Project Details
Projekt
Role of chemodiversity in Tanacetum vulgare in interactions with phloem sap feeders and herbivory-pollination trade-offs
Applicants
Dr. Thomas Dussarrat; Professorin Dr. Caroline Müller
Subject Area
Organismic Interactions, Chemical Ecology and Microbiomes of Plant Systems
Term
since 2020
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 415496540
Within Tanacetum vulgare, an intriguingly high chemodiversity is found. In particular, different chemotypes are discriminated based on their leaf terpenoid profiles. In the first period, our goal was to characterise the relationship between chemotypes, phloem exudate composition and leaf metabolic fingerprints and we studied with P7 the consequences of chemodiversity on plant-aphid interactions. Chemotypes were hardly mirrored in the metabolic composition of phloem exudates. However, they were well distinguishable based on numerous satellite metabolites by LC-MS, while the maternal genotype also showed a pronounced influence on chemodiversity. In a common garden experiment with homogenous plots (same chemotype) and heterogenous plots (different chemotypes), we found indications for associational resistance towards the aphid specialist Uroleucon tanaceti. Macrosiphoniella tanacetaria aphids were affected by both chemotype and plot-type and showed a positive relationship with individual plant chemodiversity. Chemodiversity also influenced the behaviour of pollinators and florivores, as revealed in P6. Moreover, plant responses to herbivory can be chemotype-specific, which may affect pollinators. Yet, the nature and consequences of such trade-offs remain poorly explored, especially regarding the underlying metabolic mechanisms. In a second funding period, our goal is to understand whether and how intraspecific chemodiversity influences herbivory-pollination trade-offs (P5 and P6 will be combined). Therefore, we will first test for correlations between leaf and flower chemodiversity using GC-MS and LC-MS. Second, we will assess the plasticity of flower metabolites in response to herbivory imposed by aphids or florivores and in dependence of leaf chemotype. Multivariate statistics and machine learning analyses will be used to investigate these datasets. Besides, our metabolic data will be used by P10 and provide relevant information about terpenoid inducibility, also studied in P2, P4 and P8. Third, we will evaluate the consequences of the metabolic responses to herbivory on pollinator preferences and plant reproductive traits in controlled greenhouse and natural field conditions. To explore the chemical mechanisms underlying herbivory-pollination trade-offs, untargeted analysis of flower chemicals and modelling will be employed. Finally, artificial crossings will be used to disentangle the influences of chemotype and parental genotype on herbivore and pollinator preferences and herbivore performance. The crossings will be performed in coordination with COR, P8 and P9 to facilitate computational model development of terpenoid evolution and biosynthesis. We will also perform analyses of primary metabolites for the chemodiversity-plasticity experiment, in which we will evaluate responses of plants to drought and herbivory.
DFG Programme
Research Units
