Soil biodiversity is of great importance for the maintenance of multifunctionality in terrestrial ecosystems. Due to the complexity of belowground biodiversity, novel insights about the combined... Show moreSoil biodiversity is of great importance for the maintenance of multifunctionality in terrestrial ecosystems. Due to the complexity of belowground biodiversity, novel insights about the combined influences of plant-soil interactions have been rarely empirically examined under realistic field conditions. To cope with this challenge, a soil inoculation approach in a field experiment was conducted to manipulate soil community composition. This thesis aims to shed light on the impacts of plant-soil interactions on the aboveground and belowground processes in primary dune ecosystems examined with the aid of such manipulation. Show less
Soil is a home for an unbelievable diversity and abundance of microbial life that is essential for supporting life on our planet. Microorganisms living in soil take part in cleaning our water,... Show moreSoil is a home for an unbelievable diversity and abundance of microbial life that is essential for supporting life on our planet. Microorganisms living in soil take part in cleaning our water, degrading toxic compounds and recycling nutrients, and last but not least, they are essential partners to plants. Through their roots, plants release a mix of secretions to attract microorganisms, creating a remarkable environment called the rhizosphere. The rhizosphere is populated by microbes who often provide beneficial services to plants, like nutrient acquisition, growth promotion and protection against diseases. Modern agriculture suffers from losses caused by crop diseases, and a common way of controlling diseases is using pesticides. Pesticides often have a negative impact on the environment, and disease-causing agents (pathogens), can become resistant with time. One of the possible solutions to this problem is based on soil microbial communities. Due to the activity of their microbiome, some soils possess a natural capacity to protect plants against diseases. These soils are called disease suppressive soils, and the investigation of the microbial mechanisms leading to the natural protection of crops is the topic of this thesis. In our work we used a common pathogen of cereals, fungus Fusarium culmorum, and wheat, to first, identify suppressive soils able to protect this plant from the pathogen, and, investigate the mechanisms of protection using e.g. sequencing and mass spectrometry. During our project we identified potential microbes, genes and metabolites involved in soil disease suppressiveness. Moreover, we evaluated the impact of microplastic on the soil disease suppressiveness. Show less
By growing in a soil plants change the biotic and abiotic properties of the soil in which they grow. This can influence the performance of plants that grow in the same soil subsequently and is... Show moreBy growing in a soil plants change the biotic and abiotic properties of the soil in which they grow. This can influence the performance of plants that grow in the same soil subsequently and is known as plant soil feedback (PSF). Species largely differ in how they influence the soil while they grow in it and how they react to conditioned soil. So far PSF was mainly shown to influence biomass of plants and certain specific chemical compounds in plants. This thesis demonstrates how the whole metabolome of a range of different plants changes due to different microbiomes in the soil and that the influence of soil on the metabolome of plants can be stronger than the effect of herbivory. Furthermore, this thesis shows how these PSF change over time and on different spatial scales and which methods are most suitable to study the metabolomic response of plants. Show less
In this thesis, the role of plant-mediated soil legacy effects in shaping aboveground plant-insect interactions was investigated. This work shows that soil legacy effects on plant-insect... Show moreIn this thesis, the role of plant-mediated soil legacy effects in shaping aboveground plant-insect interactions was investigated. This work shows that soil legacy effects on plant-insect interactions are a common phenomenon in nature, both in individual responding plant species and their associated herbivores, as well as in responding plant communities and associated herbivores. This thesis elucidates two potential mechanisms how soils can influence aboveground insects. First, soils can alter the way plants defend them selves in terms of secondary chemistry and phytohormonal defenses. Second, soils can also directly impact aboveground insects by changing the insect microbiome. This work shows that a large part of the insect microbiome is taken up directly from the soil microbiome, and leads to exciting new research directions on the longterm and evolutionary implications of soils for aboveground insects. Show less
