Cloning And Expressing Of Lysophosphatidic Acid Acyltransferase Family Genes From Brassica Napus L.

Rapeseed is one of the most important oil crops in China and worldwide, improving the seed oil contents and quality was considered to be the most focused issues in the past decades. Exploring the key genes relative to the synthesis and accumulation of fatty acid will be helpful to the research of improving seed oil content and quality.In this study, one of the oil metabolism gene lysophosphatidic acid acyltransferase (LPAT) was isolated from developing seeds of Brassica napus with high oil content. Eleven copy genes belonging to LPAT family were acquired and named as follow, BnLPAT1-LP2.2、BnLPAT1-LP4.3、BnLPAT1-LP5.3、BnLPAT1-LP5.4、BnLPAT2-A7、 BnLPAT2-A9、BnLPAT2-C7、BnLPAT2-C8、BnLPAT3、BnLPAT4.2、BnLPAT5.2. Four copies locate in Chloroplast and belonging to plastid type LPAT. Other copies of LPAT locate in endoplasmic reticulum and belonging to microsomal type LPAT. In vitro complementation test demonstrates that plastid type LPAT possess acyltransferase activity in E coli. With the development of seeds in silique, the expression levels of BnLPAT1, BnLPAT2 and BnLPAT5.2 also elevated at the same time. Overexpress all the genes in Arabidopsis respectively demonstrated that the transgenic lines of BnLPAT2-A7、BnLPAT2-C7、 BnLPAT2-C8 improved the seed linolenic acid 30% compared with wide type. Little changes of linolenic acid content were obversed in the overespression lines of BnLPAT2-A9 indicated that different copy of the genes may possess different functions even though they belong to same gene family. In the BnLPAT4.2 overexpression lines, oleic acid was observed increasing over 15% compared with wild type simultaneous with little drop of C20:1. The oil contents of BnLPAT5.2 overexpression lines elevated 5% compared with wild type and germination rate were not affected in the transgenic seeds.Those findings will be important in improvement of oil content and linolenic acid synthesis and accumulation in seeds in the future.In this study, the main innovative pionts are as follow,1. We developed high efficient InGate methods which could be applied in vector reconstruction and an efficient methods using a red fluorescent protein DsRed in screening single copy transgenic Arabidopsis.2. This is the first report that LPAT2 can improve the components of linolenic acid in seed oil.3. We found that LPAT4.2 elevated the oleic acid accumulation in Arabidopsiss.4. This the first report of LPAT5 can elevate the oil contents in Arabidopsis seeds.