P15 - Mycorrhizosphere

Effect of genetic perturbations on the spatial heterogeneity and co-occurrence patterns in the microbiota of the maize mycorrhizosphere in interaction with two different soils


A huge variety of microbes play important roles in thriving of maize (Zea mays) in agricultural soils. Arbuscular mycorrhizal fungi (AMF) belong to the maize root microbiota and deliver a large proportion of mineral nutrients (e.g. phosphate) to the plant through their hyphal network. At the present, nutritional and metabolic interactions between plants, AMF and their microbiota, and how they affect soil properties, the mycorrhizospheric microbiota and plant growth, is far from being fully understood.
To elucidate how plant factors shape the interdependency between root, microbiota and soil, we are going to investigate the microbiome variation in the mycorrhizosphere, comprising the root endosphere, rhizosphere and hyphosphere, of wild type maize and three maize mutants affected in root hair formation, rhizosecretion and mycorrhizal nutrient uptake (rth3, ccd8, pht1;6) when grown in two soil types. We are establishing a rich collection of fully indexed isolates of mycorrhiza-associated microbes to establish synthetic communities (SynComs) of reduced complexity representing the genetic diversity of the natural microbial community of mycorrhizal maize. Germ-free maize (wild type and mutants) will be re-populated with these microbiota to assess their impact on host fitness and performance and cross-kingdom species interactions.
Secondly, we will explore co-occurrence patterns of root microbiota members and identify keystone species, that strongly affect the dynamics of the communities in the mycorrhizosphere, by using a mycorrhizal microbiome network analysis.
Thirdly, SynComs including fungal and bacterial isolates with keystone species from mycorrhizal maize roots will enable studying the biological role(s) of individual mycorrhizospheric microorganisms and underlying molecular mechanisms under controlled and reproducible conditions.

Link to English scientific abstract

Link to German scientific abstract