LEVERAGING THE ROOT MICROBIOME FOR SUSTAINABLE CEREAL CROP PRODUCTION

In the face of the twin challenges of climate change and an increasing world population, there is a need for improved sustainability in the agricultural industry. In particular, cultivation of the major cereal crop maize, relies heavily on natural gas intensive and environmentally damaging synthetic nitrogenous fertilizers. Using nitrogen fixing microbes as biofertilizers has the potential to improve the sustainability of maize cultivation, however knowledge of the bacterial interspecies interactions governing nitrogen fixation in the rhizosphere microbiome remains limited. I propose to investigate the ecological and molecular mechanisms affecting nitrogen fixation in a synthetic microbiome system and use this knowledge to develop microbial consortia for use as robust crop inoculants. I will use high-throughput in vitro experimentation paired with computational modeling to elucidate the dynamics of community assembly and nitrogen fixing ability. I further propose to determine how the interspecies interactions present within the maize rhizosphere microbiome are affected by changes in the root exudate nutrient environment. Additionally, I will explore the effect of oxygen levels on community nitrogen fixation, metabolically engineering key, non-diazotrophic species for enhanced oxygen consumption. Through this interdisciplinary postdoctoral research project, I will provide the agricultural field with insight into the workings of the rhizosphere microbiome as well as designed microbial communities for use in sustainable fertilizers strategies.1. Design microbial community inoculants for enhanced nitrogen fixation.2. Design communities robust to changes in root exudation.3. Engineer key, non-diazotrophic strains to support community nitrogen fixation through oxygen consumption.