超表达MucACP-Δ9脱氢酶对烟草叶组织油脂合成的影响

Effect of overexpression of MucACP-Δ9 desaturase on lipid synthesis in tobacco leaves tissuse

棕榈油酸（C16：1Δ9）和顺式十八碳烯酸（C18：1Δ11）等ω-7脂肪酸具有重要的食品营养、医药保健与工业应用价值。本文构建了来自富含ω-7脂肪酸的猫爪藤（Macfadyena ungui s-cati）ACP-Δ9脱氢酶基因（Muc ACP-Δ9D）的植物组成型表达载体,农杆菌介导转化烟草叶盘,获得转基因植株。超表达且定位于质体的Muc ACP-Δ9D使烟草叶片脂肪酸组分发生显著改变,饱和的棕榈酸（C16：0）含量下降30%-50%,2种ω-7脂肪酸（C16：1Δ9和C18：1Δ11）含量均显著增加,分别由对照的微含量提升至16.4%-20.4%和9.0%。棕榈酸与这2种ω-7脂肪酸含量之间呈极显著负相关。另外,C18：2与C18：3多不饱和脂肪酸在转基因烟草叶片中的含量均显著减少,二者含量与C16：1Δ9及C18：1Δ11的含量亦呈负相关关系。这表明导入的异源Muc ACP-Δ9D能在烟草细胞质体内高效催化ACP-C16：0生成ACP-C16：1Δ9,ACP-C16：1Δ9进一步延伸产生C18：1Δ11,最终实现烟草叶片中ω-7脂肪酸的合成与富集,使ω-7脂肪酸从对照极低含量提高到25.4%-29.4%。此外,Muc ACP-Δ9D基因在烟叶组织超表达,对烟草植物生长发育及种子发芽等表型未构成不良影响。本研究为利用以非粮食作物、生物量巨大的烟草营养器官为平台生产优质脂肪酸提供新的技术路径和优异种质资源。

Plant oils enriched in ω-7 monounsaturated fatty acids,including palmitoleic acid（16：1？9） and cis-vaccenic acid（18：1？11）,have nutraceutical and industrial value for polyethylene production and biofuels.Muc ACP-Δ9D gene identified from Macfadyena unguis-cati was cloned into binary overexpression vector,which was transformed into discs of tobacco by Agrobacterium tumefaciens-mediated method,and obtained transgenic plants overexpressing Muc ACP-Δ9D gene.Western blotting showed that gene expression was located in chloroplast.Notablly,the composition of fatty acids in transgenic tobacco leaves lipid was different to wild type,including the content of C16：0 saturated fatty acid decreasing 30%–50%,the ω-7 of C16：1Δ9 and C18：1Δ11 increasing 16.4%–20.4% and 9.0% respectively,and statistical analysis showed that the content of ω-7 was strong negative correlation to the content of C16：0.The content of C18：2 and C18：3 polyunsaturated fatty acids in transgenic plants were reduced significantly,and statistical analysis showed that the content of two polyunsaturated fatty acids was negative correlation to the content of ω-7.All of these data showed that Muc ACP-Δ9D enzyme desaturated C16：0 to C16：1Δ9 with high acticity,and C16：1Δ9 was elongated to C18：1Δ11.At last,the content of C16：1Δ9 and C18：1Δ11 increased to 25.4%–29.4% totally compared to little in wild type.In addition,Muc ACP-Δ9D gene overexpression had no adverse effects on the growth and development of plants,germination of seeds.The study would provide a new technology system and plant germplasm resources for vegetative tissuse of non-crops with high-biomass as production platform for special fatty acids.