Analysis of Bacterial Communities associated with the Tidal Zone Grass Puccinellia in Response to Diesel Spills

Abstract

Contamination from petroleum products and hydrocarbons is one of the major sources of pollution worldwide. The use of plants or microbes to reduce pollution is called bioremediation and is a cheap and environmentally friendly alternative to mechanical or chemical clean-up. A good understanding of native plants and microbes is required to implement bioremediation. In this study, the common and widespread tidal grass Puccinellia sp. and its associated root microbiome were subjected to diesel contamination to assess their bioremediation potential. The experiment lasted 13 weeks and included three treatments: control, low diesel concentration and high diesel concentration. Rhizosphere samples were taken at four time points during this period and the bacterial community was analysed using 16 S sequencing. Prior to sequencing, several changes had to be made to the protocol to overcome difficulties. However, the method used did not yield sufficient DNA sequences and the analysis was limited to a descriptive study. The results show that there was a clear difference between rhizosphere and bulk soil bacterial communities. Rhizosphere communities have higher diversity and relatively stable community composition over time and treatment. In contrast, bulk soil communities have lower diversity and change over time and treatment. All results indicate a strong influence of plant on bacterial community composition, more than diesel. All plants survived the diesel contamination, and all treatments contained up to 60 % of bioremediation-relevant bacteria, indicating the bioremediation potential of Puccinellia sp. and its rhizosphere.