DMSP cycling in unexpected places

Scientific background: Dimethylsulfoniopropionate (DMSP) is known as a marine anti-stress compound made by marine algae and bacteria. It has key roles in global nutrient and sulfur cycling, signalling, and microbial DMSP catabolism releases climate-active gases (CAG), notably dimethylsulfide (DMS). However, DMSP is also produced by many terrestrial plants, including wheat that is farmed on >2x108 hectares globally, and is found at appreciable levels in wheat rhizosphere samples. Little is known about microbial DMSP catabolism in terrestrial plant settings and key questions remain unanswered, e.g. what microbes degrade plant-made DMSP, which pathways do they use and what is their impact on CAG production?

Methodology: This multidisciplinary PhD will address these unknowns by working on wheat cropped in East Anglia. The individual will conduct a seasonal field-study of DMSP production and cycling on wheat plantations. DMSP production, accumulation, microbial catabolism and CAG flux will be investigated at the process (using e.g. gas chromatography, mass spectroscopy and autonomous DMS sensors) and molecular (using e.g. RT-qPCR and assays of key genes/enzymes) levels in/from plant tissue and soils - to explore their environmental significance. To complement this process-led work, the PhD will conduct culture-dependent (microbial enrichment, isolation and characterisation of model organisms) and -independent microbiology (e.g. DNA-stable isotope probing and multi-omics analysis) to identify microbes importing and catabolising DMSP as a nutrient in wheat samples, their biodiversity, the pathways used, the CAG liberated and how environmental changes impact these. Finally, the student will be encouraged to develop the project to their interests, e.g. to investigate any plant growth promoting effects of microbial isolates or novel DMSP cycling genes.

Training: The student will receive exceptional interdisciplinary training at UEA and PML spanning DMSP biology, molecular ecology and microbiology, plant physiology, bioinformatics, analytical chemistry, fieldwork and in scientific writing and presentation.