a new window into plant chemodiversity and phytochemical drug discovery.

Plant extracts collected from the wild are important sources for drug discovery. However, these extracts suffer from a lack of reproducible bioactivity and chemical composition caused by the highly inducible, variable, and transitory nature of plant secondary metabolism. Here, we demonstrate that exposing roots of hydroponically grown plants to chemical elicitors selectively and reproducibly induced the production of bioactive compounds, dramatically increased the hit rate, and more than doubled the number of plant species showing in vitro activity against bacteria, fungi, or cancer. Elicitation performed under controlled conditions dramatically improves reliability and efficiency of plant extracts in drug discovery while preserving wild species and their habitats.