Yuan Lixia, Mao Xue, Zhao Kui, Ji Xiajie, Ji Chunli, Xue Jinai, Li Runzhi
Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu 030801, Shanxi, China.
College of Biological Science and Technology, Jinzhong University, Jinzhong 030600, Shanxi, China.
Biol Open. 2017 Jul 15;6(7):1024-1034. doi: 10.1242/bio.026534.
As an important oilseed worldwide, is being increasingly explored for its use in production of food, feed, biofuel and industrial chemicals. However, detailed mechanisms of camelina oil biosynthesis and accumulation, particularly in vegetative tissues, are understood to a very small extent. Here, we present genome-wide identification, cloning and functional analysis of phospholipid diacylglycerol acyltransferase (PDAT) in , which catalyses the final acylation step in triacylglycerol (TAG) biosynthesis by transferring a fatty acyl moiety from a phospholipid to diacylglycerol (DAG). We identified five genes (namely , , and and and ) encoding PDATs from the camelina genome. is mainly expressed in seeds, whereas preferentially accumulates in flower and leaf tissues. High expression of and was detected in stem and root tissues, respectively. Cold stress induced upregulation of and expression by 3.5- and 2.5-fold, respectively, compared to the control. Salt stress led to an increase in transcripts by 5.1-fold. Drought treatment resulted in an enhancement of mRNAs by twofold and a reduction of expression. Osmotic stress upregulated the expression of by 3.3-fold. Furthermore, the cDNA clones of these genes were isolated for transient expression in tobacco leaves. All five genes showed PDAT enzymatic activity and substantially increased TAG accumulation in the leaves, with CsPDAT1-A showing a higher preference for ɑ-linolenic acid (18:3 ω-3). Overall, this study demonstrated that different members of CsPDAT family contribute to TAG synthesis in different tissues. More importantly, they are involved in different types of stress responses in camelina seedlings, providing new evidence of their roles in oil biosynthesis and regulation in camelina vegetative tissue. The identified CsPDATs may have practical applications in increasing oil accumulation and enhancing stress tolerance in other plants as well.
作为全球一种重要的油料作物，人们对其在食品、饲料、生物燃料和工业化学品生产中的应用探索日益深入。然而，对于亚麻荠油脂生物合成和积累的详细机制，尤其是在营养组织中的机制，目前了解甚少。在此，我们对亚麻荠中的磷脂二酰甘油酰基转移酶（PDAT）进行了全基因组鉴定、克隆及功能分析，该酶通过将磷脂上的脂肪酰基部分转移至二酰甘油（DAG）来催化三酰甘油（TAG）生物合成的最后酰化步骤。我们从亚麻荠基因组中鉴定出五个编码PDAT的基因（即 、 、 、 和 ）。 主要在种子中表达，而 在花和叶组织中优先积累。在茎和根组织中分别检测到 和 的高表达。与对照相比，冷胁迫分别使 和 的表达上调3.5倍和2.5倍。盐胁迫导致 的转录本增加5.1倍。干旱处理使 的mRNA增加两倍，并使 的表达降低。渗透胁迫使 的表达上调3.3倍。此外，分离出这些 基因的cDNA克隆用于在烟草叶片中瞬时表达。所有五个基因均显示出PDAT酶活性，并显著增加了叶片中的TAG积累，其中CsPDAT1 - A对α - 亚麻酸（18:3 ω - 3）表现出更高的偏好性。总体而言，本研究表明CsPDAT家族的不同成员在不同组织中对TAG合成有贡献。更重要的是，它们参与了亚麻荠幼苗对不同类型胁迫的响应，为其在亚麻荠营养组织中油脂生物合成和调控中的作用提供了新证据。所鉴定出的CsPDATs在增加其他植物油脂积累和增强胁迫耐受性方面也可能具有实际应用价值。
