Pantoea sp. YR343, isolated from the Populus deltoides rhizosphere, is a robust plant root colonizer that produces indole-3-acetic acid (IAA). Genomic and metabolomic analyses predicted that Pantoea sp. YR343 synthesizes IAA primarily using the indole-3-pyruvate pathway. Pantoea sp. YR343 proteomes showed upregulation of IpdC for growth in the presence of tryptophan or IAA versus controls.