Microbial diversity
Seeds of uniform size from the maize inbred line B73 were sterilized in sodium hypochlorite for 3 min, rinsed with sterile distilled water, and germinated on wet filter paper for 3 d. Seedlings were then placed in test tubes with 20 mL half-strength MS medium with or without ET or FB1. The experiment was repeated three times, each with three replicates per treatment. After one week of growth, maize root tissue was harvested for transcriptome and microbial diversity analyses.