Professor Jonathan Todd, School of Biological Sciences, University of East Anglia
Dr Matthew Wallace, School of Pharmacy, University of East Anglia
Ammonia oxidising archaea (AOA) perform a critical step in the global nitrogen cycle and thrive in oceans with massive populations that account for ~ 40% of marine prokaryotes. Most microorganisms produce compounds called osmolytes to cope with environmental stresses including high salinity and drought, but the metabolic pathways and environmental importance of osmolyte production by AOA remains vastly underexplored. In new pilot data we show that abundant AOA produce glycine betaine (GB) and dimethylsulfoniopropionate (DMSP), two ubiquitous marine osmolytes that are critical in global nitrogen and sulfur cycling, respectively, and are major sources of climate-active gases that can impact Earth’s climate. This project will elucidate the metabolic pathways and the significance of GB and DMSP production by AOA in Earth’s oceans. This project is exciting and novel because it explores the much-overlooked role of a hugely abundant group of marine microorganisms in linking nitrogen and sulfur cycling. Furthermore, the project will reveal insights into adaptation strategies of these ubiquitous microbes in the ocean. This project is timely due to the key roles of biogeochemical nitrogen and sulfur cycling in climate change and environmental change.
The student will use multi-omics (transcriptomics, proteomics and metabolomics) approaches with ammonia oxidising archaeal cultures to examine the effect of e.g., salinity and temperature, on osmolyte production and establish up- and downregulated metabolism. Genes responsible for osmolyte production will be cloned, expressed and functionally characterised in host bacteria mutated in varied osmolyte production. Environmental distribution and expression of novel osmolyte pathways will be examined using metagenomics and metatranscriptomics datasets from diverse environments including coastal ecosystems, sediments, deep ocean trenches and open oceans.
The student will be trained in diverse molecular microbial ecology, including microbial cultivation and physiology, analytical chemistry, nucleotide extraction, cloning, protein expression and characterisation, and omics-based approaches including bioinformatics. The student will join a thriving cohort of PhD students at UEA, collaborate with colleagues in Germany and the Netherlands, and present their research in lab meetings, research seminars and national and international conferences.
This project is suitable for candidates with a BSc in microbiology-related disciplines.