Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
J Plant Physiol. 2013 Oct 15;170(15):1360-6. doi: 10.1016/j.jplph.2013.04.019. Epub 2013 Jun 21.
Linoleic acid (LA, C18:2) and α-linolenic acid (ALA, C18:3) are polyunsaturated fatty acids (PUFAs) and major storage compounds in plant seed oils. Microsomal ω-6 and ω-3 fatty acid (FA) desaturases catalyze the synthesis of seed oil LA and ALA, respectively. Jatropha curcas L. seed oils contain large proportions of LA, but very little ALA. In this study, two microsomal desaturase genes, named JcFAD2 and JcFAD3, were isolated from J. curcas. Both deduced amino acid sequences possessed eight histidines shown to be essential for desaturases activity, and contained motif in the C-terminal for endoplasmic reticulum localization. Heterologous expression in Saccharomyces cerevisiae and Arabidopsis thaliana confirmed that the isolated JcFAD2 and JcFAD3 proteins could catalyze LA and ALA synthesis, respectively. The results indicate that JcFAD2 and JcFAD3 are functional in controlling PUFA contents of seed oils and could be exploited in the genetic engineering of J. curcas, and potentially other plants.
亚油酸（LA，C18:2）和α-亚麻酸（ALA，C18:3）是多不饱和脂肪酸（PUFA），也是植物种子油的主要储存化合物。微粒体 ω-6 和 ω-3 脂肪酸（FA）去饱和酶分别催化种子油 LA 和 ALA 的合成。麻疯树种子油含有大量的 LA，但几乎没有 ALA。在这项研究中，从麻疯树中分离出了两个微粒体去饱和酶基因，分别命名为 JcFAD2 和 JcFAD3。两个推导的氨基酸序列都含有八个组氨酸，这些组氨酸对于去饱和酶的活性是必需的，并且在 C 末端含有内质网定位的基序。在酿酒酵母和拟南芥中的异源表达证实，分离的 JcFAD2 和 JcFAD3 蛋白可以分别催化 LA 和 ALA 的合成。结果表明，JcFAD2 和 JcFAD3 能够控制种子油中多不饱和脂肪酸的含量，可用于麻疯树及其他植物的遗传工程。
