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Abstract Plants produce an astonishingly diverse array of specialized metabolites. A crucial step in understanding the origin of such chemodiversity is describing how chemodiversity manifests across the spatial and ontogenetic scales relevant to plant–biotic interactions.Focusing on 21 sympatric species ofPsychotriaandPalicourea sensu lato(Rubiaceae), we describe patterns of specialized metabolite diversity across spatial and ontogenetic scales using a combination of field collections, untargeted metabolomics, and ecoinformatics. We compare α, β, and γ diversity of specialized metabolites in expanding leaves, unripe pulp, immature seed, ripe pulp, mature seed, and fine roots.Within species, fruit tissues from across ontogenetic stages had ≥α diversity than leaves, and ≤β diversity than leaves. Pooled across species, fruit tissues and ontogenetic stages had the highest γ diversity of all organs, and fruit tissues and ontogenetic stages combined had a higher incidence of organ‐specific mass spectral features than leaves. Roots had ≤α diversity than leaves and the lowest β and γ diversity of all organs. Phylogenetic correlations of chemical distance varied by plant organ and chemical class.Our results describe patterns of specialized metabolite diversity across organs and species and provide support for organ‐specific contributions to plant chemodiversity. This study contributes to the growing understanding within plant evolutionary ecology of the biological scales of specialized metabolite diversification. Future studies combining our data on specialized metabolite diversity with biotic interaction data and experiments can test existing hypotheses on the roles of ecological interactions in the evolution of chemodiversity.
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Compartmentalization of specialized metabolites across vegetative and reproductive tissues in two sympatric Psychotria species
Abstract Premise The specialized metabolites of plants are recognized as key chemical traits in mediating the ecology and evolution of sundry plant–biotic interactions, from pollination to seed predation. Intra‐ and interspecific patterns of specialized metabolite diversity have been studied extensively in leaves, but the diverse biotic interactions that contribute to specialized metabolite diversity encompass all plant organs. Focusing on two species of Psychotria shrubs, we investigated and compared patterns of specialized metabolite diversity in leaves and fruit with respect to each organ's diversity of biotic interactions. Methods To evaluate associations between biotic interaction diversity and specialized metabolite diversity, we combined UPLC‐MS metabolomic analysis of foliar and fruit specialized metabolites with existing surveys of leaf‐ and fruit‐centered biotic interactions. We compared patterns of specialized metabolite richness and variance among vegetative and reproductive tissues, among plants, and between species. Results In our study system, leaves interact with a far larger number of consumer species than do fruit, while fruit‐centric interactions are more ecologically diverse in that they involve antagonistic and mutualistic consumers. This aspect of fruit‐centric interactions was reflected in specialized metabolite richness—leaves contained more than fruit, while each organ contained over 200 organ‐specific specialized metabolites. Within each species, leaf‐ and fruit‐specialized metabolite composition varied independently of one another across individual plants. Contrasts in specialized metabolite composition were stronger between organs than between species. Conclusions As ecologically disparate plant organs with organ‐specific specialized metabolite traits, leaves and fruit can each contribute to the tremendous overall diversity of plant specialized metabolites.
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- Award ID(s):
- 1953934
- PAR ID:
- 10441135
- Date Published:
- Journal Name:
- American Journal of Botany
- Volume:
- 110
- Issue:
- 7
- ISSN:
- 0002-9122
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1002/ajb2.16191
