The polar oceans are unique and highly prolific ecosystems with disproportionately large impacts on global climate and biogeochemical cycles. They are also regions highly sensitive to climate change. Sea-ice algae are important components to polar food webs, climate, and biogeochemical cycles. Ice-algae have adapted physiological mechanisms to thrive under extreme environmental conditions and production of the sulfur compound dimethylsulfoniopropionate (DMSP), which plays important roles in climate and biogeochemical cycles, is likely one such mechanism. Understanding catabolism of DMSP is fundamental to predicting inputs on climate and biogeochemical cycles, yet nothing is known about catabolism of this compound within ice-algae. The aim of this studentship will be to identify potential catabolism pathways of DMSP in the model ice diatom Fragilariopsis cylindrus using RNA-Seq techniques. One of DMSP's proposed physiological functions is that of an osmolyte.  Shifts to low salinity, representative of those encountered within sea-ice, have provided evidence for F. cylindrus DMSP catabolism. Other environmental variables also influence DMSP production and catabolism. This project will use laboratory experiments to examine environmental regulation of DMSP metabolism with the goal of identifying for the first time algal DMSP catabolic pathways. Furthermore, it will provide important insights into molecular responses to hyposalinity conditions. This project will complement recent F. cylindrus proteomics experiments which used high salinity conditions to identify candidate enzymes for the synthesis pathway of DMSP (Lyon et al., 2011) that are currently being validated by molecular genetic techniques and will expand on previous genetic work on bacterial DMSP catabolism (Todd et al., 2007). The student will be part of a local research group composed of Drs. A. Curson, B. Lyon, T. Mock, and J. Todd, along with various international collaborators. An ideal candidate will have background in cell physiology, molecular biology and bioinformatics and/or a keen interest in these areas. Overarching goals of this studentship are to develop molecular targets for upcoming Antarctic research expeditions examining ice algae DMSP metabolism and expand knowledge on polar molecular adaptation mechanisms. 

Lyon, B. R., P. A. Lee, J. M. Bennett, G. R. DiTullio and M. G. Janech (2011). "Proteomic analysis of a sea-ice diatom: Salinity acclimation provides new insight into the dimethylsulfoniopropionate production pathway." Plant Physiology 157(4): 1926-1941.

Todd, J. D., R. Rogers, L. You Guo, M. Wexler, P. L. Bond, S. Lei, A. R. J. Curson, G. Malin, M. Steinke, A. W. B. Johnston, et al. (2007). "Structural and regulatory genes required to make the gas dimethyl sulfide in bacteria." Science 315: 666-669.