Abstract
WRINKLED1 (WRI1) is a member of the APETALA2 (AP2)/EREBP (ethylene response element binding protein) transcription factor family and has been shown to be one of the important transcription regulators involved in the oil biosynthesis pathway. To investigate the role of WRI1 in the regulation of oil synthesis in Auxenochlorella protothecoides (A. protothecoides), the wri1 gene, cloned from Dunaliella parva (D. parva), was introduced and expressed in A. protothecoides. We discovered that the oil content of the genetically modified algae strain (A. protothecoides-Dpwri1) increased by 38.3% compared to the wild strain. The transcriptome analysis revealed that the expression of Dpwri1 in A. protothecoides up-regulated the expression of glucose-6-phosphate isomerase (GPI), 3-phosphoglyceraldehyde dehydrogenase (GAPDH), phosphoenolpyruvate carboxykinase (PEPCK), diacylglycerol acyltransferase (DGAT), which involved in glycolytic pathway and triglyceride synthesis pathway respectively, resulting in the flow of carbon to the synthesis of lipids. In addition, the expression of acyl-CoA oxidase (ACOX) and acetyl-CoA acetyltransferase 1(ACAT1) were down-regulated, which is beneficial to the accumulation of lipids in cells. This study reveals the important role of the exogenous WRI1 transcription factor in regulating the accumulation of lipids in A. protothecoides, which is of guiding significance for the construction of high-yield oil-producing strains.