Project description:Dunaliella salina Bardawil (also known as Dunaliella bardawil) is an extremophilic, unicellular green alga from the Chlorophyte lineage. D. salina is found in hypersaline environments where it can tolerate extremes of heat, light, pH, and up to saturating concentrations of salt. The D. salina Bardawil isolate (UTEX LB 2538) was found in a salt pond near the Bardawil Lagoon on the Sinai peninsula in 1976. This isolate of D. salina is the richest natural source of beta-carotene, a highly valuable commercial product. This accession includes an RNA-Seq analysis of D. salina Bardawil cultures grown in iron-replete (1.5 µM) or iron-deficient (0 µM) media.
Project description:We set out to investigate the genetic adaptions of the known marine fungus Paradendryphiella salina CBS112865 to the degradation of brown macro-algae, expecting to find a repertoire of carbohydrate active enzymes highly specialized to the degradation of algal polysaccharides. We performed whole genome, transcriptome sequencing and shotgun proteomic analysis of the secretome of P. salina growing on three species of brown algae and under carbon starvation. The genome comparison to close terrestrial fungal relatives, revealed P. salina to have a similar, but reduced carbohydrate active enzyme (CAZyme) profile, except for the presence of three putative alginate lyase 7 genes, most likely acquired via ancient horizontal gene transfer event from a marine bacterium and a polysaccharide lyase 8 gene with similarity to ascomycete chondroitin AC lyases. The proteomic analysis revealed both PL7 and PL8 enzymes to be highly abundant in the algal fermentations together with enzymes necessary for degradation of laminarin, cellulose, lipids and peptides. Our findings indicate that the base CAZyme repertoire of saprobic and plant pathogenic ascomycetes with the necessary addition of alginate lyases provide the fungi with the enzymatic capabilities to thrive on brown algae polysaccharides and even cope with the algal defense mechanisms.
Project description:Light quality is an important abiotic factor that affects growth and development of photosynthetic organism. In this study, D. salina was exposed to red (660 nm) and blue light (450 nm), and cell growth, pigments, and transcriptome were analyzed. The RNA of D. salina was sequenced and transcriptomic response of algal cells after transitioning from white light to red and blue light was investigated. Genes encoding for enzymes involved in photosynthesis were down-regulated, whereas genes involved in the metabolism of carotenoid were up-regulated. Genes encoding for photoprotective enzymes related to reactive oxygen species scavenging were up-regulated under both red and blue light. The present transcriptomic study would assist in the comprehensive understanding of carotenoid biosynthesis of D. salina.
Project description:The unicellular green alga Dunaliella salina is an attractive model organism for studying photoacclimation responses. Changes in irradiance levels during cell growth affect the organization and structure of the photosystem and the pigments composition. We sequenced the RNA of D. salina to investigate the transcriptomic response of the organism after transitioning from normal light conditions to higher light intensity. Specific transcripts encoding for enzymes involved in photosynthesis were down-regulated, whereas genes involved in the metabolism of carotenoid and triacylglycerol were up-regulated. Genes encoding for photoprotective enzymes related to reactive oxygen species (ROS) scavenging and to the xanthophyll cycle were also up-regulated at higher irradiance levels. The present transcriptomic study would assist in the comprehensive understanding of photoacclimation mechanisms of D. salina.