P9 - LCM-Rhizomics

Root-structure and soil-texture dependent microbial self-organization in the rhizosphere and in specific cell-types of the endorhizosphere of maize


Root hairs, tubular outgrowths of the root epidermis, play a critical role in carbon and nutrient exchange between host plants and the rhizosphere and act as a determinant of the microbiome thriving at the root-soil interface. The microbial communities inhabiting the rhizosphere engage in complex interactions with their host plants which span from parasitism to mutualism. Consistency and size of the rhizosphere determines the capacity of plants to cope with soil abiotic stresses in crops. Therefore, the rhizosphere microbiome emerges as one of the determinants of plant health, yield potential and resource use efficiency contributing to sustainable agriculture.
The diversiļ¬cation of genes involved in root hair development suggests a substantial divergence in the structure and expression of genes involved in root hair patterning. Thus far, in maize several root hair mutants with contrasting length and density of root hairs and root hair defective (rth) genes controlling root hair elongation have been characterized. The proteins encoded by rth3, rth5, and rth6 are functionally linked during maize root hair formation. Genetic analyses demonstrate that root hair growth and development is genetically controlled by different genes involved in exocytotic vesicle fusion, cellulose synthesis and translational processes.
In the second phase of the SPP2089, we will investigate root-microbe interactions among root hair mutants affected in different genes influencing the length of root hairs. This also supports the potential importance of the rhizosphere size and the capacity for attaching the living area around the roots for the soil microbiome. Overall goal of the project is to obtain a systemic understanding of root hair driven self-organization of the rhizosphere microbiome and its potential feedback on host root morphology, anatomy and gene expression. This goal will be achieved by analyzing the interaction of several root hair mutants of maize which display contrasting root hair phenotypes with respect to length and density and are affected in different genes under two soil conditions (loam and sand). In these experiments we will explore the morphological, anatomical and transcriptomic divergence of different root types and their effects on the composition and diversity of the rhizosphere microbiome under these soil conditions. To this end, candidate genes associated with microbes associated with the root phenotype will be identified and validated by reverse genetics and microbial synthetic communities.

Link to English scientific abstract

Link to German scientific abtract