Plant Cell Biotechnology Department, CSIR-Central Food Technological Research Institute (CSIR-CFTRI), Mysuru, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India; Kansas Lipidomics Research Center, Division of Biology, Kansas State University, Manhattan, KS 66506, USA.
Plant Cell Biotechnology Department, CSIR-Central Food Technological Research Institute (CSIR-CFTRI), Mysuru, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India.
Plant Sci. 2022 Nov;324:111445. doi: 10.1016/j.plantsci.2022.111445. Epub 2022 Aug 28.
Buglossoides arvensis is a burgeoning oilseed crop that contains an unique combination of ω-3 and ω-6 polyunsaturated fatty acids (PUFA), constituting ~80-85% of seed triacylglycerols (TAGs). To uncover the critical TAG biosynthetic pathways contributing for high PUFA accumulation, we performed lipidome of developing seeds and characterized acyltransferases involved in the final step of TAG biosynthesis. During seed development, distribution of lipid molecular species in individual lipid classes showed distinct patterns from an early-stage (6 days after flowering (DAF)) to the middle-stage (12 and 18 DAF) of oil biosynthesis. PUFA-containing TAG species drastically increased from 6 to 12 DAF. The expression profiles of key triacylglycerol biosynthesis genes and patterns of phosphatidylcholine, diacylglycerol and triacylglycerol molecular species during seed development were used to predict the contribution of diacylglycerol acyltransferases (DGAT1 and DGAT2) and phospholipid: diacylglycerol acyltransferases (PDAT1 and PDAT2) to PUFA-rich TAG biosynthesis. Our analysis suggests that DGATs play a crucial role in enriching TAGs with PUFA compared to PDATs. This was further confirmed by fatty acid feeding studies in yeast expressing acyltransferases. BaDGAT2 preferentially incorporated high amounts of PUFAs into TAG, compared to BaDGAT1. Our results provide insight into the molecular mechanisms of TAG accumulation in this plant and identify target genes for transgenic production of SDA in traditional oilseed crops.
苍耳为一种新兴的油料作物，其种子中含有独特比例的 ω-3 和 ω-6 多不饱和脂肪酸（PUFA），占种子三酰基甘油（TAG）的 80-85%。为了揭示对高 PUFA 积累有贡献的关键 TAG 生物合成途径，我们对发育中的种子进行了脂质组学分析，并对参与 TAG 生物合成最后一步的酰基转移酶进行了特征分析。在种子发育过程中，各个脂质类别中单分子脂质种类的分布模式从早期（开花后 6 天（DAF））到油脂生物合成的中期（12 和 18 DAF）发生了明显变化。含 PUFA 的 TAG 种类从 6 天到 12 天急剧增加。在种子发育过程中，关键三酰基甘油生物合成基因的表达谱和磷脂酰胆碱、二酰基甘油和三酰基甘油分子种类的模式被用来预测二酰基甘油酰基转移酶（DGAT1 和 DGAT2）和磷脂：二酰基甘油酰基转移酶（PDAT1 和 PDAT2）对富含 PUFA 的 TAG 生物合成的贡献。我们的分析表明，与 PDAT 相比，DGAT 在将 PUFA 富集到 TAG 中起着至关重要的作用。这一点通过在表达酰基转移酶的酵母中进行脂肪酸喂养研究得到了进一步证实。与 BaDGAT1 相比，BaDGAT2 更倾向于将大量的 PUFAs 掺入 TAG 中。我们的研究结果为该植物 TAG 积累的分子机制提供了深入的了解，并为传统油料作物中 SDA 的转基因生产确定了目标基因。
