Wu Bo, Ruan Chengjiang, Han Ping, Ruan Dong, Xiong ChaoWei, Ding Jian, Liu Sihei
1Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education, Institute of Plant Resources, Dalian Minzu University, No. 18 Liaohe West Road, Dalian, 116600 Liaoning China.
Tongren Engineering Research Center for Oiltea Camellia, Yuping, 554000 China.
3 Biotech. 2019 Jul;9(7):257. doi: 10.1007/s13205-019-1792-7. Epub 2019 Jun 8.
Tea oil camellia () is an important woody oil tree in southern China. However, little is known regarding the molecular mechanisms that contribute to high oleic acid accumulation in tea oil camellia. Herein, we measured the oil content and fatty acid compositions of high- and low-oil tea oil camellia seeds and investigated the global gene expression profiles by RNA-seq. The results showed that at the early, second and third seed developmental stages, a total of 64, 253, and 124 genes, respectively, were significantly differentially expressed between the high- and low-oil cultivars. Gene ontology (GO) enrichment analysis of the identified differentially expressed transcription factors (TFs; ABI3, FUS3, LEC1, WRI1, TTG2 and DOF4.6) revealed some critical GO terms associated with oil biosynthesis and fatty acid accumulation, including glycolysis, zinc ion binding, positive regulation of fatty acid biosynthetic process, triglyceride biosynthetic process, seed coat development, abscisic acid-mediated signaling pathway and embryo development. Comprehensive comparisons of transcriptomic profiles and expression analysis of multigenes based on qRT-PCR showed that coordinated high expression of the upstream genes , and directly increased the relative levels of C16:0-ACP, which provided enough precursor resources for oleic acid biosynthesis. Continuous high expression of the gene accelerated oleic acid synthesis and accumulation, and coordinated low expression of the downstream genes and decreased the consumption of oleic acid for conversion. The coordinated regulation of these multigenes ensures the high accumulation of oleic acid in the seeds of tea oil camellia. Our data represent a comprehensive transcriptomic study of high- and low-oil tea oil camellia, not only increasing the number of sequences associated with lipid biosynthesis and fatty acid accumulation in public resource databases but also providing a scientific basis for genetic improvement of the oleic acid content in woody oil trees.
油茶（）是中国南方重要的木本油料树种。然而，关于油茶中高油酸积累的分子机制知之甚少。在此，我们测定了高油和低油油茶种子的油含量和脂肪酸组成，并通过RNA测序研究了整体基因表达谱。结果表明，在种子发育的早期、中期和后期，高油和低油品种之间分别共有64、253和124个基因显著差异表达。对鉴定出的差异表达转录因子（ABI3、FUS3、LEC1、WRI1、TTG2和DOF4.6）进行基因本体（GO）富集分析，揭示了一些与油脂生物合成和脂肪酸积累相关的关键GO术语，包括糖酵解、锌离子结合、脂肪酸生物合成过程的正调控、甘油三酯生物合成过程、种皮发育、脱落酸介导的信号通路和胚胎发育。转录组图谱的综合比较以及基于qRT-PCR的多基因表达分析表明，上游基因、和的协同高表达直接增加了C16:0-ACP的相对水平，为油酸生物合成提供了足够的前体资源。基因的持续高表达加速了油酸的合成和积累，下游基因和的协同低表达减少了油酸转化的消耗。这些多基因的协同调控确保了油茶种子中油酸的高积累。我们的数据代表了对高油和低油油茶的全面转录组研究，不仅增加了公共资源数据库中与脂质生物合成和脂肪酸积累相关的序列数量，还为木本油料树种油酸含量的遗传改良提供了科学依据。
