Arsenic in an As-contaminated abandoned mine was mobilized from fern-rhizobium to frond-bacteria via the ars gene

The mobilization of arsenic from fern-rhizobium to frond-bacteria in As-contaminated abandoned mine environments was found to be induced by the ars gene. Uncultured Acinetobacter sp. strain MRI67 (DQ539027) and uncultured Buttiaxella sp. strain MRI-65 (DQ539024) were identified in the root/rhizosphere based on the presence of the ars gene. The arsenite-oxidizing bacterial strains isolated in this study were found to grow in the presence of 14 mM sodium arsenite (NaAsO₂). In addition, the concentration of arsenic in five grams of Deparia lobatocrenata As-8 (EU476190) obtained from the Myoungbong abandoned mine area was 8,900 mg/kg ± 56.9, whereas the arsenic concentrations in the frond-rhizoplane of Pseudomonas putida GIST-MRP44-1 (EF623836), the root-rhizoplane of Acinetobacter sp. GIST-MRO62 (EF623849), and the stipe-rhizoplane of P. putida GIST-MRO63 (EF623850) were 41.9 mg/kg ± 1.0 (1 g of tissue), 32.9 mg/kg ± 0.9 (1 g of tissue), and 17.9 mg/kg ± 1.4 (1 g of tissue), respectively. Taken together, these findings suggest that the newly isolated indigenous fern-rhizobium, stipe-bacteria, and frond-bacteria may provide a better understanding of arsenic mobility in the field of molecular geomicrobiology and that it can be applied to the phytoremediation of arsenic-contaminated mines.