Department of life science, Lyuliang University, Lvliang, 033000, China.
College of Horticulture, Shanxi Agricultural University, Taigu, 030801, China.
BMC Plant Biol. 2023 Jan 23;23(1):50. doi: 10.1186/s12870-022-04020-x.
Hemerocallis citrina Baroni (daylily) is a horticultural ornamental plant and vegetable with various applications as a raw material in traditional Chinese medicine and as a flavouring agent. Daylily contains many functional substances and is rich in lecithin, which is mostly composed of glycerophospholipids. To study the comprehensive dynamic changes in glycerophospholipid during daylily flowering and the underlying signalling mechanisms, we performed comprehensive, time-resolved lipidomic and transcriptomic analyses of 'Datong Huanghua 6' daylily.
Labelling with PKH67 fluorescent antibodies clearly and effectively helped visualise lipid changes in daylily, while relative conductivity and malonaldehyde content detection revealed that the early stages of flowering were controllable processes; however, differences became non-significant after 18 h, indicating cellular damage. In addition, phospholipase D (PLD) and lipoxygenase (LOX) activities increased throughout the flowering process, suggesting that lipid hydrolysis and oxidation had intensified. Lipidomics identified 558 lipids that changed during flowering, with the most different lipids found 12 h before and 12 h after flowering. Transcriptome analysis identified 13 key functional genes and enzymes in the glycerophospholipid metabolic pathway. The two-way orthogonal partial least squares analysis showed that diacylglycerol diphosphate phosphatase correlated strongly and positively with phosphatidic acid (PA)(22:0/18:2), PA(34:2), PA(34:4), and diacylglycerol(18:2/21:0) but negatively with phospholipase C. In addition, ethanolamine phosphotransferase gene and phospholipid-N-methyltransferase gene correlated positively with phosphatidylethanolamine (PE)(16:0/18:2), PE(16:0/18:3), PE(33:2), and lysophosphatidylcholine (16:0) but negatively with PE(34:1).
Overall, this study elucidated changes in the glycerophospholipid metabolism pathway during the daylily flowering process, as well as characteristic genes, thus providing a basis for future studies of glycerophospholipids and signal transduction in daylilies.
黄花菜（Hemerocallis citrina Baroni）是一种园艺观赏植物和蔬菜，具有多种应用，可作为中药材的原料和调味剂。黄花菜含有许多功能性物质，富含卵磷脂，主要由甘油磷脂组成。为了研究黄花菜开花过程中甘油磷脂的综合动态变化及其潜在的信号机制，我们对‘大同黄花 6 号’黄花菜进行了全面、时间分辨的脂质组学和转录组学分析。
PKH67 荧光抗体标记清楚有效地帮助可视化了黄花菜中的脂质变化，而相对电导率和丙二醛含量检测表明，开花的早期阶段是可控过程；然而，在 18 小时后差异变得不显著，表明细胞受损。此外，磷脂酶 D（PLD）和脂氧合酶（LOX）活性在整个开花过程中增加，表明脂质水解和氧化加剧。脂质组学鉴定出 558 种在开花过程中发生变化的脂质，其中在开花前 12 小时和开花后 12 小时差异最大。转录组分析鉴定出甘油磷脂代谢途径中的 13 个关键功能基因和酶。双向正交偏最小二乘法分析表明，二酰甘油二磷酸磷酸酶与磷脂酸（PA）（22：0/18：2）、PA（34：2）、PA（34：4）和二酰甘油（18：2/21：0）呈强正相关，但与磷脂酶 C 呈负相关。此外，乙醇胺磷酸转移酶基因和磷脂-N-甲基转移酶基因与磷脂酰乙醇胺（PE）（16：0/18：2）、PE（16：0/18：3）、PE（33：2）和溶血磷脂酰胆碱（16：0）呈正相关，但与 PE（34：1）呈负相关。
总的来说，本研究阐明了黄花菜开花过程中甘油磷脂代谢途径的变化以及特征基因，为今后黄花菜甘油磷脂和信号转导的研究提供了基础。
