Interactions between soil microorganisms and plants

Orchis purpurea (Stor Gøgeurt) from Møns Klint. Photo: Mirnesa Rizvanovic

Here, we examine the relationship between specific soil microbial communities and plant growth; we are interested in both natural plant communities and crop plants. Wild orchids are often considered important indicators of valuable nature; thus all orchid-species are protected in Denmark.

Orchids are often found in valuable natural habitats, for example, on “Høje Møn” and in “Allindelille Fredsskov”. At locations where orchids occur, their distribution is frequently patchy; moreover orchids often pop up in "weird" places such as e.g. garden lawns.

This suggests that very specific conditions govern their occurrence. Important factors that determine their distribution are likely both abiotic (pH, lime content, humidity, etc.) and biotic i.e. specific soil-organisms. Most important are probably the fungi that the orchids parasitize “orchid mycorrhiza”.

In OP-RICE-ING, we focus on development of consortia of soil-microorganisms in the soil surrounding the plant-roots to optimally support plant-growth. Plants supplied with sufficient amounts of chemical fertilizers and pesticides can principally do without microorganisms. However, for economic and environmental reasons it is desirable to grow plants with a minimum of chemicals. Here, the plants are strongly dependant on their root microorganisms.

The plant-microorganism relationship is however always a trade-off. Whereas plants on one hand need the soil organisms; most organisms are also to some extent harmful to the plants. Hence, to construct exactly the right consortium is a difficult task. The final goal here will be to design microbial communities that optimally and specifically support plant growth. We will also use Next Generation Sequencing to describe these consortia.