三角褐指藻是一种高油脂含量的海洋单细胞硅藻，是目前研究微藻油脂合成途径的模式藻种之一。三角褐指藻油脂的主要成分是甘油三脂（TAG），二酯酰甘油酰基转移酶（DGAT）是TAG合成的限速酶，目前发现该藻含有多个的DGAT基因，但TAG合成机制尚不明确。申请人在三角褐指藻基因组上发现了一个可能编码蜡酯合成酶/二酯酰甘油酰基转移酶（WS/DGAT）的基因，这是在藻类细胞中发现的第一个WS/DGAT双功能酶基因。这种原核型结构的基因在三角褐指藻中是否能够表达并具有相应的功能？其表达对甘油三脂和蜡酯合成与积累有什么样的影响？该基因与三角褐指藻已知DGAT基因是否存在协同作用？.为了探明以上问题，本项目拟通过在缺陷型酵母中异源表达WS/DGAT基因，验证其功能；通过实时荧光定量法检测三角褐指藻中该基因的表达模式及与已知DGAT基因的相互关系，并通过构建过表达突变株进一步验证其在油脂合成中的作用。

The diatom Phaeodactylum tricornutum is a microalga with high containing of lipid. P. tricornutum oil contains large amounts of triacylglycerol (TAG) of total lipids under stress conditions, suggesting that the enzymes responsible for TAG formation are active in P. tricornutum. Diacylglycerol acyltransferase (DGAT) plays a pivotal role in TAG formation. There are seven proposed diacylglycerol acyltransferase genes found in P. tricornutum genome, three of which were confirmed for the functions. Recently our team found a novel gene in P. tricornutum genome which may encode a wax ester synthase/diacylglycerol acyltransferase (WS/DGAT). It is the first WS/DGAT described thus far from microalgae. It is urgent to know whether the gene could express active protein as a prokaryotic gene construct, whether the enzyme could enhance wax ester or TAG synthesis, and the relationship of this enzyme with the other DGATs in P. tricornutum..For these above questions, this project is going to testify P. tricornutum WS/DGAT-like gene function by expression in the yeast Saccharomyces cerevisiae TAG-deficient mutant; meanwhile the expression pattern of this gene and the relationship with known DGATs in P tricornutum, will be conducted by real-time PCR; A mutant P. tricornutum with the WS/DGAT-like gene overexpression will be constructed for further confirmation of the WS/DGAT function.