PhD Candidate Virginia Tech Blacksburgq, Virginia, United States
Caitlin Cridland (Virginia Tech)| Eric Land (North Carolina State University)| Phoebe Williams (William & Mary)| Sherry Hildreth (Virginia Tech)| Rich Helm (Virginia Tech)| Imara Perera (North Carolina State University)| Glenda Gillaspy (Virginia Tech)
Under changing environmental conditions, plants are able to modulate their lipids to respond to varying nutrient availability. Phosphate (Pi) is an essential nutrient for plants, required for plant growth and seed viability. Under Pi stress, plants undergo dynamic morphological and metabolism changes to leverage available Pi, including the modulation of lipids. Plants have been shown to “remodel” their lipid membrane profiles under phosphate starvation, degrading phospholipids in the cell membranes and utilizing the generated phosphorus for essential biological processes. By concomitantly inducing a phospholipid hydrolysis pathway and galactolipid biosynthetic pathway, membrane phospholipids are replaced by non-phosphorus containing galactolipids and sulfolipids. The inositol phosphate (InsP) signaling pathway is a crucial element of the plant’s ability to respond to changing energy conditions. Inositol hexakisphosphate (InsP6) is the most abundant InsP signaling molecule and can be phosphorylated further by VIP kinases, resulting in inositol pyrophosphates (PP-InsPs). PP-InsPs have high energy bonds and have been linked to maintaining Pi and energy homeostasis in yeast and plants. Using liquid chromatography-mass spectrometry and tandem mass spectrometry, we have examined the lipid profiles of three Arabidopsis PP-InsP mutants, in response to Pi depletion, to address the role of PP-InsPs in Pi sensing. Our results suggest that PP-InsPs play a crucial role in Pi sensing and are involved in the regulation of lipid biosynthesis. Furthermore, the changes in the abundance of lipids suggest a possible direction for future seed oil engineering strategies.