Association of triacylglyceride content and transcript abundance of genes involving in lipid synthesis of nitrogen deficient Phaeodactylum tricornutum

Phaeodactylum tricornutum is a diatom that is rich in lipids. Recently, it has received much attention as a feedstock for biodiesel production. Nitrogen deficiency is widely known to increase the content of neutral lipids （mainly triacylglycerides, or TAGs） of microalgae, including P. tricornutum, but the mechanism is unclear. In this study, we deciphered the correlations between TAG content and nine key enzymatic genes involved in lipid synthesis in P. tricornuturn. After being cultured under nitrogen-free conditions for 0, 4, 24, 48, 72, 120, and 168 h, the TAG contents ofP. tricornutum cells were assayed and the transcript abundances of the target genes were monitored by quantitative real-time PCR. The results show that the abundances of four target gene transcripts （LACS3, G3PDH2, G3PDH3, and G3PDH5） were positively correlated with TAG content, indicating that these genes may be involved in TAG synthesis in P. tricornutum. The findings improve our understanding of the metabolic network and regulation of lipid synthesis and will guide the future genetic improvement of the TAG content ofP. tricornutum.

Phaeodactylum tricornutum is a diatom that is rich in lipids.Recently,it has received much attention as a feedstock for biodiesel production.Nitrogen defi ciency is widely known to increase the content of neutral lipids(mainly triacylglycerides,or TAGs)of microalgae,including P.tricornutum,but the mechanism is unclear.In this study,we deciphered the correlations between TAG content and nine key enzymatic genes involved in lipid synthesis in P.tricornutum.After being cultured under nitrogen-free conditions for 0,4,24,48,72,120,and 168 h,the TAG contents of P.tricornutum cells were assayed and the transcript abundances of the target genes were monitored by quantitative real-time PCR.The results show that the abundances of four target gene transcripts(LACS3,G3PDH2,G3PDH3,and G3PDH5)were positively correlated with TAG content,indicating that these genes may be involved in TAG synthesis in P.tricornutum.The fi ndings improve our understanding of the metabolic network and regulation of lipid synthesis and will guide the future genetic improvement of the TAG content of P.tricornutum.