434103 Transforming Our Understanding of Algal and Plant Lipid Metabolism with a High-Throughput Whole Genome Functional Genomics Strategy

Thursday, November 12, 2015: 2:30 PM
150D/E (Salt Palace Convention Center)
Robert Jinkerson and Martin Jonikas, Carnegie Institution, Stanford University, Stanford, CA

Microalgae have been of recent interest for use as a biofuel feedstock because they can produce large quantities of lipids, contain little recalcitrant biomass, and do not impact the food supply. Lipid metabolism is central to algal/plant biology, human nutrition, and biofuel production; however, details on how it is regulated, what genes are involved but currently unknown, and how these metabolic pathways can be optimized for bioenergy production remain unknown.

To address these questions we are using a newly developed functional genomics strategy to identify all single gene mutations that alter cellular lipid metabolism in Chlamydomonas at a genome scale, a first for a unicellular eukaryotic phototroph. A genome-wide, barcoded insertional mutant library has been created and genomic insertion sites mapped. A Fluorescence-Activated Cell Sorting (FACS) pipeline has been used to isolate mutants with increased and decreased triacylglyceride (TAG) content. Mutants identified in the screen have been characterized for total TAG content, fatty acid distribution, and lipid class abundance. These mutants are revealing insights into the functional relationship between specific genes and lipid metabolism in algae. We are pursuing genes involved in the regulation of lipid metabolism, in particular, genes involved in the switch from basal TAG production to hyper-accumulation during nitrogen deprivation, or so called 'lipid triggers'. This whole genome functional genomics approach to studying algal lipid metabolism is yielding insights that can inform metabolic engineering strategies to maximize biofuel production in these organisms.

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