Ecological convergence of secondary phytochemicals along elevational gradients.

Bakhtiari M; Glauser G; Defossez E; Rasmann S

doi:10.1111/nph.16966

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Journal article

Ecological convergence of secondary phytochemicals along elevational gradients.

Bakhtiari M Institute of Biology, University of Neuchâtel, Rue-Emile Argand 11, Neuchâtel, 2000, Switzerland.
Glauser G Neuchâtel Platform of Analytical Chemistry (NPAC), Avenue de Bellevaux 51, Neuchâtel, 2000, Switzerland.
Defossez E Institute of Biology, University of Neuchâtel, Rue-Emile Argand 11, Neuchâtel, 2000, Switzerland.
Rasmann S Institute of Biology, University of Neuchâtel, Rue-Emile Argand 11, Neuchâtel, 2000, Switzerland.

2020-09-27

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The New phytologist. - 2020

plant growth-defence syndromes

specialist versus generalist herbivores

English Biologists still strive to identify the ecological and evolutionary drivers of phytochemical variation that mediate biotic interactions. We hypothesized that plant species growing at sites characterized by high herbivore pressure would converge to produce highly toxic blends of secondary metabolites, independent of phylogenetic constraints. To address the role of shared evolutionary history and ecological niches in driving variation in plant phytochemistry, we combined targeted metabolomics with insect herbivore bioassays and with a set of growth-related traits of several Cardamine species growing along the entire elevational gradient of the Alps. We observed that Cardamine phytochemical profiles grouped according to previously established growth form categorizations within specific abiotic conditions, independently of phylogenetic relationship. We also showed that novel indices summarizing functional phytochemical diversity better explain plant resistance against chewing and sap-feeding herbivores than classic diversity indices. We conclude that multiple functional axes of phytochemical diversity should be integrated with the functional axis of plant growth forms to study phenotypic convergence along large-scale ecological gradients.

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