Gene expression profiling of astaxanthin and fatty acid pathways in Haematococcus pluvialis in response to different LED lighting conditions

Abstract

Haematococcus pluvialis is a green microalga of major interest to industry based on its ability to produce large amounts of astaxanthin. Biosynthesis of astaxanthin and its mono- and di-esters was significantly stimulated under 150 μmol m s of white LED (W-150) compared with lower light intensities, but the highest astaxanthin amounts were produced under 70 μmol m s of blue LED (B-70). Transcripts of astaxanthin biosynthesis genes psy, crtO, and bkt2 were upregulated under W-150, while psy, lcy, crtO, and crtR-B were upregulated by B-70. Total fatty acid content and biosynthesis genes fata and all dgat genes were induced under W-150, while C18:3n6 biosynthesis and dgat2a expression were specifically stimulated by B-70 which was correlated to astaxanthin ester biosynthesis. Nitrogen starvation, various LEDs and the identified upregulated genes may provide useful tools for future metabolic engineering to significantly increase free astaxanthin, its esters and fatty acid precursors in H. pluvialis.

Transcriptome-wide analysis of auxin-induced carotenoid accumulation in Chlorella microalgae

“…No difference was found across days in control samples, suggesting that the modification of carotenoid profile was due to the action of IAA and not culture conditions. These results are in agreement with a previous study of (Ma et al 2017). Our data also showed that LCYb and LCYe both increased in expression, although the induction was more pronounced in LCYb.…”

Characterization of type-2 diacylglycerol acyltransferases in Haematococcus lacustris reveals their functions and engineering potential in triacylglycerol biosynthesis and possible roles in astaxanthin esterification

“…Haemaococcus lacustris is not only able to produce a substantial amount of TAG but also the highest content of AST under stress conditions, which represents a leading algal candidate of industrial potential [29][30][31][32][33][34][35]. For example, HL and ND stresses can effectively promote the accumulation of AST and TAG in H. lacustris [32][33][34][50][51][52][53].…”

“…AST/TAG accumulation and HpDGAT2 genes transcription expression upon HL and ND stresses High light (HL) and nitrogen de cient (ND) stresses can effectively promote the accumulation of AST and TAG in H. lacustris [32][33][34][50][51][52][53]. To understand the relationship between HpDGAT2s expression and TAG/AST biosynthesis, time-course patterns of algal biomass, transcription expression, total AST (T-AST), and total TAG (T-TAG) contents in photoautotrophic cultures of H. lacustris under HL, ND, and double HL+ND stresses were studied ( Fig.…”

“…Previous studies have indicated that DGATs enzymes are probably responsible for both AST esteri cation and TAG biosynthesis in H. lacutris [33,34]. Therefore, the time-course pattern of HpDGAT2s transcription expression was determined to reveal whether these genes were involved in the HL, ND, and HL-1/4N induction processes.…”

“…Natural AST is a red-colored carotenoid with strong antioxidant ability and important commercial value [31]. H. lacustris is also represented a potential source of TAG, since a considerable increase in TAG content accompanies the accumulation of AST [32][33][34][35]. Moreover, the previous studies have indicated that the main form of AST is esteri ed AST (EAST, 95%) including monoester AST (MAST, 70%) and diester AST (DAST, 25%), which is stored in TAG rich cytosolic oil bodies (OBs) [36][37][38][39][40].…”