Department of Plant and Soil Science, University of Kentucky, Lexington, KY, USA.
Plant Biotechnol J. 2010 Feb;8(2):184-95. doi: 10.1111/j.1467-7652.2009.00476.x.
Vernolic acid (cis-12-epoxy-octadeca-cis-9-enoic acid) is valuable as a renewable chemical feedstock. This fatty acid can accumulate to high levels in the seed oil of some plant species such as Vernonia galamensis and Stokesia laevis which are unsuitable for large-scale production. A cost-effective alternative for production of epoxy fatty acids is to genetically engineer its biosynthesis in commercial oilseeds. An epoxygenase cDNA (SlEPX) responsible for vernolic acid synthesis and two acyl-CoA : diacylglycerol acyltransferase cDNAs (VgDGAT1 and VgDGAT2) catalysing triacylglycerol (TAG) formation were cloned from developing seeds of S. laevis and V. galamensis. Co-expression of SlEPX and VgDGAT1 or VgDGAT2 greatly increases accumulation of vernolic acid both in petunia leaves and soybean somatic embryos. Seed-specific expression of VgDGAT1 and VgDGAT2 in SlEPX mature soybean seeds results in vernolic acid levels of approximately 15% and 26%. Both DGAT1 and DGAT2 increase epoxy fatty acid accumulation with DGAT2 having much greater impact.
vernolic 酸（顺式-12-环氧-十八碳-顺式-9-烯酸）是一种有价值的可再生化学原料。这种脂肪酸可以在某些植物物种的种子油中积累到很高的水平，例如 Vernonia galamensis 和 Stokesia laevis，它们不适合大规模生产。生产环氧化脂肪酸的一种具有成本效益的替代方法是在商业油料作物中通过基因工程来合成其生物合成。负责 vernolic 酸合成的环氧合酶 cDNA（SlEPX）和催化三酰基甘油（TAG）形成的两种酰基辅酶 A：二酰基甘油酰基转移酶 cDNA（VgDGAT1 和 VgDGAT2）从 S. laevis 和 V. galamensis 的发育种子中克隆。SlEPX 与 VgDGAT1 或 VgDGAT2 的共表达大大增加了矮牵牛叶片和大豆体细胞胚中 vernolic 酸的积累。VgDGAT1 和 VgDGAT2 在 SlEPX 成熟大豆种子中的种子特异性表达导致 vernolic 酸水平约为 15%和 26%。DGAT1 和 DGAT2 都增加了环氧化脂肪酸的积累，DGAT2 的影响要大得多。
