Characterization of genes and genotypes which contribute to lipid accumulation in Saccharomyces cerevisiae and on Zea mays silks

Lipids are hydrophobic molecules that are essential for life and allow organisms to adapt to changing environments. The chemical properties that make these molecules indispensable for biological activity also make them useful as products that are ubiquitous to human industry and everyday life. Investigating the biological role and biosynthesis of these compounds can reveal new routes for producing efficient and sustainable products and crops. Herein, the study and characterization of lipid biology, genetics, and biochemistry is described in three model systems. Using a forward genetic screen, several genes that impact lipid accumulation in Saccharomyces cerevisiae were elucidated. Lipid constituents also coat plant cuticles, creating a barrier between hydrated tissues and the environment. To investigate the protective role of these surface lipids against tissue desiccation, stigmatic maize silks were subjected to temperature-relative humidity combinations and assessed for their rates of water loss across these conditions, while their surface lipid profiles were assessed in tandem to consider association between surface lipids and rates of water loss. Alkane accumulation was found to predict lower rates of water loss, suggesting that alkanes play a protective role against silk desiccation. Because the genes directly involved in alkane biosynthesis within maize have not been fully described, the maize gene, ZmGl1-like2, was explored for its potential role in the terminal steps of alkane biosynthesis due to sequence homology to the putative fatty acyl reductase, CER3. Metabolomic characterization in Arabidopsis cer3 mutants overexpressing ZmGl1-like2 revealed that zmGL1-like2 is a functional homolog to CER3 thereby furthering our understanding of alkane biosynthesis in maize, a major cereal crop. Together, this work identifies novel mutations and genes involved in lipid biosynthesis and regulation and considers the relationship between lipid accumulation the underlying biological significance imparted by the lipid metabolome