Characterization of type-2 diacylglycerol acyltransferases in Haematococcus lacustris reveals their functions and engineering potential in triacylglycerol biosynthesis

Abstract Background Haematococcus lacustris is an ideal source of astaxanthin (AST), which stored in oil bodies containing esterified AST (EAST) and triacylglycerol (TAG). Diacylglycerol acyltransferases (DGATs) catalyze the last step acyl-CoA-dependent TAG biosynthesis are also considered as crucial enzymes involved EAST H. lacustris. Previous studies have identified four putative DGAT2-encoding genes , only HpDGAT2D allowed recovery biosynthesis, but engineering potential HpDGAT2s remains ambiguous. Results Five DGAT2 ( HpDGAT2A HpDGAT2B HpDGAT2C HpDGAT2E ) were . Transcription analysis showed that expression levels markedly increased under high light nitrogen deficient conditions with distinct patterns, led to significant accumulation. Functional complementation demonstrated HpDGAT2A, HpDGAT2B, HpDGAT2D, had capacity restore synthesis a TAG-deficient yeast strain (H1246) showing large difference enzymatic activity. Fatty acid (FA) profile assays revealed HpDGAT2E, not preferred monounsaturated fatty acyl-CoAs (MUFAs) for cells, preference polyunsaturated (PUFAs) based on their feeding strategy. The heterologous Arabidopsis thaliana Chlamydomonas reinhardtii significantly content obviously promoted MUFAs PUFAs contents. Conclusions Our study represents systematic work characterization by integrating AST/TAG accumulation, functional complementation, yeast, plants, algae. These results (1) update gene models (2) prove HpDGAT2s, (3) show strong PUFAs, (4) offer target modulate using genetic methods.