Project Details
Projekt
How is chemodiversity in Populus nigra affected by antagonists and, in turn, how does it affect arthropod and microbial species assembly?
Applicant
Professorin Dr. Sybille Unsicker
Subject Area
Organismic Interactions, Chemical Ecology and Microbiomes of Plant Systems
Term
since 2020
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 415496540
Populus nigra is a dioecious tree native to German floodplain forests. It produces a large diversity of volatile organic compounds, especially when attacked by herbivorous insects. In the first funding period, our goal was to investigate the chemodiversity in leaves of different strata of the canopy in male and female P. nigra genotypes. Our results revealed pronounced differences in leaf chemical traits both with respect to the sex of the trees and the height within the tree crown. Chemical traits along the vertical axis within the canopy may differ due to strong heterogeneity of abiotic and biotic factors within the canopy, as well as differences in resource allocation patterns between male and female trees. We are currently testing in a greenhouse experiment whether these height- and sex-specific differences in leaf chemistry observed in mature trees persist under controlled greenhouse conditions in young trees grown from stem cuttings harvested at different heights within mature trees. Further analysis of our data will reveal whether the heterogeneity in leaf chemical traits of mature trees has implications for herbivore damage or infection by fungal pathogens. There is currently insufficient knowledge about how chemodiversity fundamentally affects the assembly of arthropod and microbial species in trees. In a second funding period, my aim is to explore (with P2) seasonal trajectories of chemodiversity in male and female P. nigra trees from three different origins in Germany growing in a common garden. In these trees, I will also investigate the effects of chemodiversity on the assembly of arthropod (with SP7) and microbial species. Certainly, herbivorous insects and pathogenic microbes actively influence chemodiversity in P. nigra by inducing recurrent metabolic changes as a defence response in the trees. How simultaneous infestations with different antagonists affect the chemodiversity of P. nigra is currently poorly understood. Therefore, I will investigate in a controlled greenhouse study how single and combined attacks of antagonists below- and aboveground affect the chemodiversity of different organs in P. nigra to better understand the divergence in phytochemical profiles under field conditions. We will compare organ-specific chemodiversity across all plant species (P2-P7). The metabolic data from this study will be used by P9 (virtual Populus) and by P10 and provide relevant information about terpenoid inducibility studied in P4, P5 and P8. In the joint chemodiversity-plasticity experiment (COR), we will evaluate the response of chemically divergent P. nigra genotypes to drought and herbivory.
DFG Programme
Research Units
