Triacylglycerol biosynthesis in Chlamydomonas reinhardtii

Rachel Miller1,2, Eric Moellering2,3, Xiaobo Li2,4, Astrid Vieler3, Barbara B. Sears4, and Christoph Benning3

1) Cell and Molecular Biology Program, 2) Dept. of Energy Plant Research Laboratory, 3) Department of Biochemistry, 4) Plant Biology Dept., Michigan State University, East Lansing, MI 48824

Biofuels provide a potential alternative to the use of fossil fuels, and thus are currently an important area of research. Microalgae are prominent candidates for biofuel production, particularly the production of biodiesel from triacylglycerols (TAG), but more knowledge of the biochemical pathways involved in the synthesis of these compounds is needed before they can become viable biofuel sources. Chlamydomonas is being used as a model for the study of TAG synthesis in microalgae. Diacylglycerol acyltransferases (DGATs) catalyze the final step of TAG synthesis. Five putative DGATs were identified in the Chlamydomonas genome. The enzymatic activity of these putative DGATs was tested by complementation of yeast DGAT-knockout mutants, with two of them having confirmed acyltransferase activity. The role of these genes in TAG synthesis in Chlamydomonas is being confirmed by construction of over-expression and knock-down strains. Regulation of the TAG synthesis pathway is being examined through transcript profiling. Five putative transcription factors were found in the first screen, with two confirmed in the second screen. The activity of these putative transcription factors will be tested in over-expression lines.

e-mail address of presenting author: mill1663@msu.edu