One hundred Cu-resistant-endophytic bacteria were isolated from Cu-tolerant plants grown on Cu mine
wasteland, of which, eight Cu-resistant and 1-aminocyclopropane-1-carboxylate (ACC) deaminase-producing
endophytic bacteria were obtained based on the ACC deaminase activity of the bacteria and characterized
with respect to metal resistance, production of ACC deaminase, indole-3-acetic acid (IAA) as
well as siderophores and mineral phosphate solubilization. Ralstonia sp. J1-22-2, Pantoea agglomerans
Jp3-3, and Pseudomonas thivervalensis Y1-3-9 with higher ACC deaminase activity (ranging from 213 to
370 lM a-ketobutyrate mg1 h1
) were evaluated for promoting plant growth and Cu uptake of rape
grown in quartz sand containing 0, 2.5, and 5 mg kg1 of Cu in pot experiments. The eight bacteria were
found to exhibit different multiple heavy metal resistance characteristics, to show different levels of ACC
deaminase activity and to produce indole acetic acid. Seven bacteria produced siderophores and solubilized
inorganic phosphate. Pot experiments showed that inoculation with the strains (J1-22-2, Jp3-3, and
Y1-3-9) was found to increase the biomass of rape. Increases in above-ground tissue Cu contents of rape
cultivated in 2.5 and 5 mg kg1 of Cu-contaminated substrates varied from 9% to 31% and from 3 to 4-fold
respectively in inoculated-rape plants compared to the uninoculated control. The maximum Cu uptake of
rape was observed after inoculation with P. agglomerans Jp3-3. The results show that metal-resistant and
plant growth promoting endophytic bacteria play an important role in plant growth and Cu uptake which
may provide a new endophytic bacterial-assisted phytoremediation of Cu-contaminated environment.