Application of enterobacterial repetitive intergenic consensus (ERIC)-PCR to resolve taxonomic diversity on the roots of pontederia cordata

Enterobacterial repetitive intergenic consensus (ERIC)PCR fingerprinting and sequencing were utilized to analyze the microbial community on Pontederia cordata roots in different conditions in water purifying tanks. Results indicated that plant physiology was directly associated with the diversity of microbial community on the plant roots. The main species were Alcanivorax, Xanthomonas, Syntrophobacter fumaroxidans, Syntrophus, Chlorobium, Psychrobacter, Desulfotalea psychrophila and Bacteroides. With higher planting density, water dissolved O₂ (DO) and microbial diversity on roots increased, and removal rates of NH₄⁺-N and total phosphorus increased, reaching 33.0% and 59.7%, respectively. The root microbial diversity in aerated tanks exceeded that in non-aerated tanks. In summer, the root microbial diversity obviously exceeded that during the slower growth stage in autumn. Similarly, the removal of nitrogen and phosphorus was more efficient in summer. The plant physiology affected the root microbial community, although Bacteroides and D. psychrophila were the relatively stable dominant bacteria species. The plant physiology affected the water DO and microbe growth on the plant roots, as well as the transformation and degradation of water pollutants by the microbes. This study helped to clarify the relationship between plants and microbes in polluted water treatment and provided useful information for ecological restoration engineering.