Abstract：The impact of nanometer titanium dioxide(nano-TiO2) to the phyllosphere bacterial community were assessed using culturable-depend and PCR-DGGE methods. Results showed that quantities of the culturable phyllosphere bacteria were reduced with the increasing concentrations of the nano-TiO2. The quantity of the culturable phyllosphere bacteria decreased from 1.8×107 to 3.1×106 cfu/g along with the concentrations of the nano-TiO2 from 0.002 to 20 mg/mL. The diversity of the phyllosphere bacteria was also analyzed by PCR-DGGE. When the concentrations of the nano-TiO2 were higher than 0.02 mg/mL the DGGE bands was significantly lower than that of the control. Sequencing results of the bands from the DGGE gel showed that there were at least 7 bacterial genera on the cucumber phyllosphere. And only one phyllosphere uncultured bacterium was not influenced by the concentration of the nano-TiO2.
