Proteome response ofPhaeodactylum tricornutum, during lipid accumulation induced by nitrogen depletion.
Nitrogen stress is a common strategy employed to stimulate lipid accumulation in microalgae, a biofuel feedstock of topical interest. Although widely investigated, the underlying mechanism of this strategy is still poorly understood. We examined the proteome response of lipid accumulation in the model diatom,Phaeodactylum tricornutum(CCAP 1055/1), at an earlier stage of exposure to selective nitrogen exclusion than previously investigated, and at a time point when changes would reflect lipid accumulation more than carbohydrate accumulation. In total 1043 proteins were confidently identified (≥ 2 unique peptides) with 645 significant (p< 0.05) changes observed, in the LC-MS/MS based iTRAQ investigation. Analysis of significant changes in KEGG pathways and individual proteins showed that under nitrogen starvationP. tricornutumreorganizes its proteome in favour of nitrogen scavenging and reduced lipid degradation whilst rearranging the central energy metabolism that deprioritizes photosynthetic pathways. By doing this, this species appears to increase nitrogen availability inside the cell and limit its use to the pathways where it is needed most. Compared to previously published proteomic analysis of nitrogen starvation inChlamydomonas reinhardtii, central energy metabolism and photosynthesis appear to be affected more in the diatom, whilst the green algae appears to invest its energy in reorganizing respiration and the cellular organization pathways.
ChELSI Institute, Advanced Biomanufacturing Centre, Department of Chemical and Biological Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD, United Kingdom.
Joseph
J
Longworth
ChELSI Institute, Advanced Biomanufacturing Centre, Department of Chemical and Biological Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD, United Kingdom.
Danying
D
Wu
ChELSI Institute, Advanced Biomanufacturing Centre, Department of Chemical and Biological Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD, United Kingdom.
María
M
Huete-Ortega
ChELSI Institute, Advanced Biomanufacturing Centre, Department of Chemical and Biological Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD, United Kingdom.
Phillip C
PC
Wright
ChELSI Institute, Advanced Biomanufacturing Centre, Department of Chemical and Biological Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD, United Kingdom.
Seetharaman
S
Vaidyanathan
Biofuels; Chlamydomonas reinhardtii; Lipid production; Microalgae; Quantitative proteomics; iTRAQ