Tree phyllospheres are a habitat for diverse populations of CO oxidising bacteria

The phyllosphere, termed as the above-ground parts of plants, is a largely unexplored microbial habitat. Some phyllosphere microorganisms are capable of degrading atmospheric compounds such as phenol, benzene, methanol and polycyclic aromatic hydrocarbons. Many of these compounds are considered pollutants, reducing the quality of air. Air pollution is responsible for an estimated 5.5 million premature deaths globally. It is therefore important to investigate processes which may mitigate and reduce atmospheric pollutants such as removal or detoxification by phyllosphere microbiota. Carbon monoxide (CO) is a toxic and ubiquitous atmospheric gas which contributes to air pollution. While it is known that some bacteria in soils and aquatic ecosystems are capable of CO oxidation, the extent to which phyllosphere microbiota may play a role in the oxidation of CO was previously unknown. This project utilised a range of culture dependent and culture independent techniques to investigate whether bacterial communities are capable of CO oxidation and which species may be involved.