Yang Weizong, Xin Ziwei, Xie Lihang, Zhai Yuhui, Zhang Yanlong, Niu Lixin, Zhang Qingyu
College of Landscape Architecture and Arts, Northwest A&F University, Yangling 712100, Shaanxi, China.
Academy of Medical Sciences, Zhengzhou University, Zhengzhou 450000, China.
Hortic Res. 2023 May 15;10(7):uhad106. doi: 10.1093/hr/uhad106. eCollection 2023 Jul.
Tree peony () is an excellent woody oilseed crop, known for its high α-linolenic acid (ALA, ~45%) content, which is of great value for human health. However, the mechanisms underlying this high-level ALA accumulation in tree peony seeds are poorly understood. In this study, we evaluated the dynamic changes in the lipidomic profile of seeds during development. A total of 760 lipid molecules were identified in seeds; triacylglycerol (TAG) lipid molecules showed the highest abundance and diversity, both increasing during seed development. Particularly, ALA was the predominant fatty acid at the TAG -3 position. We further characterized two diacylglycerol acyltransferase (DGAT) genes and three phospholipid:diacylglycerol acyltransferase (PDAT) genes involved in the transfer of fatty acids to the TAG -3 position. Gene expression and subcellular localization analyses suggested that PrDGATs and PrPDATs may function as endoplasmic reticulum-localized proteins in seed TAG biosynthesis. functional complementation analysis showed different substrate specificities, with PrPDAT2 having a specific preference for ALA. Multiple biological assays demonstrated that PrDGAT1, PrDGAT2, PrPDAT1-2, and PrPDAT2 promote oil synthesis. Specifically, PrPDAT2 leads to preferential ALA in the oil. Our findings provide novel functional evidence of the roles of and , which are potential targets for increasing the ALA yield in tree peony and other oilseed crops.
牡丹是一种优良的木本油料作物，以其高含量的α-亚麻酸（ALA，约45%）而闻名，这对人体健康具有重要价值。然而，牡丹种子中这种高水平ALA积累的潜在机制尚不清楚。在本研究中，我们评估了牡丹种子发育过程中脂质组图谱的动态变化。在牡丹种子中总共鉴定出760种脂质分子；三酰甘油（TAG）脂质分子的丰度和多样性最高，在种子发育过程中均增加。特别是，ALA是TAG -3位的主要脂肪酸。我们进一步鉴定了两个参与脂肪酸向TAG -3位转移的二酰甘油酰基转移酶（DGAT）基因和三个磷脂：二酰甘油酰基转移酶（PDAT）基因。基因表达和亚细胞定位分析表明，PrDGATs和PrPDATs可能作为内质网定位蛋白在种子TAG生物合成中发挥作用。功能互补分析显示出不同的底物特异性，其中PrPDAT2对ALA有特定偏好。多种生物学试验表明，PrDGAT1、PrDGAT2、PrPDAT1-2和PrPDAT2促进油脂合成。具体而言，PrPDAT2导致油脂中优先积累ALA。我们的研究结果为PrDGATs和PrPDATs的作用提供了新的功能证据，它们是提高牡丹和其他油料作物中ALA产量的潜在靶点。
