title: Isolation and characterization of a stress-inducible Dunaliella salina Lcy-beta gene encoding a functional lycopene beta-cyclase.
abstract: The halotolerant green alga Dunaliella salina accumulates large amounts of beta-carotene when exposed to various stress conditions. Although several studies concerning accumulation and biotechnological production of beta-carotene have been published, the molecular basis and regulation of the genes involved in carotenoid biosynthesis in D. salina are still poorly known. In this paper, we report the isolation and regulation of the lycopene beta-cyclase (Lcy-beta) gene by abiotic stress. The function of this gene was determined by heterologous genetic complementation in E. coli. Gene expression and physiological analyses revealed that D. salina Lcy-beta steady-state transcript and carotenoid levels were up-regulated in response to all stress conditions tested (salt, light and nutrient depletion). The results presented here suggest that nutrient availability is a key factor influencing carotenogenesis as well as carotenoid biosynthesis-related gene expression in D. salina.
authors.affiliation: Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, Faro, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Ramos
authors.forename: Sacha
authors.initials: S
authors.lastname: Coesel
authors.forename: Ana
authors.initials: A
authors.lastname: Marques
authors.forename: Marta
authors.initials: M
authors.lastname: Rodrigues
authors.forename: Alexandra
authors.initials: A
authors.lastname: Baumgartner
authors.forename: João
authors.initials: J
authors.lastname: Noronha
authors.forename: Amélia
authors.initials: A
authors.lastname: Rauter
authors.forename: Bertram
authors.initials: B
authors.lastname: Brenig
authors.forename: João
authors.initials: J
authors.lastname: Varela
mesh_terms: D020418:Algal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D001419:Bacteria / Q000145:classification / Q000235:genetics; D002338:Carotenoids / Q000235:genetics / Q000378:metabolism; D000460:Chlorophyta / Q000145:classification / Q000201:enzymology* / Q000235:genetics* / Q000502:physiology; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D015971:Gene Expression Regulation, Enzymologic; D019753:Intramolecular Lyases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D010944:Plants / Q000145:classification / Q000235:genetics; D016415:Sequence Alignment
chemical_list: D020418:Algal Proteins; D002338:Carotenoids; D019753:Intramolecular Lyases; C070925:lycopene cyclase-isomerase