All land plants grow in association with complex microbial communities both on above ground plant organs (called the phyllosphere) and below the ground on roots (called the rhizosphere). The relationships between a microbiota (the community of microbes intimately associated with a plant) and its host can vary from pathogenic to symbiotic. The microbiome (the set of genes encoded by any particular microbiota) can perform ecosystem services by providing the host plant with critical nutrients, protection from pathogens, production of functional plant hormones, and provision of tolerance to stressors like heat. The plant, in turn, provides the microbiome with an improved environment, including a complex array of energy sources released by deposition of plant-based sugars into the soil. Decaying plant tissue and carbon-rich root exudates redirect large amounts of fixed atmospheric carbon to the soil, making the rhizosphere a large carbon sequestration zone, important in the balance of carbon in a changing environment. Site specific characteristics of climate and soil that influence the yield of maize and other crops and the productivity of any plant community rely in part on the respective rhizosphere microbiome. This research will ultimately lead to agricultural practices designed to increase plant health and productivity, carbon sequestration, and disease resistance through the rational utilization of the probiotic capacity of soils and the local environment. The project team is a collaborative interdisciplinary group from UNC-Chapel Hill, Cornell and the DOE Joint Genome Institute. The experiments to be carried out will define the rhizosphere microbiota and associated microbiome using two important model plant species: Arabidopsis thaliana, the premier model for rapid discovery in plant biology, and Zea mays, the premier model for genetic dissection of complex traits in crops. Data generated by the project will be made freely available, and will provide starting points for a variety of deeper studies into the complexities of host-microbe interactions. The project will provide training opportunities for undergraduates, doctoral students and post-doctoral fellows.
