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Kempthorne CJ, St Pierre M, Le A, Livingstone S, McNulty J, Cadotte MW, Liscombe DK. Mass spectrometry-based metabolomics for the elucidation of alkaloid biosynthesis and function in invasive Vincetoxicum rossicum populations. PHYTOCHEMISTRY 2024; 221:114051. [PMID: 38452878 DOI: 10.1016/j.phytochem.2024.114051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 02/23/2024] [Accepted: 03/02/2024] [Indexed: 03/09/2024]
Abstract
The genus Vincetoxicum includes a couple of highly invasive vines in North America that threaten biodiversity and challenge land management strategies. Vincetoxicum species are known to produce bioactive phenanthroindolizidine alkaloids that might play a role in the invasiveness of these plants via chemical interactions with other organisms. Untargeted, high-resolution mass spectrometry-based metabolomics approaches were used to explore specialized metabolism in Vincetoxicum plants collected from invaded sites in Ontario, Canada. All metabolites corresponding to alkaloids in lab and field samples of V. rossicum and V. nigrum were identified, which collectively contained 25 different alkaloidal features. The biosynthesis of these alkaloids was investigated by the incorporation of the stable isotope-labelled phenylalanine precursor providing a basis for an updated biosynthetic pathway accounting for the rapid generation of chemical diversity in invasive Vincetoxicum. Aqueous extracts of aerial Vincetoxicum rossicum foliage had phytotoxic activity against seedlings of several species, resulting in identification of tylophorine as a phytotoxin; tylophorine and 14 other alkaloids from Vincetoxicum accumulated in soils associated with full-sun and a high-density of V. rossicum. Using desorption-electrospray ionization mass spectrometry, 15 alkaloids were found to accumulate at wounded sites of V. rossicum leaves, a chemical cocktail that would be encountered by feeding herbivores. Understanding the specialized metabolism of V. rossicum provides insight into the roles and influences of phenanthroindolizidine alkaloids in ecological systems and enables potential, natural product-based approaches for the control of invasive Vincetoxicum and other weedy species.
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Affiliation(s)
- Christine J Kempthorne
- Vineland Research and Innovation Centre, 4890 Victoria Ave North, Box 4000, Vineland Station, Ontario, L0R 2E0, Canada; Centre for Biotechnology, Brock University, 1812 Sir Isaac Brock Way, St Catharines, Ontario, L2S 3A1, Canada
| | - Max St Pierre
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main St W, Hamilton, Ontario, L8S 4L8, Canada
| | - Andrew Le
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario, M1C 1A4, Canada
| | - Stuart Livingstone
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario, M1C 1A4, Canada
| | - James McNulty
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main St W, Hamilton, Ontario, L8S 4L8, Canada
| | - Marc W Cadotte
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario, M1C 1A4, Canada
| | - David K Liscombe
- Vineland Research and Innovation Centre, 4890 Victoria Ave North, Box 4000, Vineland Station, Ontario, L0R 2E0, Canada; Department of Biological Sciences, Brock University, 1812 Sir Isaac Brock Way, St Catharines, Ontario, L2S 3A1, Canada.
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2
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Wang X, He Y, Sedio BE, Jin L, Ge X, Glomglieng S, Cao M, Yang J, Swenson NG, Yang J. Phytochemical diversity impacts herbivory in a tropical rainforest tree community. Ecol Lett 2023; 26:1898-1910. [PMID: 37776563 DOI: 10.1111/ele.14308] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 07/24/2023] [Accepted: 08/25/2023] [Indexed: 10/02/2023]
Abstract
Metabolomics provides an unprecedented window into diverse plant secondary metabolites that represent a potentially critical niche dimension in tropical forests underlying species coexistence. Here, we used untargeted metabolomics to evaluate chemical composition of 358 tree species and its relationship with phylogeny and variation in light environment, soil nutrients, and insect herbivore leaf damage in a tropical rainforest plot. We report no phylogenetic signal in most compound classes, indicating rapid diversification in tree metabolomes. We found that locally co-occurring species were more chemically dissimilar than random and that local chemical dispersion and metabolite diversity were associated with lower herbivory, especially that of specialist insect herbivores. Our results highlight the role of secondary metabolites in mediating plant-herbivore interactions and their potential to facilitate niche differentiation in a manner that contributes to species coexistence. Furthermore, our findings suggest that specialist herbivore pressure is an important mechanism promoting phytochemical diversity in tropical forests.
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Affiliation(s)
- Xuezhao Wang
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, China
- University of Chinese Academy of Sciences, Beijing, China
- School of Ecology and Environment, Southwest Forestry University, Kunming, China
| | - Yunyun He
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Brian E Sedio
- Department of Integrative Biology, University of Texas at Austin, Texas, Austin, USA
- Smithsonian Tropical Research Institute, Ancón, Republic of Panama
| | - Lu Jin
- College of Life Sciences, South China Agricultural University, Guangzhou, China
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Xuejun Ge
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Suphanee Glomglieng
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Min Cao
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, China
| | - Jianhong Yang
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Nathan G Swenson
- Department of Biological Sciences, University of Notre Dame, Indiana, Notre Dame, USA
| | - Jie Yang
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, China
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3
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Sun X, Sun Y, Cao X, Zhai X, Callaway RM, Wan J, Flory SL, Huang W, Ding J. Trade-offs in non-native plant herbivore defences enhance performance. Ecol Lett 2023; 26:1584-1596. [PMID: 37387416 DOI: 10.1111/ele.14283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 05/25/2023] [Accepted: 05/29/2023] [Indexed: 07/01/2023]
Abstract
Non-native plants are typically released from specialist enemies but continue to be attacked by generalists, albeit at lower intensities. This reduced herbivory may lead to less investment in constitutive defences and greater investment in induced defences, potentially reducing defence costs. We compared herbivory on 27 non-native and 59 native species in the field and conducted bioassays and chemical analyses on 12 pairs of non-native and native congeners. Non-natives suffered less damage and had weaker constitutive defences, but stronger induced defences than natives. For non-natives, the strength of constitutive defences was correlated with the intensity of herbivory experienced, whereas induced defences showed the reverse. Investment in induced defences correlated positively with growth, suggesting a novel mechanism for the evolution of increased competitive ability. To our knowledge, these are the first linkages reported among trade-offs in plant defences related to the intensity of herbivory, allocation to constitutive versus induced defences, and growth.
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Affiliation(s)
- Xiao Sun
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Yumei Sun
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Xueyao Cao
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Xincong Zhai
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Ragan M Callaway
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
| | - Jinlong Wan
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
| | - S Luke Flory
- Agronomy Department, University of Florida, Gainesville, Florida, USA
| | - Wei Huang
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
| | - Jianqing Ding
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
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4
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Salgado AL, Glassmire AE, Sedio BE, Diaz R, Stout MJ, Čuda J, Pyšek P, Meyerson LA, Cronin JT. Metabolomic Evenness Underlies Intraspecific Differences Among Lineages of a Wetland Grass. J Chem Ecol 2023; 49:437-450. [PMID: 37099216 DOI: 10.1007/s10886-023-01425-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/20/2023] [Accepted: 04/05/2023] [Indexed: 04/27/2023]
Abstract
The metabolome represents an important functional trait likely important to plant invasion success, but we have a limited understanding of whether the entire metabolome or targeted groups of compounds confer an advantage to invasive as compared to native taxa. We conducted a lipidomic and metabolomic analysis of the cosmopolitan wetland grass Phragmites australis. We classified features into metabolic pathways, subclasses, and classes. Subsequently, we used Random Forests to identify informative features to differentiate five phylogeographic and ecologically distinct lineages: European native, North American invasive, North American native, Gulf, and Delta. We found that lineages had unique phytochemical fingerprints, although there was overlap between the North American invasive and North American native lineages. Furthermore, we found that divergence in phytochemical diversity was driven by compound evenness rather than metabolite richness. Interestingly, the North American invasive lineage had greater chemical evenness than the Delta and Gulf lineages but lower evenness than the North American native lineage. Our results suggest that metabolomic evenness may represent a critical functional trait within a plant species. Its role in invasion success, resistance to herbivory, and large-scale die-off events common to this and other plant species remain to be investigated.
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Affiliation(s)
- Ana L Salgado
- Department of Biological Sciences, Louisiana State University, Life Sciences Building, Baton Rouge, LA, 70803, USA.
| | - Andrea E Glassmire
- Department of Biological Sciences, Louisiana State University, Life Sciences Building, Baton Rouge, LA, 70803, USA
| | - Brian E Sedio
- Department of Integrative Biology, University of Texas, Austin, TX, 78712, USA
- Smithsonian Tropical Research Institute, Balboa, Ancón, Apartado, 0843-03092, Republic of Panama
| | - Rodrigo Diaz
- Department of Entomology, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Michael J Stout
- Department of Entomology, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Jan Čuda
- Department of Invasion Ecology, Czech Academy of Sciences, Institute of Botany, Průhonice, Czech Republic
| | - Petr Pyšek
- Department of Invasion Ecology, Czech Academy of Sciences, Institute of Botany, Průhonice, Czech Republic
- Department of Ecology, Faculty of Science, Charles University, Prague, CZ -128 44, Czech Republic
| | - Laura A Meyerson
- Department of Natural Resource Sciences, University of Rhode Island, Kingston, RI, 02881, USA
| | - James T Cronin
- Department of Biological Sciences, Louisiana State University, Life Sciences Building, Baton Rouge, LA, 70803, USA
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5
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Petrén H, Köllner TG, Junker RR. Quantifying chemodiversity considering biochemical and structural properties of compounds with the R package chemodiv. THE NEW PHYTOLOGIST 2023; 237:2478-2492. [PMID: 36527232 DOI: 10.1111/nph.18685] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 12/11/2022] [Indexed: 06/17/2023]
Abstract
Plants produce large numbers of phytochemical compounds affecting plant physiology and interactions with their biotic and abiotic environment. Recently, chemodiversity has attracted considerable attention as an ecologically and evolutionary meaningful way to characterize the phenotype of a mixture of phytochemical compounds. Currently used measures of phytochemical diversity, and related measures of phytochemical dissimilarity, generally do not take structural or biosynthetic properties of compounds into account. Such properties can be indicative of the compounds' function and inform about their biosynthetic (in)dependence, and should therefore be included in calculations of these measures. We introduce the R package chemodiv, which retrieves biochemical and structural properties of compounds from databases and provides functions for calculating and visualizing chemical diversity and dissimilarity for phytochemicals and other types of compounds. Our package enables calculations of diversity that takes the richness, relative abundance and - most importantly - structural and/or biosynthetic dissimilarity of compounds into account. We illustrate the use of the package with examples on simulated and real datasets. By providing the R package chemodiv for quantifying multiple aspects of chemodiversity, we hope to facilitate investigations of how chemodiversity varies across levels of biological organization, and its importance for the ecology and evolution of plants and other organisms.
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Affiliation(s)
- Hampus Petrén
- Evolutionary Ecology of Plants, Department of Biology, Philipps-University Marburg, 35043, Marburg, Germany
| | - Tobias G Köllner
- Department of Natural Product Biosynthesis, Max Planck Institute for Chemical Ecology, 07745, Jena, Germany
| | - Robert R Junker
- Evolutionary Ecology of Plants, Department of Biology, Philipps-University Marburg, 35043, Marburg, Germany
- Department of Environment and Biodiversity, University of Salzburg, 5020, Salzburg, Austria
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6
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Wu S, Chen L, Zhou Y, Xiao F, Liu D, Wang Y. Invasive Plants Have Higher Resistance to Native Generalist Herbivores Than Exotic Noninvasive Congeners. ENVIRONMENTAL ENTOMOLOGY 2023; 52:81-87. [PMID: 36545824 DOI: 10.1093/ee/nvac108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Indexed: 06/17/2023]
Abstract
Research on the invasive plant Phytolacca americana (L.) mostly focuses on its medicinal value and enrichment of heavy metals. However, little is known regarding its impact on native herbivorous insects. In this study, we explored the effects of P. americana and the exotic noninvasive Phytolacca icosandra (L.) on the Spodoptera litura (Fabricius) (native tobacco cutworm) via bioassay, oviposition preference, detoxifying enzyme activity analysis, and phytochemical determination. We found that the oviposition preference index (OPI) of S. litura feeding on P. icosandra was higher than that of P. americana. The developmental duration of S. litura feeding on P. icosandra was shorter than that of P. americana. Additionally, the Acetylcholinesterase (AchE) and Glutathione-S-transferase (GST) activities of S. litura feeding on P. americana were higher than that of S. litura feeding on artificial diets or P. icosandra. The content of lignin and flavonoids in P. americana was relatively high, whereas starch content was relatively low. These findings suggest invasive plants have higher resistance to herbivores, thereby suffering less damage than exotic noninvasive plants.
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Affiliation(s)
- Shan Wu
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming 650500, China
- Centre for Invasion Biology, Institute of Biodiversity, Yunnan University, Kunming 650500, China
| | - Li Chen
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming 650500, China
- Centre for Invasion Biology, Institute of Biodiversity, Yunnan University, Kunming 650500, China
| | - Yue Zhou
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming 650500, China
- Centre for Invasion Biology, Institute of Biodiversity, Yunnan University, Kunming 650500, China
| | - Feng Xiao
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming 650500, China
- Centre for Invasion Biology, Institute of Biodiversity, Yunnan University, Kunming 650500, China
| | - Danfeng Liu
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming 650500, China
- Centre for Invasion Biology, Institute of Biodiversity, Yunnan University, Kunming 650500, China
| | - Yi Wang
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming 650500, China
- Centre for Invasion Biology, Institute of Biodiversity, Yunnan University, Kunming 650500, China
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7
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Morrison JA, Roche B, Veatch‐Blohm M. Woody plant secondary chemicals increase in response to abundant deer and arrival of invasive plants in suburban forests. Ecol Evol 2022; 12:e8814. [PMID: 35432930 PMCID: PMC9006230 DOI: 10.1002/ece3.8814] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 03/11/2022] [Accepted: 03/20/2022] [Indexed: 12/03/2022] Open
Abstract
Plants in suburban forests of eastern North America face the dual stressors of high white-tailed deer density and invasion by nonindigenous plants. Chronic deer herbivory combined with strong competition from invasive plants could alter a plant's stress- and defense-related secondary chemistry, especially for long-lived juvenile trees in the understory, but this has not been studied. We measured foliar total antioxidants, phenolics, and flavonoids in juveniles of two native trees, Fraxinus pennsylvanica (green ash) and Fagus grandifolia (American beech), growing in six forests in the suburban landscape of central New Jersey, USA. The trees grew in experimental plots subjected for 2.5 years to factorial treatments of deer access/exclosure × addition/no addition of the nonindigenous invasive grass Microstegium vimineum (Japanese stiltgrass). As other hypothesized drivers of plant secondary chemistry, we also measured nonstiltgrass herb layer cover, light levels, and water availability. Univariate mixed model analysis of the deer and stiltgrass effects and multivariate structural equation modeling (SEM) of all variables showed that both greater stiltgrass cover and greater deer pressure induced antioxidants, phenolics, and flavonoids, with some variation between species. Deer were generally the stronger factor, and stiltgrass effects were most apparent at high stiltgrass density. SEM also revealed that soil dryness directly increased the chemicals; deer had additional positive, but indirect, effects via influence on the soil; in beech photosynthetically active radiation (PAR) positively affected flavonoids; and herb layer cover had no effect. Juvenile trees' chemical defense/stress responses to deer and invasive plants can be protective, but also could have a physiological cost, with negative consequences for recruitment to the canopy. Ecological implications for species and their communities will depend on costs and benefits of stress/defense chemistry in the specific environmental context, particularly with respect to invasive plant competitiveness, extent of invasion, local deer density, and deer browse preferences.
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Affiliation(s)
| | - Bernadette Roche
- Department of BiologyLoyola University MarylandBaltimoreMarylandUSA
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Jarmusch SA, van der Hooft JJJ, Dorrestein PC, Jarmusch AK. Advancements in capturing and mining mass spectrometry data are transforming natural products research. Nat Prod Rep 2021; 38:2066-2082. [PMID: 34612288 PMCID: PMC8667781 DOI: 10.1039/d1np00040c] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Covering: 2016 up to 2021Mass spectrometry (MS) is an essential technology in natural products research with MS fragmentation (MS/MS) approaches becoming a key tool. Recent advancements in MS yield dense metabolomics datasets which have been, conventionally, used by individual labs for individual projects; however, a shift is brewing. The movement towards open MS data (and other structural characterization data) and accessible data mining tools is emerging in natural products research. Over the past 5 years, this movement has rapidly expanded and evolved with no slowdown in sight; the capabilities of today vastly exceed those of 5 years ago. Herein, we address the analysis of individual datasets, a situation we are calling the '2021 status quo', and the emergent framework to systematically capture sample information (metadata) and perform repository-scale analyses. We evaluate public data deposition, discuss the challenges of working in the repository scale, highlight the challenges of metadata capture and provide illustrative examples of the power of utilizing repository data and the tools that enable it. We conclude that the advancements in MS data collection must be met with advancements in how we utilize data; therefore, we argue that open data and data mining is the next evolution in obtaining the maximum potential in natural products research.
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Affiliation(s)
- Scott A Jarmusch
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 221, DK-2800 Kongens Lyngby, Denmark.
| | | | - Pieter C Dorrestein
- Collaborative Mass Spectrometry Innovation Center, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, 92093-0751, USA
| | - Alan K Jarmusch
- Collaborative Mass Spectrometry Innovation Center, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, 92093-0751, USA
- Immunity, Inflammation, and Disease Laboratory, Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
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9
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Sedio BE, Spasojevic MJ, Myers JA, Wright SJ, Person MD, Chandrasekaran H, Dwenger JH, Prechi ML, López CA, Allen DN, Anderson-Teixeira KJ, Baltzer JL, Bourg NA, Castillo BT, Day NJ, Dewald-Wang E, Dick CW, James TY, Kueneman JG, LaManna J, Lutz JA, McGregor IR, McMahon SM, Parker GG, Parker JD, Vandermeer JH. Chemical Similarity of Co-occurring Trees Decreases With Precipitation and Temperature in North American Forests. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.679638] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Plant diversity varies immensely over large-scale gradients in temperature, precipitation, and seasonality at global and regional scales. This relationship may be driven in part by climatic variation in the relative importance of abiotic and biotic interactions to the diversity and composition of plant communities. In particular, biotic interactions may become stronger and more host specific with increasing precipitation and temperature, resulting in greater plant species richness in wetter and warmer environments. This hypothesis predicts that the many defensive compounds found in plants’ metabolomes should increase in richness and decrease in interspecific similarity with precipitation, temperature, and plant diversity. To test this prediction, we compared patterns of chemical and morphological trait diversity of 140 woody plant species among seven temperate forests in North America representing 16.2°C variation in mean annual temperature (MAT), 2,115 mm variation in mean annual precipitation (MAP), and from 10 to 68 co-occurring species. We used untargeted metabolomics methods based on data generated with liquid chromatography-tandem mass spectrometry to identify, classify, and compare 13,480 unique foliar metabolites and to quantify the metabolomic similarity of species in each community with respect to the whole metabolome and each of five broad classes of metabolites. In addition, we compiled morphological trait data from existing databases and field surveys for three commonly measured traits (specific leaf area [SLA], wood density, and seed mass) for comparison with foliar metabolomes. We found that chemical defense strategies and growth and allocation strategies reflected by these traits largely represented orthogonal axes of variation. In addition, functional dispersion of SLA increased with MAP, whereas functional richness of wood density and seed mass increased with MAT. In contrast, chemical similarity of co-occurring species decreased with both MAT and MAP, and metabolite richness increased with MAT. Variation in metabolite richness among communities was positively correlated with species richness, but variation in mean chemical similarity was not. Our results are consistent with the hypothesis that plant metabolomes play a more important role in community assembly in wetter and warmer climates, even at temperate latitudes, and suggest that metabolomic traits can provide unique insight to studies of trait-based community assembly.
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