Plant roots excrete a variety of metabolites into the rhizosphere and create unique habitats for the microbial communities. These microbes exchange their metabolites and significantly impact plant physiology through symbiosis and virulence. Although metagenomic studies have greatly expanded the catalog of the genomic information, much less is studied about the molecular mechanisms underlying the formation of microbial ecosystems. To understand the basis of plant-microbial interactions, my research focuses on developing novel experimental approaches and identifying the quantitative links from genotypes to phenotypes. I will combine a careful characterization of rhizobacterial physiology with a spectrum of advanced capabilities at Berkeley Lab, including functional genomics, genome engineering, and laboratory automation.