Transcriptome analysis of <italic>Chlamydomonas reinhardtii</italic> under the co-regulation of three genes

Abstract

In order to study the regulatory roles of multiple genes in microalgal lipid metabolism, a Chlamydomonas reinhardtii strain DLC is constructed with overexpression of DOF transcription regulator and silencing of acs2 and cis1. Transcriptome sequencing and analysis are conducted and 749 differentially expressed genes (DEGs) are identified. According to the result of KEGG (Kyoto encyclopedia of genes and genomes) classification, 51 and 15 DEGs are involved in carbohydrate metabolism and lipid metabolism respectively. These DEGs mainly play key roles in glyceride metabolism, fatty acid degradation, glycolysis/gluconeogenesis and starch and sucrose metabolism. In addition, triacylglycerol (TAG) and starch content are analyzed by BODIPY505/515 fluorescence analysis and absorbance detection, which shows that intracellular TAG increases by 193% as compared with wild-type, while starch content decreases by 45%. These results further indicate that the co-regulation of the three genes not only enhances the lipid anabolism, but also reorients the carbon flux in the saccharide metabolism. The research reveals the molecular mechanism of lipid overproduction under co-regulation of three genes and provides a theoretical reference for the genetic engineering of microalgae lipid production.