College of Agronomy, Hunan Agricultural University, Changsha, 410128, Hunan, China.
Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, Changsha, 410205, Hunan, China.
BMC Plant Biol. 2022 Apr 12;22(1):192. doi: 10.1186/s12870-022-03549-1.
Fatty acid composition and content affect rapeseed oil quality. Fatty acid synthesis-related genes in rapeseed have been studied globally by researchers. Nevertheless, rapeseed oil is mainly composed of seven different fatty acids (FA), and each fatty acid was regulated by different genes. Furthermore, different FA affect each other, which needs continuous and in-depth research to obtain more clear results in Brassica napus.
In this paper, broad-scale miRNA expression profiles were constructed and 21 differentially expressed miRNAs were detected. GO enrichment analysis showed that most up-regulated proteins were involved in transcription factor activity and catalytic activity. KEGG pathway enrichment analysis indicated that 20 pathways involving 36 target genes were enriched, of which the bna00592 pathway may be involved in fatty acid metabolism. The results were verified using a quantitative real-time PCR (RT-qPCR) analysis, we found that the target gene of bna-miR156b > c > g was the OPR (12-oxo-phytodienoic acid reductase). Four copies of OPR gene were found, and the over-expression vectors (pCAMBIA1300-35 s-OPR and pCAMBIA1300-RNAi-OPR) were constructed to verify their functions. In T and T generation, the content of linoleic acid (LA) increased significantly in OE but deceased in OPRi.
This is the first study to provide four copies of the OPR gene that regulates LA metabolism, can be used for the molecular mechanism of LA and optimizing fatty acid profiles in oilseed for breeding programs.
脂肪酸组成和含量影响菜籽油的质量。全球研究人员研究了油菜中与脂肪酸合成相关的基因。然而，菜籽油主要由七种不同的脂肪酸（FA）组成，每种脂肪酸都由不同的基因调控。此外，不同的 FA 相互影响，需要不断深入研究，以在甘蓝型油菜中获得更清晰的结果。
在本研究中，构建了广泛的 miRNA 表达谱，检测到 21 个差异表达的 miRNA。GO 富集分析表明，大多数上调蛋白参与转录因子活性和催化活性。KEGG 通路富集分析表明，涉及 36 个靶基因的 20 个通路富集，其中 bna00592 通路可能参与脂肪酸代谢。使用定量实时 PCR（RT-qPCR）分析进行了验证，发现 bna-miR156b>c>g 的靶基因是 OPR（12-氧代-植二烯酸还原酶）。发现有四个 OPR 基因拷贝，构建了过表达载体（pCAMBIA1300-35s-OPR 和 pCAMBIA1300-RNAi-OPR）来验证其功能。在 T 和 T 代中，OE 中亚油酸（LA）的含量显著增加，而 OPRi 中 LA 的含量则减少。
这是首次研究提供了调节 LA 代谢的四个 OPR 基因拷贝，可用于 LA 及优化油籽脂肪酸图谱的分子机制，以用于育种计划。
