State Key Laboratory of Natural Medicines and Jiangsu Key of Bioactive Natural Product Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 210009, People's Republic of China.
State Key Laboratory of Natural Medicines and Jiangsu Key of Bioactive Natural Product Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 210009, People's Republic of China.
Food Res Int. 2021 Nov;149:110678. doi: 10.1016/j.foodres.2021.110678. Epub 2021 Aug 31.
Sunflower pollen is a natural nutritious food with a long history and multiple functions, however, the main chemical components apart from flavonoids and their biosynthesis processes have not been thoroughly investigated. In this study, seven hydroxycinnamic acid amides (HCAAs) (1-7) abundant in sunflower pollen were isolated and identified as one type of the pollen's main chemicals. For a comprehensive understanding of HCAA biosynthesis in Helianthus annuus flowers, RNA-seq, metabolomics, and key genes related to biosynthesis in the sunflower were studied. A large number of compounds at different sunflower growth stages (the 7th, 14th, 21st, and 28th days) and high expression levels of related genes in the transcriptome were detected. A molecular network was constructed to clarify the synthetic pathway of HCAAs, which revealed high transcriptional levels of spermidine hydroxycinnamoyl transferase genes (HaSHT2795 and HaSHT2436) in 14-21-days-old flowers. HaSHT2795 enzymes catalyze tri-coumaroylspermidine formation, and virus-induced gene silencing to inhibit HaSHT2795 and HaSHT2436 could significantly reduce the synthesis of hydroxycinnamic acid amides in sunflower pollen. HCAAs were inferred to be related to the formation of pollen walls and the health effects of pollen. Analyzing HCAA biosynthesis and accumulation in H. annuus pollen will be helpful to understand the functions of HCAAs in the development of pollen and its nutritional value.
葵花花粉是一种天然的营养食品，具有悠久的历史和多种功能，然而，除了类黄酮之外，其主要化学成分及其生物合成过程尚未得到彻底研究。在这项研究中，从葵花花粉中分离并鉴定出七种丰富的羟基肉桂酰胺（HCAAs）（1-7），它们是花粉的主要化学成分之一。为了全面了解向日葵花中 HCAA 的生物合成，研究了 RNA-seq、代谢组学以及与向日葵生物合成相关的关键基因。在不同向日葵生长阶段（第 7、14、21 和 28 天）检测到大量化合物和转录组中相关基因的高表达水平。构建了一个分子网络来阐明 HCAAs 的合成途径，该途径揭示了在 14-21 天龄的花朵中，多聚精胺羟基肉桂酰基转移酶基因（HaSHT2795 和 HaSHT2436）的转录水平较高。HaSHT2795 酶催化三香豆酰基多聚精胺的形成，病毒诱导的基因沉默抑制 HaSHT2795 和 HaSHT2436 可以显著降低向日葵花粉中羟基肉桂酰胺的合成。推测 HCAAs 与花粉壁的形成和花粉的健康效应有关。分析向日葵花粉中 HCAA 的生物合成和积累有助于了解 HCAAs 在花粉发育及其营养价值中的功能。
