Guan Rui, Li Xueyuan, Hofvander Per, Zhou Xue-Rong, Wang Danni, Stymne Sten, Zhu Li-Hua
Department of Plant Breeding, Swedish University of Agricultural Sciences, PO Box 101, Alnarp, 230 53, Sweden.
Lipids. 2015 Apr;50(4):407-16. doi: 10.1007/s11745-015-4004-1. Epub 2015 Mar 10.
The aim of this study was to evaluate the importance of three enzymes, LPCAT, PDCT and PDAT, involved in acyl turnover in phosphatidylcholine in order to explore the possibility of further increasing erucic acid (22:1) content in Crambe seed oil. The complete coding sequences of LPCAT1-1 and LPCAT1-2 encoding lysophosphatidylcholine acyltransferase (LPCAT), PDCT1 and PDCT2 encoding phosphatidylcholine:diacylglycerol cholinephosphotransferase (PDCT), and PDAT encoding phospholipid:diacylglycerol acyltransferase (PDAT) were cloned from developing Crambe seeds. The alignment of deduced amino acid sequences displayed a high similarity to the Arabidopsis homologs. Transgenic lines expressing RNA interference (RNAi) targeting either single or double genes showed significant changes in the fatty acid composition of seed oil. An increase in oleic acid (18:1) was observed, to varying degrees, in all of the transgenic lines, and a cumulative effect of increased 18:1 was shown in the LPCAT-PDCT double-gene RNAi. However, LPCAT single-gene RNAi led to a decrease in 22:1 accumulation, while PDCT or PDAT single-gene RNAi had no obvious effect on the level of 22:1. In agreement with the abovementioned oil phenotypes, the transcript levels of the target genes in these transgenic lines were generally reduced compared to wild-type levels. In this paper, we discuss the potential to further increase the 22:1 content in Crambe seed oil through downregulation of these genes in combination with fatty acid elongase and desaturases.
本研究的目的是评估参与磷脂酰胆碱中酰基周转的三种酶，即溶血磷脂酰胆碱酰基转移酶（LPCAT）、磷脂酰胆碱：二酰甘油胆碱磷酸转移酶（PDCT）和磷脂：二酰甘油酰基转移酶（PDAT）的重要性，以探索进一步提高海甘蓝种子油中芥酸（22:1）含量的可能性。从发育中的海甘蓝种子中克隆了编码溶血磷脂酰胆碱酰基转移酶（LPCAT）的LPCAT1-1和LPCAT1-2、编码磷脂酰胆碱：二酰甘油胆碱磷酸转移酶（PDCT）的PDCT1和PDCT2以及编码磷脂：二酰甘油酰基转移酶（PDAT）的PDAT的完整编码序列。推导的氨基酸序列比对显示与拟南芥同源物具有高度相似性。表达靶向单基因或双基因的RNA干扰（RNAi）的转基因品系在种子油的脂肪酸组成上表现出显著变化。在所有转基因品系中均观察到油酸（18:1）不同程度的增加，并且在LPCAT-PDCT双基因RNAi中显示出18:1增加的累积效应。然而，LPCAT单基因RNAi导致22:1积累减少，而PDCT或PDAT单基因RNAi对22:1水平没有明显影响。与上述油表型一致，这些转基因品系中靶基因的转录水平与野生型水平相比普遍降低。在本文中，我们讨论了通过下调这些基因并结合脂肪酸延长酶和去饱和酶来进一步提高海甘蓝种子油中22:1含量的潜力。
