Roots from 4-day-old A. thaliana seedlings were treated with either Caulobacter RHG1 or Bacillus sp. and harvested at 12 or 48 hours after treatment. Arabidopsis thaliana ecotype Col0 seeds were surface sterilized with chlorine gas followed by stratification at 4 ⁰C in the dark for 2 days. Seeds were sown on agar-solidified plant growth medium (2.3 g/l MS, 0.5 g/l MES, 8 g/l plant tissue culture agar; pH 5.7) with a nylon mesh (mesh size 20 µM, Prosep) and incubated vertically in a tissue culture room at 21 ⁰C under long-day conditions (16 h light/8 h dark) for 4 days. Four-day-old A. thaliana seedlings were treated with either Caulobacter RHG1 or Bacillus inoculum (OD600=0.01) and roots were harvested at 12 and 48 hours after treatment. RNA was extracted with the RNeasy Plant Mini Kit (Qiagen) and RNA concentrations were measured with a ND-1000 Spectrophotometer (Thermo Fisher Scientific Nanodrop). Library preparation was done using the TruSeq stranded RNA Sample Preparation Kit v3 (Illumina).