Discovery of genes for production of biofuels through transcriptome sequencing of Dunaliella parva

Compared with first generation plant-based biofuels, microalgae have potential advantages as feedstock for biofuel production. However, the genome sequences were insufficient in non-model microalgae with potential for biofuel production, which limited the development of genetic engineering of these microalgae. Here we described the de novo transcriptome sequencing and assembly for the halophilic green alga Dunaliella parva and identified important pathways, genes and transcription factor gene wri1 involved in biofuel production. The Illumina Hiseq 2000 platform was applied to D. parva transcriptome sequencing, which produced 26,304,060 (assembled into 60,883 contigs) and 26,797,446 (assembled into 55,236 contigs) high quality reads in samples SCH-5.0 mMA (control sample) and SCH-0.5 mMA (nitrogen limitation sample) respectively. Assembled contigs were subjected to Blastx search and annotated with NCBI non-redundant protein database, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes orthology identifiers. These analyses obtained the majority of genes involved in the biosynthesis and degradation of lipid and starch in D. parva. In addition, we have identified numerous differentially expressed genes, especially important transcription factor gene wri1 (GenBank KR185335) and studied differential expression of wri1 between control and nitrogen limitation sample, which provided foundation for illuminating the regulation mechanism of lipid biosynthesis induced by nitrogen limitation.