Li Zhiyuan, Jiang Hong, Yan Huizhuan, Jiang Xiumei, Ma Yan, Qin Yong
College of Forestry and Horticulture, Xinjiang Agriculture University, Urumuqi, China.
Institute of Agricultural Mechanization, Xinjiang Academy of Agricultural Sciences, Urumuqi, China.
PeerJ. 2021 Sep 10;9:e12152. doi: 10.7717/peerj.12152. eCollection 2021.
Flavonoids are phytochemicals present in medicinal plants and contribute to human health. , a species rich in flavonoids, has long been used in traditional medicine and as a food resource. N (nitrogen) fertilization can reduce flavonoid accumulation in . However, there is limited knowledge regarding N regulatory mechanisms. The aim of this study was to determine the effect of N availability on flavonoid biosynthesis in and to investigate the relationship between C (carbon) and N metabolism coupled with flavonoid synthesis under controlled conditions. seedlings were grown hydroponically under five different N levels (0, 0.625, 1.250, 2.500 and 5.000 mM). The related indexes of C, N and flavonoid metabolism of under N variation were measured and analysed. N availability (low and moderate N levels) regulates enzyme activities related to C and N metabolism, promotes the accumulation of carbohydrates, reduces N metabolite levels, and enhances the internal C/N balance. The flavonoid content in roots and stalks remained relatively stable, while that in leaves peaked at low or intermediate N levels. Flavonoids are closely related to phenylalanine ammonia-lyase (PAL), cinnamate 4-hydroxylase (C4H), 4-coumarate: coenzyme A ligase (4CL), and chalcone-thioase (CHS) activity, significantly positively correlated with carbohydrates and negatively correlated with N metabolites. Thus, C and N metabolism can not only control the distribution of C in amino acid and carbohydrate biosynthesis pathways but also change the distribution in flavonoid biosynthesis pathways, which also provides meaningful information for maintaining high yields while ensuring the nutritional value of crop plants.
黄酮类化合物是存在于药用植物中的植物化学物质，对人体健康有益。[植物名称]是一种富含黄酮类化合物的植物，长期以来一直被用于传统医学和作为食物来源。氮肥施用会减少[植物名称]中黄酮类化合物的积累。然而，关于氮调节机制的知识有限。本研究的目的是确定氮有效性对[植物名称]中黄酮类化合物生物合成的影响，并在可控条件下研究碳（C）和氮代谢与黄酮类化合物合成之间的关系。[植物名称]幼苗在五种不同氮水平（0、0.625、1.250、2.500和5.000 mM）下进行水培生长。测定并分析了氮变化条件下[植物名称]碳、氮和黄酮类化合物代谢的相关指标。氮有效性（低氮和中氮水平）调节与碳和氮代谢相关的酶活性，促进碳水化合物积累，降低氮代谢物水平，并增强内部碳/氮平衡。根和茎中的黄酮类化合物含量保持相对稳定，而叶中的黄酮类化合物含量在低氮或中氮水平时达到峰值。黄酮类化合物与苯丙氨酸解氨酶（PAL）、肉桂酸4-羟化酶（C4H）、4-香豆酸：辅酶A连接酶（4CL）和查尔酮硫解酶（CHS）活性密切相关，与碳水化合物显著正相关，与氮代谢物负相关。因此，碳和氮代谢不仅可以控制碳在氨基酸和碳水化合物生物合成途径中的分配，还可以改变黄酮类化合物生物合成途径中的分配，这也为在确保作物营养价值的同时维持高产提供了有意义的信息。
