Carbon and nitrogen metabolism under nitrogen variation affects flavonoid accumulation in the leaves of Coreopsis tinctoria

Abstract

Flavonoids are phytochemicals present in medicinal plants and contribute to human health. Coreopsis tinctoria, 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 C. tinctoria. 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 C. tinctoria and to investigate the relationship between C (carbon) and N metabolism coupled with flavonoid synthesis under controlled conditions. C. tinctoria 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 C. tinctoria 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.

Effects of Shading Nets on Reactive Oxygen Species Accumulation, Photosynthetic Changes, and Associated Physiochemical Attributes in Promoting Cold-Induced Damage in Camellia sinensis (L.) Kuntze

“…In the development of tea plants, different shade treatments had a substantial impact on chlorophyll and biochemical components, as well as carbon and nitrogen regulation [24,35,43]. Photosynthesis and photosynthetic pigments can deliver energy for specialized metabolism of plants and carbon and nitrogen are both crucial for synthesis of photosynthetic products, enzymes, and chloroplasts in plants [33]. We also observed that both carbon and nitrogen contents are stable under different shading conditions in tea plants.…”

“…For determination of carbon and nitrogen, the dried samples at 70 • C were grounded into powder and then cooled at 25 • C. A total of 1 mg of tea leaves was analyzed using an elemental analyzer (EA3000, Euro Vector, Italy) to determine the total C and N contents according to [33].…”

Biogenic Phytochemicals Modulating Obesity: From Molecular Mechanism to Preventive and Therapeutic Approaches

“…These products contain dietary phytochemicals with a high potential for health promotion and disease prevention [ 17 , 18 ]. Multiple phytochemicals combinations may result in synergistic activity that increases their bioavailability and their action on multiple molecular targets, thus offering advantages over treatments with single chemicals [ 15 , 19 ]. The antiobesity effects of these compounds are mediated by the regulation of various pathways, including lipid absorption, intake, and expenditure of energy, increasing lipolysis, and decrease lipogenesis, and differentiation and proliferation of preadipocytes as shown in Figure 1 [ 15 ].…”

Potassium (K+) Starvation-Induced Oxidative Stress Triggers a General Boost of Antioxidant and NADPH-Generating Systems in the Halophyte Cakile maritima

“…In addition to the ferredoxin-NADP reductase (FNR) in photosynthetic cells, NADPH is mainly generated by NADP-isocitrate dehydrogenase (NADP-ICDH), NADP-malic enzyme (NADP-ME) also named NADP-malate dehydrogenase, glucose-6-phosphate dehydrogenase (G6PDH), and 6-phosphogluconate dehydrogenase (6PGDH), the latter two belonging to the oxidative part of the pentose phosphate pathway. All these enzymes are also involved in diverse, basic metabolic pathways such as carbon and nitrogen metabolisms [ 23 , 24 , 25 , 26 , 27 ].…”