This study reveals the complex structure of bacterial and archaeal communities associated with a Canna
indica plant microbial fuel cell (PMFC) and its electricity production. The PMFC produced a maximum current
of 105 mA/m2 by utilizing rhizodeposits as the sole electron donor without any external nutrient or
buffer supplements, which demonstrates the feasibility of PMFCs in practical oligotrophic conditions
with low solution conductivity. The microbial diversity was significantly higher in the PMFC than
non-plant controls or sediment-only controls, and pyrosequencing and clone library reveal that rhizodeposits
conversion to current were carried out by syntrophic interactions between fermentative bacteria
(e.g., Anaerolineaceae) and electrochemically active bacteria (e.g., Geobacter). Denitrifying bacteria and
acetotrophic methanogens play a minor role in organics degradation, but abundant hydrogenotrophic
methanogens and thermophilic archaea are likely main electron donor competitors.