Molecular Mechanisms of Changes in Contents of Organic Compounds Based on Transcriptome and Metabolome in Dpwri1 Transgenic Dunaliella parva.

The halophilic green alga Dunaliella parva (D. parva) is of huge industrial interest for production of biofuels and high value-added products such as carotenoid. Our previous study indicated that D. parva WRINKLED1 (Dpwri1) was a crucial transcription factor regulating lipid synthesis in D. parva, and found that carotenoid content increased by 0.80 mg/g dry weight (DW), starch content decreased by 11.17 mg/g DW, lipid content had an absolute increase of 23.11% (from 50.40% DW to 73.51% DW) in transgenic D. parva overexpressing Dpwri1 (sample Wri1) compared with control (sample C). However, the mechanisms underlying the changes of organic matter contents (starch content, lipid content, carotenoid content) remain unclear. Integrative analyses of transcriptome and metabolome were used to explain the underlying mechanisms in Dpwri1 transgenic D. parva. The result indicated that differentially expressed genes related to starch metabolism (genes encoding oligo-1,6-glucosidase and glycogen phosphorylase), glycolysis (genes encoding glyceraldehyde-3-phosphate dehydrogenase, pyruvate kinase and glycerate 3-kinase) and carotenoid metabolism (genes encoding phytoene desaturase, zeta-carotene desaturase, lycopene beta-cyclase and beta-carotene 3-hydroxylase), and differentially expressed metabolites related to lipid metabolism might contribute to the increase in contents of lipid and carotenoid, and the decrease of starch content. This study laid a good foundation for understanding the mechanisms related to the effects of Dpwri1 overexpression.