root-associated microbial in constructed wetlands

To understand the response of plant and root-associated microorganism to phosphorus chemical industry tailwater, we collected the plant and root-associated microorganism samples after one year of constructed wetlands operation. The samples were marked as HCW. For the control analysis, we also collected the same plant species and their root-associated microorganism samples marked as LCW in nearby constructed wetlands which received the tailwater of an integrated sewage treatment plant.For root-associated microorganism samples collection, surface substrates of the plant were removed, and the sterile tweezers and scissors were used to collect the plant roots into a 50 ml sterile centrifugal tube, and then the tube was put into dry ice for quick freezing. 25 mL of 1 × PBS buffer were used to wash the root when brought back to the laboratory, and sonicated for 5 min, vortexed 1min, repeating three times. After removing the roots with sterile tweezers, PBS solution was filtered through 0.22 μm sterile membranes to extract root-associated microorganism, which was then kept at 80 °C.