Rhizobacteria colonization
Bacterial root colonization was determined at 11 dpi for Arabidopsis and Broccoli and at 14 dpi for Artemisia. Roots were collected in sterile glassware and their fresh weight was determined. Root samples were vortexed for 60 s in 10 mM MgSO4, sonicated for 60 s, and vortexed once more for 15 s. After serial dilution, 50 µL of the suspensions were plated onto PSA (Pf SS101 and Pbg ) and TSA (MB) containing 100 µg mL-1 delvocid (DSM). After 3 days of incubation at 25 °C, the number of colonies were counted for each of the replicates. Bacterial colonization was expressed as colony-forming units (cfu) per gram of root fresh weight.