To analyze the growth inhibitory mechanism of a 2-aminobenzoic acid (2-AA) derived from Bacillus cereus EJ-121, we treated Arabidopsis thaliana plants with 2-AA, 2-AA analogs, auxin (NAA), a known auxin transport inhibitor [2,3,5-triiodobenzoic acid (TIBA)], and an ethylene action inhibitor [silver thiosulfate (Ag)]. Root development was significantly inhibited by $50{mu}M$ 2-AA, whereas the growth of bacteria and yeast was undeterred. The application of two 2-AA analogs -- 3-aminobenzoic acid (3-AA) and 4-aminobenzoic acid (4-AA)-- did not impair Arabidopsis root growth at concentrations below $100{mu}M$. These results suggest that the effect of 2-AA is not due to its chemical structure, but because of its conversion to another metabolite, IAA. To confirm this, we supplemented TIBA in the growth medium, and found that the degree of inhibition was significantly reduced. Similarly, when plants were co-treated with $100{mu}M$ Ag, the negative effect of $50{mu}M$ 2-AA was greatly diminished. All of these observations support the proposal that this inhibition results from the conversion of 2-AA to IAA. Furthermore, the increased auxin level leads to a rise in ethylene synthesis, which then blocks root growth and, ultimately, retards overall plant development.