Carotenoids Overproduction in Dunaliella Sp.: Transcriptional Changes and New Insights through Lycopene β Cyclase Regulation

Abstract

Dunaliella is a green microalga known for its ability to produce high levels of carotenoids under well-defined growing conditions. Molecular responses to the simultaneous effect of increasing salinity, light intensity and decrease of nitrogen availability were investigated in terms of their effect on different metabolic pathways (isoprenoids synthesis, glycolysis, carbohydrate use, etc.) by following the transcriptional regulation of enolase (ENO), 1-deoxy-D-xylulose 5-phosphate synthase (DXS), lycopene β-cyclase (LCYB), carotene globule protein (CGP), chloroplast-localized heat shock protein (HSP70), and chloroplast ribulose phosphate-3-epimerase (RPE) genes. The intracellular production of carotenoid was increased five times in stressed Dunaliella cells compared to those grown in an unstressed condition. At transcriptional levels, ENO implicated in glycolysis, and revealing about polysaccharides degradation, showed a two-stage response during the first 72 h. Genes directly involved in β-carotene accumulation, namely, CGP and LCYB, revealed the most important increase by about 54 and 10 folds, respectively. In silico sequence analysis, along with 3D modeling studies, were performed to identify possible posttranslational modifications of CGP and LCYB proteins. Our results described, for the first time, their probable regulation by sumoylation covalent attachment as well as the presence of expressed SUMO (small ubiquitin-related modifier) protein in Dunaliella sp.

Identification, Characterization, and Expression Analysis of Carotenoid Biosynthesis Genes and Carotenoid Accumulation in Watercress (Nasturtium officinale R. Br.)

“…Previous studies reported that lycopene cyclase uses FAD as a cofactor. 48 Moise et al 49 reported that most of the enzymes involved in the transformation of lycopene and carotene are membrane-bound. Similarly, in NoLCYB the binding site is close to the membrane helix and the FAD-binding domain is present near the enzyme (data not shown).…”

Biomolecules from Microalgae and Cyanobacteria: Applications and Market Survey

“…Nevertheless, bioactive compounds also can be synthesized from secondary metabolism with cosmetics and phar-maceutical aims [24,52]. Similarly, Cyanobacteria from marine and freshwater sources are known to produce a variety of bioactive compounds (secondary metabolites) that are derived from mixed biosynthetic pathways endowed with diverse biological activities, including antiviral, antibacterial, antifungal, antimalarial, antitumoral, and antiinflammatory properties [53][54][55].…”

Ecological and Biotechnological Aspects of Pigmented Microbes: A Way Forward in Development of Food and Pharmaceutical Grade Pigments

“…Dunaliella sp. carotenoids are mainly triggered by two essential genes CGP and LCYB [ 171 ]. In Rhodotorula mucilaginosa , CAR gene cluster synthesizes carotenoids [ 172 ].…”