Molecular characterisation of the genes and enzymes that plants use to produce DMSP

TODD_U21DTP1

Dimethylsulfoniopropionate (DMSP) is an anti-stress compound with key roles in global nutrient and sulfur cycling, signalling and potentially climate regulation. DMSP functions as an osmoprotectant, cryoprotectant, antioxidant and a grazing deterrent in marine microorganisms. Very few plants, including the saltmarsh grass Spartina and tomato, have been shown to produce DMSP. The role of DMSP in these plants is unclear and, despite the biochemical pathway for DMSP synthesis being known, the key enzymes of plant DMSP production remain undiscovered.

This multidisciplinary project aims to unpick the genetics of plant DMSP synthesis and to understand why plants produce this compound. We have identified candidate enzymes for plant DMSP production. Using tomato as a model plant, the student will clone and characterise the enzyme activity of these candidates. They will study the expression of these genes/enzymes in plants grown under different conditions using qRT-PCR and proteomics, and will generate mutant lines using CRISPR gene editing. The student will design experiments to examine the ability of mutant plant lines to withstand varied environmental stresses and determine a role for DMSP in plants. Furthermore, they will be encouraged to develop the project in line with their interests, e.g. to investigate the magnitude of plant DMSP synthesis via bioinformatics. Knowledge of compounds, e.g. DMSP, that might enable crops to grow in sub-optimal saline/drought ridden environments is important.

The student will be based in Todd, Brearley and Miller’s laboratories at UEA that are pioneering in DMSP biology, and provide vibrant, productive and well-resourced environments to study. Indeed, our previous PhD students have published work on DMSP in Nature journals in 2016, 17, 18, 19 and 20. The student will present their data at national and international conferences and receive expert training in analytical chemistry, molecular biology, biochemistry, plant genetics and physiology to define plant DMSP synthesis enzymes.

References:

Curson ARJ, Todd JD, Sullivan MJ, Johnston AWB. (2011). Catabolism of dimethylsulphoniopropionate: Microorganisms, enzymes and genes. Nat. Rev. Microbiol. 9:849–859.

Otte, M. L., Wilson, G., Morris, J. T. & Moran, B. M. Dimethylsulphoniopropionate (DMSP) and related compounds in higher plants. J Exp Bot 55, 1919-1925, doi:10.1093/jxb/erh178 (2004).

Williams BT, Cowles K, Bermejo Martínez A, Curson ARJ, Zheng Y, Liu J et al. (2019). Bacteria are important dimethylsulfoniopropionate producers in coastal sediments. Nat. Microbiol. 4:1815–1825.