Distribution of the new functional marker gene (pahE) of aerobic polycyclic aromatic hydrocarbon (PAHs) degrading bacteria in different ecosystems

Understanding the degradation potentials in PAHs-contaminated sites is significant for formulating effective bioremediation strategies. pahE encoding PAHs hydratase-aldolase has been proven as a better new functional marker gene of aerobic PAHs-degrading bacteria to assess the biodegradation potential of indigenous PAHs-degrading bacterial population. However, the distribution of pahE and its relationship with environmental factors remain unknown. The present study observed spatial variations in the diversity and abundance of pahE across oilfield soils, mangrove sediments, and urban roadside soils. nahE from Pseudomonas, bphE from Hyphomonas oceanitis, nagE from Comamonas testosterone, and novel pahE genes were widely present in these PAHs-polluted ecosystems. The abundance of pahE in PAHs-contaminated sites was in the range of 10⁵-10⁶ copies·g^-1 (dry weight). Redundancy analysis and Pearson's correlation analysis implied that the distribution of pahE in the PAHs-contaminated environment was mainly shaped by environmental factors such as PAHs pollution level, nutrient level, salinity, and water content. This work was the first to explore the distribution of the new functional marker gene (pahE) and its links with environmental parameters, which provided new insights into the ecophysiology and distribution of indigenous aerobic PAHs-degrading bacteria in contaminated sites.