| Elaeis guineensis is a species of palm commonly called oil palm,an economically important tropical oil crop.The content of its palm oil is up to 50%,and it is widely used in chemical,food and bio-energy industries.But as edible vegetable oil,the quality of palm oil is poor,because more than half of fatty acids is palmitic acid,which is harmful to human health.Besides fatty acids,oil palm is also rich in natural vitamin E.Vitamin E in vegetable oil act as antioxidants by effectively preventing polyunsaturated fatty acid from peroxidation,which has become a major research focus of more and more researchers.Today,with the rapid development of biotechnology tools,the research work about oil palm fatty acid and vitamin E has been launched.In this study,we investigated 161 oil palm germplasm resources from Hainan Coconut Research Institute,the contents of fatty acid and vitamin E in oil palm mesocarp were measured.The oil palm germplasm resources were evaluated and some excellent resources were obtained.This work laid the foundation to find important genes,improve palm oil quality and carry out other work.In addition,the functions of EgFatB1,EgFatB2,EgFatB3 and EgHGGT were preliminarily analyzed by reverse genetic approach using Arabidopsis thaliana as a model organism.The main results are as follows:1.There were abundant and continuous variants of fatty acids and vitamin E in 161 different oil palm mesocarp.Most of the traits showed nearly normal distribution,which laid the foundation to find genetic variation by association analysis.2.EgFatB1,EgFatB2 and EgFatB3 genes were overexpressed in wild-type Arabidopsis thaliana.Palmitic acid content of Arabidopsis thaliana seeds expressing EgFatB1 and EgFatB2 transgenic lines were 3.5 and 4.1 times higher than those of wild-type,respectively.The overexpressed EgFatB3 compared to the wild-type led to new generation of lauric acid and myristic acid,while palmitic acid content increased by 1.2 times.We speculate that EgFat B1,EgFatB2,EgFatB3 may play the role on the accumulation of palmitic acid in oil palm mesocarp to some degree,and EgFatB3 could mainly promote the formation of medium chain fatty acids.3.Overexpression of EgHGGT gene in Arabidopsis thaliana resulted to significant increase in Vitamin E content(38% ~73%)compared to the wild-type.The highest content of the newly produced ?-tocotrienol is only 24mg/kg.Compared to other crops,overexpression of EgHGGT gene seems to have limited effect on total vitamin E and ?-tocotrienol levels.4.We investigated the correlation between fatty acid composition and vitamin E content in oil palm mesocarp,it was found that ?-tocopherol,total tocotrienols and total vitamins E was positively or significantly positively correlated with oleic acid,while ?-tocopherol was negatively correlated with palmitic acid.?-tocotrienols,?-tocotrienols,total tocotrienols and total vitamins E were all positively or significantly positively correlated total fatty acid.These results suggest that it is possible to obtain oil palm germplasm resources that combines low palmitic acid,high oleic acid,high oil content and high vitamin E content. |
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