PDF(Pubmed)
Abstract：
UNASSIGNED: The African oil palm (Elaeis guineensis Jacq.) is the predominant oil crop in the world. In addition to triacylglycerols, crude palm oil (CPO) extracted from the mesocarp of the fruits, contains high amounts of provitamin A (carotenes) and vitamin E (tocochromanols). Because of their unsaturated nature, the carotenes are prone to oxidation and therefore are in part limiting for the shelf life of CPO.
UNASSIGNED: A tree with unusual toochromanol composition was identified by HPLC screening of the mesocarp of wild trees. Polymorphisms in a candidate gene were identified by DNA sequencing. The candidate protein was heterologously expressed in Escherichia coli coli and Arabidopsis thaliana to test for enzyme activity. Oxidative stability of the CPO was studied by following carotene degradation over time.
UNASSIGNED: In the present study, a wild Oil Palm tree (C59) from Cameroon was identified that lacks α-tocopherol and α-tocotrienol and instead accumulates the respective γ forms, suggesting that the activity of γ-tocopherol methyltransferase (VTE4) was affected. Sequencing of the VTE4 locus in the genome of plant C59 identified a G/C polymorphism that causes the exchange of a highly conserved tryptophan at position 290 with serine. The W290S exchange renders the VTE4 enzyme inactive, as shown after expression in Escherichia coli and Arabidopsis thaliana. The oxidative stability of carotenes in the mesocarp of the wild palm C59 was enhanced compared with control accessions. Furthermore, supplementation of commercial palm oil with different tocochromanols showed that γ-tocotrienol exerts a stronger effect during the protection of carotenes against oxidation than α-tocotrienol.
UNASSIGNED: Therefore, the introduction of the high γ-tocotrienol trait into elite breeding lines represents a potent strategy to protect carotenes against oxidation and extend the shelf life of CPO, hence allowing the development of a value added high-carotene CPO to be used to fight against vitamin A deficiency.
UNASSIGNED: A tree with unusual toochromanol composition was identified by HPLC screening of the mesocarp of wild trees. Polymorphisms in a candidate gene were identified by DNA sequencing. The candidate protein was heterologously expressed in Escherichia coli coli and Arabidopsis thaliana to test for enzyme activity. Oxidative stability of the CPO was studied by following carotene degradation over time.
UNASSIGNED: In the present study, a wild Oil Palm tree (C59) from Cameroon was identified that lacks α-tocopherol and α-tocotrienol and instead accumulates the respective γ forms, suggesting that the activity of γ-tocopherol methyltransferase (VTE4) was affected. Sequencing of the VTE4 locus in the genome of plant C59 identified a G/C polymorphism that causes the exchange of a highly conserved tryptophan at position 290 with serine. The W290S exchange renders the VTE4 enzyme inactive, as shown after expression in Escherichia coli and Arabidopsis thaliana. The oxidative stability of carotenes in the mesocarp of the wild palm C59 was enhanced compared with control accessions. Furthermore, supplementation of commercial palm oil with different tocochromanols showed that γ-tocotrienol exerts a stronger effect during the protection of carotenes against oxidation than α-tocotrienol.
UNASSIGNED: Therefore, the introduction of the high γ-tocotrienol trait into elite breeding lines represents a potent strategy to protect carotenes against oxidation and extend the shelf life of CPO, hence allowing the development of a value added high-carotene CPO to be used to fight against vitamin A deficiency.
摘要：
■非洲油棕（ElaeisguineensisJacq。)是世界上主要的油料作物。除了三酰甘油，从水果的中果皮中提取的粗棕榈油（CPO），含有大量的维生素原A（胡萝卜素）和维生素E（生育色酚）。由于它们的不饱和性质，胡萝卜素易于氧化,因此部分限制了CPO的保质期。
■通过HPLC筛选野生树木的中果皮来鉴定具有不寻常的toochronanol组成的树木。通过DNA测序鉴定候选基因中的多态性。在大肠杆菌和拟南芥中异源表达候选蛋白以测试酶活性。通过随着时间的推移胡萝卜素降解来研究CPO的氧化稳定性。
■在本研究中，来自喀麦隆的野生油棕榈树（C59）被鉴定为缺乏α-生育酚和α-生育三烯酚，而是积累了各自的γ形式，表明γ-生育酚甲基转移酶（VTE4）的活性受到影响。植物C59基因组中VTE4基因座的测序鉴定了G/C多态性，该多态性导致第290位高度保守的色氨酸与丝氨酸交换。W290S交换使VTE4酶失活，如在大肠杆菌和拟南芥中表达后所示。与对照材料相比，野生棕榈C59的中果皮中胡萝卜素的氧化稳定性增强。此外，用不同的生育酚补充商品棕榈油表明，γ-生育三烯酚在保护胡萝卜素免受氧化过程中比α-生育三烯酚具有更强的作用。
■因此，将高γ-生育三烯酚性状引入优良育种系代表了一种有效的策略来保护胡萝卜素免受氧化并延长CPO的保质期，因此，允许开发高附加值的高胡萝卜素CPO用于对抗维生素A缺乏症。
■通过HPLC筛选野生树木的中果皮来鉴定具有不寻常的toochronanol组成的树木。通过DNA测序鉴定候选基因中的多态性。在大肠杆菌和拟南芥中异源表达候选蛋白以测试酶活性。通过随着时间的推移胡萝卜素降解来研究CPO的氧化稳定性。
■在本研究中，来自喀麦隆的野生油棕榈树（C59）被鉴定为缺乏α-生育酚和α-生育三烯酚，而是积累了各自的γ形式，表明γ-生育酚甲基转移酶（VTE4）的活性受到影响。植物C59基因组中VTE4基因座的测序鉴定了G/C多态性，该多态性导致第290位高度保守的色氨酸与丝氨酸交换。W290S交换使VTE4酶失活，如在大肠杆菌和拟南芥中表达后所示。与对照材料相比，野生棕榈C59的中果皮中胡萝卜素的氧化稳定性增强。此外，用不同的生育酚补充商品棕榈油表明，γ-生育三烯酚在保护胡萝卜素免受氧化过程中比α-生育三烯酚具有更强的作用。
■因此，将高γ-生育三烯酚性状引入优良育种系代表了一种有效的策略来保护胡萝卜素免受氧化并延长CPO的保质期，因此，允许开发高附加值的高胡萝卜素CPO用于对抗维生素A缺乏症。
