Department of Plant and Soil Science, University of Kentucky, KY 40546-0312, USA.
Metab Eng. 2012 Jan;14(1):29-38. doi: 10.1016/j.ymben.2011.11.004. Epub 2011 Nov 12.
Plant oils can be useful chemical feedstocks such as a source of epoxy fatty acids. High seed-specific expression of a Stokesia laevis epoxygenase (SlEPX) in soybeans only results in 3-7% epoxide levels. SlEPX-transgenic soybean seeds also exhibited other phenotypic alterations, such as altered seed fatty acid profiles, reduced oil accumulation, and variable protein levels. SlEPX-transgenic seeds showed a 2-5% reduction in total oil content and protein levels of 30.9-51.4%. To address these pleiotrophic effects of SlEPX expression on other traits, transgenic soybeans were developed to co-express SlEPX and DGAT (diacylglycerol acyltransferase) genes (VgDGAT1 & 2) isolated from Vernonia galamensis, a high accumulator of epoxy fatty acids. These side effects of SlEPX expression were largely overcome in the DGAT co-expressing soybeans. Total oil and protein contents were restored to the levels in non-transgenic soybeans, indicating that both VgDGAT1 and VgDGAT2 could complement the disrupted phenotypes caused by over-expression of an epoxygenase in soybean seeds.
植物油脂可以作为环氧脂肪酸的来源，是一种有用的化工原料。在大豆中高度特异性表达 Stokesia laevis 环氧化物酶（SlEPX）只会导致 3-7%的环氧化物水平。SlEPX 转基因大豆种子还表现出其他表型改变，如改变种子脂肪酸谱、减少油脂积累和蛋白质水平变化。SlEPX 转基因种子的总油含量和蛋白质水平分别降低了 2-5%和 30.9-51.4%。为了解决 SlEPX 表达对其他性状的多效性影响，开发了共表达 SlEPX 和 DGAT（二酰基甘油酰基转移酶）基因（来自 Vernonia galamensis 的 VgDGAT1 和 VgDGAT2）的转基因大豆，Vernonia galamensis 是环氧脂肪酸的高积累者。在共表达 DGAT 的大豆中，SlEPX 表达的这些副作用在很大程度上得到了克服。总油和蛋白质含量恢复到非转基因大豆的水平，表明 VgDGAT1 和 VgDGAT2 都可以弥补在大豆种子中过表达环氧化物酶引起的破坏表型。
