Quantitative Proteomics of Chromochloris zofingiensis Reveals the Key Proteins Involved in Cell Growth and Bioactive Compound Biosynthesis

Abstract

Glucose metabolism regulates cell growth and affects astaxanthin accumulation in the green algae Chromochloris zofingiensis. Hub gene functioning in this bioactive compound has been illustrated at the genome, transcriptome and metabolome level, but is rather limited from a proteome aspect. Microalgal cell produce an enhanced biomass (8-fold higher) but decreased lipid and astaxanthin content (~20% less) in the glucose condition compared to the control. Here, we investigate the proteomic response of C. zofingiensis grown with and without glucose using an LC-MS/MS-based Tandem Mass Tag (TMT) approach. The proteomic analysis demonstrated that glucose supplementation triggers the upregulation of 105 proteins and downregulation of 151 proteins. Thus, the carbon and energy flux might flow to cell growth, which increased the associated protein abundance, including DNA polymerase, translation initiation factor, 26S proteasome regulatory subunits, and the marker enzyme of the TCA cycle ribosomal protein. Moreover, the glucose supplement triggered the downregulation of proteins mainly involved in photosynthesis, chloroplasts, valine, leucine and isoleucine biosynthesis, 2-oxocarboxylic acid metabolism, and pantothenate and CoA biosynthesis pathways. This proteomic analysis is likely to provide new insights into algal growth and lipid or astaxanthin accumulation upon glucose supplementation, providing a foundation for further development of C. zofingiensis as oleaginous microalga for bioengineering applications.

Harnessing systems biology approach for characterization of carotenoid biosynthesis pathways in microalgae

“…Regarding the underlying mechanisms of carotenoid accumulation upon glucose supplementation, it was demonstrated that the glucose modulates the transcription of the BKT and CHYb through de novo protein synthesis [ 42 ]. In accordance to these findings, it has been reported that fatty acid accumulation diminishes glucose supplementation [ 40 ].…”

“…More recently, LC-MS/MS-based tandem mass tag (TMT) approach was applied to reveal the key proteins involved in carotenoid biosynthesis in Ch. zofingiensis microalgae [ 40 ]. It has been shown that glucose supplementation induces biomass and astaxanthin accumulation in Ch.…”

The role of amino acid metabolism in salt tolerance mechanism of Medicago sativa and Medicago truncatula

“…It has been reported that the addition of glucose to green algae is mainly involved in photosynthesis, biosynthesis of Leu and Ile, etc [50] . Meanwhile Scarponi [51] found that exogenous addition of Leu and Ile to soybean can effectively reduce the synthesis of glucose and starch. Tyrosine is an aromatic α-amino acid, which has a positive effect on plant leaves and photosynthesis.…”