Liu Guo, Wu Zhihua, Shang Xiuhua, Peng Yan, Gao Liqiong
Research Institute of Fast-Growing Trees, Chinese Academy of Forestry, 30 Mid Renmin Avenue, Zhanjiang 524022, China.
Genes (Basel). 2022 Feb 28;13(3):450. doi: 10.3390/genes13030450.
The ω-3 fatty acid desaturase () gene encodes a rate-limiting enzyme in the synthesis of α-linolenic acid. In this study, homologous cloning was used to obtain the full-length sequence of the gene of . The full-length DNA sequence was 1871 bp long, with 8 exons and 7 introns. The structural analysis of the amino acid sequence revealed that the PvFAD3 protein contained three histidine-conserved regions and an endoplasmic reticulum retention signal. The real-time reverse transcription-polymerase chain reaction performed for determining the expression patterns of the gene in different tissues of showed that expression was highly expressed in the fast oil accumulation stage of seed. The analysis of subcellular localization assay in epidermal cells of tobacco () leaves showed that the PvFAD3 protein was mainly localized in the endoplasmic reticulum. Seed-specific overexpression vectors were constructed, and -mediated genetic transformation was performed to obtain transgenic tobacco plants overexpressing . The results of fatty acid assays performed using harvested seeds showed a significant increase in α-linolenic acid content, a dramatic decrease in linoleic acid content, and an obvious increase in oil content in transgenic tobacco seeds. Collectively, the gene of was confirmed as a key enzyme gene for α-linolenic acid synthesis; thus, indicating that the gene can be used for fatty acid fraction improvement in oilseed plants.
ω-3脂肪酸去饱和酶（）基因编码α-亚麻酸合成中的一种限速酶。在本研究中，采用同源克隆法获得了的基因全长序列。DNA全长序列为1871 bp，含8个外显子和7个内含子。氨基酸序列结构分析表明，PvFAD3蛋白包含三个组氨酸保守区和一个内质网滞留信号。通过实时逆转录-聚合酶链反应检测该基因在不同组织中的表达模式，结果显示在种子快速油脂积累阶段高表达。烟草（）叶片表皮细胞亚细胞定位分析表明，PvFAD3蛋白主要定位于内质网。构建种子特异性过表达载体，并通过介导的遗传转化获得过表达的转基因烟草植株。对收获种子进行脂肪酸测定的结果显示，转基因烟草种子中α-亚麻酸含量显著增加，亚油酸含量显著降低，油脂含量明显增加。总体而言，的基因被确认为α-亚麻酸合成的关键酶基因；因此，表明该基因可用于油料作物脂肪酸组分的改良。
