Variation in root secondary metabolites is shaped by past climatic conditions

Abstract

12 1. Plants can adapt to changing environments by adjusting the production and 13 maintenance of diverse sets of bioactive secondary metabolites. To date, the impact 14 of past climatic conditions relative to other factors such as soil abiotic factors and 15 herbivore pressure on the evolution of plant secondary metabolites is poorly 16 understood, especially for plant roots.17 2. We explored associations between root latex secondary metabolites in 63 Taraxacum 18 officinale populations across Switzerland and past climatic conditions, soil abiotic 19 parameters, and root herbivore pressure. To assess the contribution of environmental 20 effects, root secondary metabolites were measured in F0 plants in nature and F2 plants 21 under controlled greenhouse conditions.22 3. Concentrations of root latex secondary metabolites were most strongly associated with 23 past climatic conditions, while current soil abiotic factors or root herbivore pressure did 24 not show a clear association with root latex chemistry. Results were identical for natural 25 and controlled conditions, suggesting heritable trait variation rather than environmental 26 plasticity as underlying factor.27 4. Synthesis. We conclude that climatic conditions likely play a major role in the evolution 28 of root secondary metabolites. Direct abiotic effects are likely underlying this pattern, 29 hinting at a novel role of root latex metabolites the tolerance of abiotic stress.30 31

Heritable variation in root secondary metabolites is associated with recent climate

“…We furthermore retrieved climatic conditions of the different habitats over the last 20 years and performed model selection to determine which environmental variables are most strongly associated with naturally expressed and heritable variation in root secondary metabolites. A previous version of this work has been placed on a preprint server (Bont, Züst, Huber, & Erb, 2020).…”