Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA.
Plant Biotechnol J. 2023 Mar;21(3):497-505. doi: 10.1111/pbi.13966. Epub 2022 Dec 1.
Reducing the saturate content of vegetable oils is key to increasing their utility and adoption as a feedstock for the production of biofuels. Expression of either the FAT5 16 : 0-CoA desaturase from Caenorhabditis elegans, or an engineered cyanobacterial 16 : 0/18 : 0-glycerolipid desaturase, DES9*, in seeds of Arabidopsis (Arabidopsis thaliana) substantially lowered oil saturates. However, because pathway fluxes and regulation of oil synthesis are known to differ across species, translating this transgene technology from the model plant to crop species requires additional investigation. In the work reported here, we found that high expression of FAT5 in seeds of camelina (Camelina sativa) provided only a moderate decrease in saturates, from 12.9% of total oil fatty acids in untransformed controls to 8.6%. Expression of DES9* reduced saturates to 4.6%, but compromised seed physiology and oil content. However, the coexpression of the two desaturases together cooperatively reduced saturates to only 4.0%, less than one-third of the level in the parental line, without compromising oil yield or seedling germination and establishment. Our successful lowering of oil saturates in camelina identifies strategies that can now be integrated with genetic engineering approaches that reduce polyunsaturates to provide optimized oil composition for biofuels in camelina and other oil seed crops.
降低植物油的饱和度是提高其作为生物燃料生产原料的可用性和采用率的关键。在拟南芥种子中表达来自秀丽隐杆线虫的 FAT5 16:0-CoA 去饱和酶，或经过工程改造的蓝藻 16:0/18:0-甘油脂去饱和酶 DES9*，可显著降低油脂饱和度。然而，由于途径通量和油脂合成的调控在不同物种之间已知存在差异，因此需要对这种转基因技术从模式植物到作物物种进行进一步的研究。在本研究中，我们发现，FAT5 在荠蓝种子中的高表达仅适度降低了饱和度，从未转化对照的总油脂肪酸的 12.9%降低到 8.6%。DES9*的表达将饱和度降低至 4.6%，但损害了种子的生理学和油含量。然而，两种去饱和酶的共表达协同地将饱和度降低至仅 4.0%，不到亲本系的三分之一，而不影响油产量或幼苗的发芽和建立。我们在荠蓝中成功降低了油脂饱和度，确定了可以与降低多不饱和脂肪酸的遗传工程方法相结合的策略，从而为荠蓝和其他油料作物的生物燃料提供优化的油成分。
