Department of Biological Sciences, BioDiscovery Institute, University of North Texas, Denton, TX, USA.
Center for Plant Science Innovation and Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, USA.
Plant Biotechnol J. 2021 Jun;19(6):1268-1282. doi: 10.1111/pbi.13557. Epub 2021 Feb 17.
Upland cotton (Gossypium hirsutum L.) is an economically important multi-purpose crop cultivated globally for fibre, seed oil and protein. Cottonseed oil also is naturally rich in vitamin E components (collectively known as tocochromanols), with α- and γ-tocopherols comprising nearly all of the vitamin E components. By contrast, cottonseeds have little or no tocotrienols, tocochromanols with a wide range of health benefits. Here, we generated transgenic cotton lines expressing the barley (Hordeum vulgare) homogentisate geranylgeranyl transferase coding sequence under the control of the Brassica napus seed-specific promoter, napin. Transgenic cottonseeds had ~twofold to threefold increases in the accumulation of total vitamin E (tocopherols + tocotrienols), with more than 60% γ-tocotrienol. Matrix assisted laser desorption ionization-mass spectrometry imaging showed that γ-tocotrienol was localized throughout the transgenic embryos. In contrast, the native tocopherols were distributed unequally in both transgenic and non-transgenic embryos. α- Tocopherol was restricted mostly to cotyledon tissues and γ-tocopherol was more enriched in the embryonic axis tissues. Production of tocotrienols in cotton embryos had no negative impact on plant performance or yield of other important seed constituents including fibre, oil and protein. Advanced generations of two transgenic events were field grown, and extracts of transgenic seeds showed increased antioxidant activity relative to extracts from non-transgenic seeds. Furthermore, refined cottonseed oil from the two transgenic events showed 30% improvement in oxidative stability relative to the non-transgenic cottonseed oil. Taken together, these materials may provide new opportunities for cottonseed co-products with enhanced vitamin E profile for improved shelf life and nutrition.
陆地棉（Gossypium hirsutum L.）是一种经济上重要的多用途作物，在全球范围内种植用于纤维、种子油和蛋白质。棉籽油也天然富含维生素 E 成分（统称为生育三烯酚），其中 α-和 γ-生育酚几乎构成了所有的维生素 E 成分。相比之下，棉籽几乎不含或不含生育三烯酚，生育三烯酚具有广泛的健康益处。在这里，我们通过控制 Brassica napus 种子特异性启动子 napin 生成了表达大麦（Hordeum vulgare）全反式-4-羟基-2-甲基-2-戊烯基-4-己烯酰基辅酶 A 异构酶编码序列的转基因棉花品系。转基因棉籽中总维生素 E（生育酚+生育三烯酚）的积累增加了约两倍至三倍，其中 γ-生育三烯酚超过 60%。基质辅助激光解吸电离质谱成像显示，γ-生育三烯酚在整个转基因胚胎中均有分布。相比之下，天然生育酚在转基因和非转基因胚胎中的分布不均等。α-生育酚主要局限于子叶组织，而 γ-生育酚在胚胎轴组织中更为丰富。在棉花胚胎中产生生育三烯酚对植物性能或其他重要种子成分（包括纤维、油和蛋白质）的产量没有负面影响。两个转基因事件的高级代在田间种植，并且从转基因种子中提取的提取物表现出比从非转基因种子中提取的提取物更高的抗氧化活性。此外，与非转基因棉籽油相比，来自两个转基因事件的精炼棉籽油的氧化稳定性提高了 30%。综上所述，这些材料可能为富含维生素 E 的棉籽提供新的机会，以提高货架期和营养价值。
