A 40 mL broth cultures (OD600, 1.0) of the PGPR was applied to each respective pot prior to transplanting. The same volume of sterile media (without inocula) was applied to the control pots. The pots were wrapped with aluminum foil to prevent light effect from inhibiting root growth and aerated with an air pump for six hours at sixhourly
intervals to ensure an uninhibited root respiration and bacterial growth.