Multitrophic interactions and plant growth
Rhizosphere arthropod communities alter plant nutrient supply by consuming and decomposing dead organic material in soil. Indirectly, via soil nutrient pools, this affects plant growth and also interactions of plants with mycorrhizal fungi often associated with plant roots. In previous studies it has been shown that the presence of Collembola results in phenotypic restructuring of root morphology and plant nutrient foraging. This restructuring is likely based on alteration of plant gene expression patterns to optimize plant fitness. Further, by feeding on dead organic matter but also on roots and root associated microorganisms Collembola may induce the expression of plant defence genes. Results of previous studies suggest that these effects propagate into shoots thereby affecting plant secondary metabolism and plant defence against herbivores above the ground. Using two model plants, Arabidopsis thaliana and Quercus petraea, these responses of plants to rhizophere decomposer invertebrates are investigated using tracer experiments with 13C and 15N and transcriptomic-analysis using the NSG technology of the 454 and oligo-arrays completed by qRT-PCR.