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Paeonia ostii is recognized as an important oilseed tree peony species with potential as a raw material source for cosmetic and health care products, strong seed setting capacity, high seed oil yield, and abundant omega-3 polyunsaturated fatty acids. P. ostii, commonly called Fengdan, is widely cultivated in China. The cultivation method difference has an important influence on the oil-use feature, which is a key index for evaluating the quality of oilseed crops. This study aimed to select an optimal cultivation method to provide the first reference data for high-yield and high-quality seed oil harvesting and to facilitate the understanding of the quality difference in the formation mechanism of seed oil in cultivated P. ostii. This study selected five representative cultivation methods, open field cultivation, sunny slope cultivation, shady slope cultivation, understory intercropping cultivation, and high-altitude cultivation, and investigated the influence of cultivation method differences on the oil-use feature based on the three aspects of seed yield traits, oil yield, and fatty acid compositions. Six seed yield traits (fruit pod length, fruit pod width, fruit pod thickness, number of fruit pods per plant, 1000-grain weight, and seed yield per plant) and oil yield reached the maximum values of 7.75 cm, 6.99 cm, 1.57 cm, 11.33, 290.45 g, 85.8 g, and 30.41%, respectively, using the understory intercropping cultivation method. Fatty acid compositions were mainly identified as α-linolenic acid, linoleic acid, oleic acid, stearic acid, and palmitic acid, with significant content differences among different cultivation methods (P < 0.05). Functional component α-linolenic acid and total amounts of unsaturated fatty acids reached the maximum values of 46.85% and 65.23%, respectively, with high-altitude cultivation and understory intercropping cultivation. The seed yield traits, oil yield, and total amounts of unsaturated fatty acids were optimal with the understory intercropping cultivation method, whereas high-altitude cultivation was conducive to the accumulation of α-linolenic acid. Understory intercropping cultivation with appropriate altitude increases is recommended as a preponderant cultivation method for high-yield and high-quality seed oil harvesting for this crop.

Graphene oxide (GO) is considered to be an emerging environmental pollutant with its inevitable release into the environment. Thus, its potential environmental risks and biosafety are receiving increased attention. In this study, Paeonia ostii was exposed to GO under drought stress. The results demonstrated that GO prevented soil water from evaporating due to its hydrophilic oxygen-containing functional groups and did not change the soil pH. Moreover, GO treatment resulted in lower increases in reactive oxygen species, relative electrical conductivity and free proline content, and greater increases in the antioxidant enzyme activities of P. ostii under drought stress compared with those in the control. And under drought stress, higher photosynthesis, more intact mesophyll cells and organelles and open stomata were found in P. ostii under GO treatment. Furthermore, GO treatment induced greater changes in the expression patterns of genes required for lignin biosynthesis, photosynthesis-antenna proteins, carbon fixation in photosynthetic organisms, and glyoxylate and dicarboxylate metabolism. Additionally, GO did not accumulate in P. ostii due to the soil environment and the electrostatic repulsion between GO and the roots. GO did not have toxic effects on P. ostii and was an effective soil water retention agent; therefore, it could be economically beneficial for the production of plants under drought stress.

Paeonia ostii T. Hong & J.X. Zhang, an emerging oil crop, was intercropped with 3-year-old plantations of pawpaw [Chaenomeles sinensis (Thouin.) Koehne], Chinese toon (Toona sinensis Roem.), and walnut (Juglans regia L.). In order to achieve a better production system, we studied the effects of intercropping on the photosynthesis, growth, and yield of P. ostii. The results showed that different pattern of agroforestry systems changed microclimatic and growing site conditions in comparison to the control treatment. The correlation analysis demonstrated that both similarities and differences were found in relationship between net photosynthetic rate (PN) and main ecophysiological factors at different treatments. Agroforestry systems significantly reduced transpiration rate and increased water-use efficiency (WUE), maximal quantum yield of PSII photochemistry, chlorophyll (Chl) a and total Chl contents, whereas there were no differences between PN, intercellular CO2 concentration, photochemical efficiency of PSII in the light, and plant height in these systems. The obviously exponential relationship between PN and PAR during a day were observed in Chinese toon and walnut treatments. The highest effective quantum yield of PSII photochemistry, electron transport rate, and photochemical quenching coefficient were observed in walnut treatment. The higher WUE and SPAD value, the thinnest stem, the biggest crown, the lowest stomatal conductance, and Chl a/b ratio as well as the fewest pods and harvest seed yield were observed in pawpaw treatment. In addition, there was a significant correlation between SPAD value and Chl (a+b) of P. ostii in agroforestry system. This study could be an important contribution for the science of land management in oil peony and other understory crops.

Multi-walled carbon nanotubes (MWCNTs) are considered important nanomaterials with rapidly growing applications. They are inevitably released into the environment, which has attracted considerable attention for their potential threats to ecosystems. In this study, Paeonia ostii T. Hong et J. X. Zhang was exposed to MWCNTs at different concentrations under high temperature. The results showed that high temperature-induced P. ostii damage was prevented by MWCNTs, and 200 mg/L was the most effective concentration. First, MWCNTs prevented increases in reactive oxygen species, relative electrical conductivity and free proline content, and reduced decreases in SPAD, chlorophyll and carotenoid contents. Moreover, the ascorbate-glutathione (ASA-GSH) cycle was activated in response to the MWCNTs treatments, whereas the superoxide dismutase and catalase activities were inhibited. And the MWCNTs treatments also resulted in higher photosynthesis and more intact anatomical structures. Furthermore, the metabolome also confirmed that the ASA-GSH cycle played a critical role in P. ostii high-temperature tolerance, and other biological processes also responded to the MWCNTs treatments. Additionally, the genes involved in the P. ostii ASA-GSH cycle were highly expressed in response to the MWCNTs treatments. These results elucidated the beneficial role of MWCNTs in P. ostii growth under high temperature.

As emerging woody oil crops, the tree peony seeds recently have been attracting great attention for their metabolites and bioactivities. In this research, the phytochemical profiles of the seed coats of tree peonies from different production regions were investigated systematically. Twelve phytochemicals were separated and prepared, mainly belonging to stilbenes. A great variation in stilbene content was detected in the three Paeonia plants, and Paeonia ostii seed coats (POSC) had significantly higher contents of the stilbene compounds than other species. There were nineteen significant correlations between ecogeographical factors and the predominant compounds. A clear discrimination among the species was observed in their HPLC fingerprint and chemometric analysis. Furthermore, POSC extracts could significantly reduce the starch mediated PBG (postprandial blood glucose) levels in normal/diabetic mice. Meanwhile, in vitro enzyme tests revealed that the predominant compounds, suffruticosol B and ampelopsin D, could effectively and competitively inhibit α-glucosidase, indicating that POSC could be a natural source of hypoglycemics in the food and drug fields.

Background Selenium is an essential micronutrient in human metabolism. However, the Se level in foods is far below the standards due to the fact that it is deficient in two thirds of arable soils. Therefore, consuming Se-enriched plant products which convert inorganic Se into organic Se might be a safe and effective way to supplement Se for the human body. Paeonia ostii is a unique medicinal and edible plant in China, and also a new special woody oil crop. It serves as a perfect mediator for Se biofortification. In this report the effects of nano-Se foliar application on photosynthetic parameters, physiological characteristics and Se-enrichment effect in various plant organs of P. ostii cultivar Feng Dan were investigated in randomized complete block design experiments with different doses of spray in Se-deficient soils.Results By contrast to the control, nano-Se sprays enhanced net photosynthetic rate, transpiration rate, stomatal conductance, intercellular CO2 concentration, and chlorophyll content of Feng Dan. The content of soluble sugar, soluble protein, proline and activities of superoxide dismutase and peroxidase were increased while malondialdehyde content was significantly reduced. The stimulatory effect at concentrations of 6.00 and 8.25 g·hm-2 was the best in this study. nano-Se application significantly increased the Se content in all organs of Fengdan except the root compared to the control, and Se contents in various organs were increased paralleled with the increase of concentrations applied, and ordered as follows under suitable concentration, Testa > leaf > kernel > stem > root.ConclusionsThe above results show that nano-Se sprays at concentrations of 6.00-8.25 g·hm-2 stimulated the growth of Feng Dan and achieved the best Se-enrichment effect in this study. It also proved that the Se biofortification effect depends on its dosage applied and types of plant organs. These results provide guidance on Se enrichment of horticultural crops.

Paeonia ostii ‘Feng dan’ is recommended as a new promising oil crop because of the nutrient elements in its seed; however, the development of this new oil crop is now limited due to its low seed setting rate. This study identified ways to improve the cross pollination of Feng dan as the maternal parent, which has been proved to be a suitable oil crop, so as to improve the seed setting rate of ‘Feng dan’, and to predict the functional relationship between pollen vigor and seed setting rate. improving the efficiency of cross pollination. Three major steps were conducted, first, to screen the appropriate method of measuring pollen vigor of the paternal parent, which could have a strong relationship with seed setting rate. Second, to obtain the corresponding seed setting rate by cross pollination. Third, the functional relationship between two indexes was founded which could be used in cross pollination practice. Results indicated that the best paternal parents of ‘Feng dan’ were ‘Feng dan’ cultivars from other different cultivation populations; The most suitable medium concentration for pollen germination was 100~150 g/L sucrose, 0.06~0.08 g/L boric acid, and 50~200 g/L PEG-6000. Both the seed setting rate and the number of seed grains were positively correlated with the pollen activity, and the seed setting rate was negatively correlated with the local precipitation.

Paeoniaceae is an abundant germplasm resource with significant medicinal values in China, the principal medicinal components of which include paeoniflorin and paeonol. These compounds are typically obtained from air-dried root samples, which the use of freeze-drying as an alternative method has not been tested. Additionally, the presence of these two compounds in various wild Paeoniaceae species has not been previously explored, nor have the differences between various plant organs been fully evaluated. Here, freeze-drying and air-drying methods were compared to assess the changes in paeoniflorin and paeonol in root samples using ultra-performance liquid chromatography-mass spectrometer. The contents of these compounds in the roots, leaves, stems, and petals were then tested in freeze-dried materials. We also quantitatively detected the paeoniflorin and paeonol contents in the roots of 14 species collected from 20 natural habitats. Results indicated that the paeoniflorin content decreased under air-drying in comparison to freeze-drying, while the opposite trend was observed for paeonol. Our findings also demonstrated that the root xylem of species in Section Moutan, particularly Paeonia ostii, contains considerable paeonol and paeoniflorin and should thus be fully utilized as a medicinal resource. Furthermore, paeonol was mainly detected in the roots, while paeoniflorin was widely distributed in different organs; the highest content was in the leaf at the budding stage, suggesting that the leaves should be developed as a new paeoniflorin resource. Paeoniflorin contents were also found to be higher at earlier development stages. Based on the standards of the Chinese Pharmacopoeia, five species of Section Moutan and six species of Section Paeonia could be used as potential traditional Chinese medicinal resources. These findings of this study enhance our understanding of these two medicinal compounds and provide a foundation for the further development and utilization of Paeoniaceae as medicinal plant resources.

The cortex root of Paeonia ostii, is used as a traditional Chinese medicine for treating female diseases. Phytochemical investigation of the water-soluble fraction of the plant led to the isolation of two new acetoisovanillone glycosides: acetoisovanillone-3-O-β-D-glucopyranoside (1) and 2-hydroxy-acetoisovanillone-3-O-β-D-glucopyranoside (2). Their structures were elucidated by extensive spectroscopic methods.

Tree peony (Paeonia section Moutan DC.) is an excellent ornamental plant, of which Paeonia ostii (P. ostii) has a high oil value. It is widely cultivated in China, but severe drought affects its growth. In this study, the effects of exogenous calcium on drought-induced damage of P. ostii were studied. The results showed that under drought stress, leaf water content showed a downward trend, while reactive oxygen species (ROS), relative electrical conductivity (REC), proline (Pro) content, and related antioxidant enzymes increased significantly. Spraying CaCl2 could effectively slow leaf wilting and water loss, induced an increase in enzyme activity of the antioxidant enzyme system, and reduced the accumulation of ROS caused by drought stress. Simultaneously, REC and Pro content could be alleviated, and the degree of cell membrane damage could be reduced. In addition, CaCl2 improved photosynthetic characteristics and chlorophyll fluorescence parameters. These results indicated that CaCl2 reduced the harmful effects of drought stress on the growth of P. ostii by regulating infiltration, activating photosynthesis, and enhancing the antioxidant system. These findings suggested that CaCl2 can be used to manage drought stress in P. ostii cultivation.

Two tree peony species, Paeonia ostii and Paeonia rockii, from eight different provenances in China (four provenances for each species) were collected for their photosynthetic characteristics. Their diurnal variations of photosynthesis, the light- and CO2-response curves and chlorophyll content were determined. Among all eight provenances, Ziwuling P. rockii had a significantly higher average daily net photosynthetic rate, showing a superior photosynthetic capacity, followed by Fengxiang P. ostii and Xunyang P. ostii. In addition, Ziwuling P. rockii had the highest maximum net photosynthetic rates, thus, presented a strong photosynthetic potential. Furthermore, Xunyang P. ostii, Fengxiang P. ostii, and Heze P. ostii also exhibited a great photosynthetic capacity and light adaptability, which was consistent with their high chlorophyll a/b values. Taken together, Ziwuling P. rockii had the strongest photosynthetic capacity among all tested sources, followed by Fengxiang P. ostii, and Xunyang P. ostii, which are recommended to be used as seed sources for oil peony cultivation and cross-breeding.

Seed yield and nutritional quality are dependent on seed development in oil crops. In a previous study, we showed that light shading improved seed yield and quality in oilseed peony, but the underlying mechanisms driving light shading impacts on seed yield and nutritional quality as mediated through seed development remain unclear. To develop an understanding of these mechanisms, oilseed peony trees were shaded by different density polyethylene nets starting at 28 days after pollination (DAP) and continuing until harvest. The seed volume, weight, and nutritional quality parameters, as well as the expression of genes related to the synthesis of unsaturated fatty acids (UFAs), were examined at 14-day intervals. Results showed that hundred-seed volume (Vh), fresh weight (Wf), and dry weight (Wd) increased by 8.2, 15.2, and 33.0 times, respectively, from 14 to 70 DAP. During the same period, the contents of starch, soluble protein, crude oil, and UFAs increased by 2.8, 3.7, 20.4, and 21.1 times, respectively. From 71 to 98 DAP, Vh, Wf, and Wd increased by 4.1, 5.4, and 20.8%, respectively. During this period, the contents of soluble protein, crude oil, and UFAs increased by 36.8, 51.4, and 49.5%, respectively. From 99 to 112 DAP, Vh, Wf, and Wd slightly increased, and the content of soluble protein increased by 25.2%. In contrast, the contents of soluble sugar, starch, and crude oil decreased by 28.3, 15.1, and 6.3%, respectively. Thus, seed development of oilseed peony can be divided into three periods of rapid growth (before 70 DAP), slow growth (71–98 DAP), and maturation (99–112 DAP). At 98 DAP, light shading increased the content of soluble sugar by 8.3%. At 112 DAP, light shading increased Vh, Wf, Wd, the content of crude oil, and UFAs by 6.9, 8.3, 8.3, 6.6, and 9.6%, respectively. The expression level of FAD2 in peony seed was up-regulated by 87.1 and 219.3% at 98 and 112 DAP, respectively. The expression level of FAD8 was up-regulated by 10.8, 71.7, 162.1, and 371.3% at 70, 84, 98, and 112 DAP, respectively. The expression level of SAD was up-regulated by 53.5 and 150.3% at 98 and 112 DAP, respectively. It is thus concluded that light shading significantly improved seed yield and nutritional quality parameters via increased seed growth and the expression of fatty acid desaturase genes during the slow growth and the maturation periods of seed development.

A novel and efficient adsorbent, iminodiacetic acid-functionalized Paeonia ostii seed coats (IDA-PSC), was prepared for the removal of copper ions from aqueous solution. Structural and morphologica...

Introduction The Paeonia ostii T. Hong & J. X. Zhang seed shell, characterised by a high content of oligostilbenes, is one of the two most important by-products in the preparation of seed oil. Oligostilbenes are considered characteristic constituents of the genus Paeonia, and can be used in fingerprinting to determine the geographical origin and the quality of raw materials. Objective To develop and optimise a simple and reproducible high-performance liquid chromatography diode array detection (HPLC-DAD) method for the simultaneous determination of seven oligostilbenes in P. ostii seed shell from different geographical areas, and to associate the cultivation area. Methodology A validated HPLC method coupled with a DAD detector was performed for the detection and determination of target compounds in the samples. Optimal chromatographic conditions were achieved using an Agilent Zorbax Eclipse SB-AQ-C18 column and a gradient elution with acetonitrile and potassium dihydrogen phosphate solution. Results The proposed quantitative method showed appropriate accuracy and precision, and was successfully applied to the routine analysis of seven oligostilbenes and the quality evaluation of 50 P. ostii seed shell samples. There were significant differences between the contents of the seven oligostilbenes in different samples (P Conclusion The results demonstrated that the oligostilbenes were main secondary metabolites in the P. ostii seed shells, and the content of seven components in P. ostii seed shells sourced from different cultivation areas in China was different.

Tree peony seeds oil (TPSO, Paeonia ostii) extracted at different roasting temperatures were studied for color, acid values, total phenols, fatty acid composition, antioxidant capacity, volatiles, and benzoic acid. Roasting led to increased antioxidant capacity and acid values. Headspace analysis of raw peony seed oil showed only six volatile compounds, while after roasting volatiles such as pyrazines, aldehydes and furans were observed and contributed to nutty aromas. Unsaturated fatty acids constituted more than 90% of the total fatty acids with α-linolenic acid as the predominant fatty acid of TPSO and was not significantly changed with roasting temperature. Benzoic acid concentration increased significantly as roasting temperature increased. Although the occurrence of benzoic acid in virgin oil might be a concern, it can be removed through refining for commercial production.

The plant transcription factor WRINKLED1 (WRI1), a member of AP2/EREBP, is involved in the regulation of glycolysis and the expression of genes related to the de novo synthesis of fatty acids in plastids. In this study, the key regulator of seed oil synthesis and accumulation transcription factor gene PoWRI1 was identified and cloned, having a complete open reading frame of 1269 bp and encoding 422 amino acids. Subcellular localization analysis showed that PoWRI1 is located at the nucleus. After the expression vector of PoWRI1 was constructed and transformed into wild-type Arabidopsis thaliana, it was found that the overexpression of PoWRI1 increased the expression level of downstream target genes such as BCCP2, KAS1, and PKP-β1. As a result, the seeds of transgenic plants became larger, the oil content increased significantly, and the unsaturated fatty acid content increased, which provide a scientific theoretical basis for the subsequent use of genetic engineering methods to improve the fatty acid composition and content of plant seeds.

Tree peony seed, traditionally used for edible oil production, is rich in α-linolenic acid. However, little attention is given to the fruit by-products during seed oil production. The present work aimed to comprehensively investigate the phytochemical constituents and multiple biological activities of different parts of tree peony fruits harvested from Paeonia ostii and Paeonia rockii. 130 metabolites were rapidly identified through UPLC-Triple-TOF-MS on the basis of MS/MS molecular networking. Metabolite quantification was performed through the targeted approach of HPLC-ESI-QQQ-MS. Eight chemical markers were screened via principal component analysis (PCA) for distinguishing species and tissues. Interestingly, two dominant compounds, paeoniflorin and trans-resveratrol, are specially localized in seed kernel and seed coat, respectively. Unexpectedly, the extracts of fruit pod and seed coat showed significantly stronger antioxidant, antibacterial, and anti-neuroinflammatory activities than seed kernel from both P. ostii and P. rockii. Our work demonstrated that tree peony fruit is promising natural source of bioactive components and provided its potential utilization in food and pharmaceutical industries.

Lipid components in the developing kernel of Paeonia ostii were determined, and the fatty acid (FA) distributions in triacylglycerol and phospholipids were characterized. The lipids in the kernel were mainly phospholipids (43%), neutral glycerides (24%), fatty acyls (26%), and sphingolipids (4.5%). The dominant neutral glycerides were TAG and diacylglycerol. The PL components included phosphatidic acid, phosphatidyl glycerol, phosphatidyl choline, phosphatidyl serine, phosphatidyl inositol, and phosphatidyl ethanolamine. As the kernel developed, the profiles of the molecular species comprising TAG and PL changed, especially during the earlier phases of oil accumulation. During rapid oil accumulation, the abundances of sphingosine-1-phosphate, pyruvic acid, stearic acid, and alpha-linolenic acid changed significantly; the sphingolipid metabolism and unsaturated FAs biosynthesis pathways were significantly enriched in these differentially abundant metabolites. Our results improve our understanding of lipid accumulation in tree peony seeds, and provide a framework for the analysis of lipid metabolisms in other oil crops.

Seed oils are of great economic importance both for human consumption and industrial applications. The nutritional quality and industrial value of seed oils are mostly determined by their fatty acid profiles, especially the relative proportions of unsaturated fatty acids. Tree peony seed oils have recently been recognized as novel edible oils enriched in α-linolenic acid (ALA). However, congeneric species, such as Paeonia ostii and P. ludlowii, showed marked variation in the relative proportions of different unsaturated fatty acids. By comparing the dynamics of fatty acid accumulation and the time-course gene expression patterns between P. ostii and P. ludlowii, we identified genes that were differentially expressed between two species in developing seeds, and showed congruent patterns of variation between expression levels and phenotypes. In addition to the well-known desaturase and acyltransferase genes associated with fatty acid desaturation, among them were some genes that were conservatively co-expressed with the desaturation pathway genes across phylogenetically distant ALA-rich species, including Camelina sativa and Perilla frutescens. Go enrichment analysis revealed that these genes were mainly involved in transcriptional regulation, protein post-translational modification and hormone biosynthesis and response, suggesting that the fatty acid synthesis and desaturation pathway might be subject to multiple levels of regulation.

Ethnopharmacological relevance Paeonia plants have been widely used as traditional Chinese medicinal materials for more than 2,000 years in the treatment of cardiovascular, extravasated blood and female genital diseases; paeoniflorin and paeonol have been implicated as the plants’ primary active ingredients. Aim of the study Previous studies have been singularly focused on the chemical constituents and content variation of the Paeonia roots in the advancement of traditional Chinese medicine, with the plants’ stems and leaves considered useless. This study aims to explore the chemical constituents, content variation, and antioxidant capacity in Paeonia stems and leaves for the future utilization of traditional Chinese medicine, given that current practices of digging and trade endanger Paeonia in the wild. Materials and methods Herein, secondary metabolites from the stems and leaves from six developmental stages of the annual growth cycle of Paeonia ostii T. Hong & J. X. Zhang, P. ‘Hexie’, and P. lactiflora Pall. were qualitatively and quantitatively analyzed via high-performance liquid chromatography with a diode array detector (HPLC-DAD) and high-performance liquid chromatography quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF-MS). Antioxidant capacity at each stage was also evaluated by various free radical scavenging assays. Results A total of 24 metabolites were detected and identified, including 5 monoterpene glycosides, 4 tannins, 5 phenols, 9 flavonoids, and paeonol. Excepting paeonol and the phenols, the levels of each metabolite category were significantly higher in the leaves than the stems during all developmental stages. The paeoniflorin content in the P. ostii leaves was the highest during the first developmental stage and higher than the standards of the Chinese Pharmacopoeia, suggesting it to be the optimal harvesting stage for medicinal uses. Notably, the antioxidant capacity of the leaves was significantly greater than in the stems, particularly for the leaves of P. ‘Hexie’. Conclusion Our study indicates that the leaves of P. ‘Hexie’ have the potential to be a worthy medicinal substitute to Paeonia roots due to their high monoterpene glycosides, phenols, and flavonoids as well as their strong antioxidant capacity. Further, this study provides a theoretical basis for the development and utilization of non-root Paeonia plant sections as medicinal plant resources.

Paeonia ostii seeds were identified as novel sources of edible plant oil with a high proportion of α-linolenic acid, a type of n-3 fatty acid with many health benefits. Due to the unreliability of seed oil content and quality, it is necessary to discover the mechanism underlying lipid biosynthesis in Paeonia ostii seeds. This study aimed to identify the key genes involved in lipid biosynthesis in Paeonia ostii seeds by analyzing the relationship among the seed characteristics and the expression patterns of lipid genes in Paeonia ostii during seed development. Preliminary research on Paeonia ostii seed development was carried out from 10 days after pollination until maturity, focusing on phenology, oil content and lipid profiles. In addition, we investigated the spatiotemporal expression of 36 lipid biosynthetic genes in Paeonia ostii by using quantitative real-time PCR. The results suggested that the development of Paeonia ostii seeds from pollination to maturity could be divided into three periods. The 36 lipid genes showed various spatiotemporal expression patterns and five gene groups with distinct temporal patterns during seed development were identified by clustering analysis of expression data. Furthermore, the relationships between gene expression and lipid/fatty acid accumulation and some candidate key lipid genes were discussed. This study provided the global patterns of fatty acid and lipid biosynthesis-related gene expression, which are critical to understanding the molecular basis of lipid biosynthesis and identifying the lipid accumulation rate-limiting genes during seed development.

Chalcone synthase (CHS) is the key enzyme in the flavonoid biosynthetic pathway and has been studied in many plants, but the function of the CHS gene has not been well characterized in Paeonia ostii. In this study, we obtained a CHS homologue gene from P. ostii, which possessed the putative conserved amino acids of chalcone synthase by multiple alignment analysis and demonstrated the highest expression in developing seeds. In vitro assays of the recombinant PoCHS protein confirmed enzymatic activity using malonyl-CoA and 4-coumaroyl-CoA as substrates, and the optimal pH and reaction temperature were 7.5 and 40°C, respectively. Furthermore, ectopic over-expression of PoCHS in Arabidopsis up-regulated the expression levels of genes involved in seed development (ABI), glycolysis (PKp2, PDH-E1a, and SUS2/3), and especially fatty acid biosynthesis (BCCP2, CAC2, CDS2, FatA and FAD3). This resulted in an increased unsaturated fatty acid content, especially α-linolenic acid, in transgenic Arabidopsis seeds. In this study, we examined the functions of CHS homologue in P. ostii and demonstrated its new function in seed fatty acid biosynthesis. This article is protected by copyright. All rights reserved.

Paeonia ostii is now being extensively planted for oil extraction in China, which is recognized as a single oil-use tree peony cultivar and commonly called 'Fengdan'. This study investigated the effects of nitrogen fertilizer on oil yield, fatty acid compositions and antioxidant activity of P. ostii. Oil yield (33.46 %), oleic acid (25.12 %), linoleic acid (29.21 %) and α-linolenic acid (43.12 %) reached the maximum at N450 treatment, with significant differences compared with other treatments (P

Tree peonies (Paeonia ostii and Paeonia rockii) are popular ornamental plants. Moreover, these plants have become oil crops in recent years. However, there are limited compositional studies focused on fatty acids. Therefore, this work aims to reveal compositional characteristics, regarding fatty acids, sterols, &gamma, tocopherol and phenolic compounds, of tree peony seed oils from all major cultivation areas in China, and to compare with herbaceous peony seed oil. For that, an integrative analysis was performed by GC-FID, GC-MS and UHPLC-Q-TOF-MS technologies. The main fatty acid was &alpha, linolenic acid (39.0&ndash, 48.3%), while &beta, sitosterol (1802.5&ndash, 2793.7 mg/kg) and fucosterol (682.2&ndash, 1225.1 mg/kg) were the dominant phytosterols. Importantly, 34 phenolic compounds, including paeonol and &ldquo, Paeonia glycosides&rdquo, (36.62&ndash, 103.17 &mu, g/g), were characterized in vegetable oils for the first time. Conclusively, this work gives new insights into the phytochemical composition of peony seed oil and reveals the presence of bioactive compounds, including &ldquo

Background Paeonia ostii is a potentially important oilseed crop because its seed yield is high, and the seeds are rich in α-linolenic acid (ALA). However, the molecular mechanisms underlying ALA biosynthesis during seed kernel, seed testa, and fruit pericarp development in this plant are unclear. We used transcriptome data to address this knowledge gap. Results Gas chromatograph-mass spectrometry indicated that ALA content was highest in the kernel, moderate in the testa, and lowest in the pericarp. Therefore, we used RNA-sequencing to compare ALA synthesis among these three tissues. We identified 227,837 unigenes, with an average length of 755 bp. Of these, 1371 unigenes were associated with lipid metabolism. The fatty acid (FA) biosynthesis and metabolism pathways were significantly enriched during the early stages of oil accumulation in the kernel. ALA biosynthesis was significantly enriched in parallel with increasing ALA content in the testa, but these metabolic pathways were not significantly enriched during pericarp development. By comparing unigene transcription profiles with patterns of ALA accumulation, specific unigenes encoding crucial enzymes and transcription factors (TFs) involved in de novo FA biosynthesis and oil accumulation were identified. Specifically, the bell-shaped expression patterns of genes encoding SAD, FAD2, FAD3, PDCT, PDAT, OLE, CLE, and SLE in the kernel were similar to the patterns of ALA accumulation in this tissue. Genes encoding BCCP, BC, KAS I– III, and FATA were also upregulated during the early stages of oil accumulation in the kernel. In the testa, the upregulation of the genes encoding SAD, FAD2, and FAD3 was followed by a sharp increase in the concentrations of ALA. In contrast, these genes were minimally expressed (and ALA content was low) throughout pericarp development. Conclusions We used three tissues with high, moderate, and low ALA concentrations as an exemplar system in which to investigate tissue-specific ALA accumulation mechanisms in P. ostii. The genes and TFs identified herein might be useful targets for future studies of ALA accumulation in the tree peony. This study also provides a framework for future studies of FA biosynthesis in other oilseed plants.

In order to analyze the interaction relationship between heavy metals and other mineral elements during the processes of absorption and translocation by plant grown on heavy metal-contaminated area, the concentrations of Cu, Zn, Mn, Cd, Pb, Ca, Mg, Fe, and K in the medicinal plant Paeonia ostii T. Hong et J. X. Zhang and its rhizospheric soil were determined, which grow around an abandoned copper tailings reservoir in Tongling City, China. Geo-accumulation index (Igeo) calculation indicated that Cu and Pb are the main pollution elements in the rhizospheric soil. Moreover, the Cu and Pb concentrations in the cortex moutan of P. ostii exceeded the maximum permissible limits for food product safety. The bioaccumulation factor values of the tested metals in plant roots were found < 0.50, with the exception of Ca (maximum 5.99). The translocation factor values of detected heavy metals Cd and Pb were more than 1.00, which indicated that P. ostii could be considered a potential accumulator plant for Cd and Pb. Significant positive correlations including Cu-Cd, Cu-Zn, Cu-Pb, Cd-Zn, Cd-Fe, Cd-Fe, Zn-Pb, Pb-Fe, Mn-Fe, and Ca-Mg in the cortex moutan and Cu-Zn, Cu-Fe, Zn-Mg, Zn-Fe, and Mn-K in the leaves were observed (P < 0.05). Significant positive correlation between Cu, Zn, Mg, and Fe was also confirmed in the processes of absorption and translocation from the soil to plant (P < 0.05), which evidenced that synergistic element interactions of the essential elements Cu, Zn, Mg, and Fe are a result of the similarity in their ionic radii and octahedral coordination geometry.

Paeonia ostii is known for its excellent medicinal values as Chinese traditional plant. To date, the diversity of culturable endophytes associated with P. ostii is in its initial phase of exploration. In this study, 56 endophytic bacteria and 51 endophytic fungi were isolated from P. ostii roots in China. Subsequent characterization of 56 bacterial strains by 16S rDNA gene sequence analysis revealed that nine families and 13 different genera were represented. All the fungal strains were classed into six families and 12 genera based on ITS gene sequence. The biosynthetic potential of all the endophytes was further investigated by the detection of putative polyketide synthase (PKS) and nonribosomal peptide synthetase (NRPS) genes. The PCR screens were successful in targeting thirteen bacterial PKS, five bacterial NRPS, ten fungal PKS and nine fungal NRPS gene fragments. Bioinformatic analysis of these detected endophyte gene fragments facilitated inference of the potential bioactivity of endophyte bioactive products, suggesting that the isolated endophytes are capable of producing a plethora of secondary metabolites. These results suggest that endophytes isolated from P. ostii had abundant population diversity and biosynthetic potential, which further proved that endophytes are valuable reservoirs of novel bioactive compounds. Paeonia ostii is known for its excellent medicinal values as Chinese traditional plant. To date, the diversity of culturable endophytes associated with P. ostii is in its initial phase of exploration. In this study, 56 endophytic bacteria and 51 endophytic fungi were isolated from P. ostii roots in China. Subsequent characterization of 56 bacterial strains by 16S rDNA gene sequence analysis revealed that nine families and 13 different genera were represented. All the fungal strains were classed into six families and 12 genera based on ITS gene sequence. The biosynthetic potential of all the endophytes was further investigated by the detection of putative polyketide synthase (PKS) and nonribosomal peptide synthetase (NRPS) genes. The PCR screens were successful in targeting thirteen bacterial PKS, five bacterial NRPS, ten fungal PKS and nine fungal NRPS gene fragments. Bioinformatic analysis of these detected endophyte gene fragments facilitated inference of the potential bioactivity of endophyte bioactive products, suggesting that the isolated endophytes are capable of producing a plethora of secondary metabolites. These results suggest that endophytes isolated from P. ostii had abundant population diversity and biosynthetic potential, which further proved that endophytes are valuable reservoirs of novel bioactive compounds.

Five novel globoscinic acid derivatives, aspergilates A-E (1-5) have been isolated from endophytic fungus Aspergillus sp. derived from Paeonia ostii. The structures of aspergilates A-E were determined by in-depth analyses of NMR spectra, HRESIMS and CD experiments. The absolute configurations of compounds 2-5 were determined by the ECD calculations based on quantum chemistry. Cytotoxic activities against five selected tested tumor cell lines of 1-5 were evaluated.

A novel effi cient adsorbent, alkali-pretreated Paeonia ostii seed coats (AP-PSC), was investigated for the removal of methylene blue (MB) dye from solution. Orthogonal array design was applied to optimize the process parameters viz. alkali concentration, liquid-solid ratio (LSR) and pretreatment time. The results revealed that the optimal pretreatment conditions were at 0.8% (w/w) NaOH with LSR of 0.35 L g-1 treating for 50 min. Equilibrium and kinetic studies indicated that Langmuir isotherm and Pseudo-second-order models described the experimental data well. The maximum adsorption capability was of 368.2 mg g-1 for MB at 25oC. Thermodynamic parameters suggested that the AP-PSC adsorption process was physical, endothermic and spontaneous. Furthermore, the adsorption process was infl uenced by several interactive mechanisms, including ion-exchange, as well as Van der Waals forces and hydrogen bonds that occur concomitantly. It was concluded that AP-PSC may be potential as an effi cient adsorbent to remove MB from solution.

Two new pyridine derivatives climacomontaninates A–B (1–2), and a new sesquiterpenoid derivative climacomontanetate (3), together with twelve known compounds (4–15) were isolated from the culture extract of the fungal strain Climacocystis montana from the root bark of Paeonia ostii. The structures of these compounds were determined through spectroscopic methods such as NMR and HRMS. Moreover, we expound the absolute configuration of 1 using the organic synthesis method. The cytotoxicity against five human cancer cell lines of new compounds were evaluated by SRB assay.

Tree peony seeds are rich in α-linolenic acid (ALA), and the peony seed oil is now being produced in China. Paeonia ostii is the most widely used tree peony species for oil extraction, which is commercially called Fengdan and treated as a single cultivar. Here, 50 P. ostii individuals from the same population in northern China were randomly selected for fatty acids (FAs) analysis. Thirteen FAs were isolated, and the most abundant five were palmitic acid (5.31–6.99%), stearic acid (1.22–2.76%), oleic acid (18.78–28.15%), linoleic acid (11.86–26.10%), and ALA (41.11–57.51%). There were significant individual differences of plants in FA quality and quantity and the linoleic acid content in Plant No. 48 even exceeded the scope of 1–99%. Further statistical analysis indicated that most of the individual FAs, saturated FAs, unsaturated FAs, and total FAs levels showed significant positive correlations to each other, whereas the seed yield per plant was independent and not correlated to the factors mentioned above. Ward's hierarchical clustering results grouped the 50 plants into four clusters based on FA contents and seed yield, and the seven plants in Cluster IV were identified as good candidates for oil production. Our results confirmed that the individual differences did occur in P. ostii and Fengdan cannot be simply treated as one uniform cultivar. Also, these results may help simplify the selection of plants for oil peony breeding and accelerate the development of the oil peony industry.

Tree peony seed is unique for its super-high content of unsaturated fatty acid and is thus considered as an important source of woody oil. However, photosynthetic production is greatly reduced under high light intensity and air temperature during the seed filling period, which negatively affects seed yield and quality. The objective of this study was to determine if appropriate shading improves yield and quality of seed in oilseed peony. In this study, oilseed peony trees were shaded by different density polyethylene nets from four weeks after flowering to harvest stages to form light, moderate, and severe shadings, equivalent to about 80, 40, and 20% of full solar exposure, respectively. The effects of different shadings on some physiological parameters, yield and yield components, and nutritional composition of seed were examined. Averaged across two years, light shading increased the actual net photosynthetic rate ( P n ) by 16.8%, the maximum net photosynthetic rate ( P max ) by 81.4%, chlorophyll (Chl) content by 52.8%, auxin (IAA) content by 38.1%, and gibberellic acid (GA 3 ) content in leaves by 6.3%; it decreased the accumulation of H 2 O 2 in leaves by 24.8%, malondialdehyde (MDA) by 22%, and endogenous abscisic acid (ABA) by 8.8%, indicating that leaf senescence in late season was considerably delayed. Light shading increased seed yield, and contents of crude fat and unsaturated fatty acids by 9.7, 5.6, and 9.6%, respectively, while moderate or severe shading significantly reduced all the three parameters. Light shading increased seed weight, but moderate or severe shading reduced seed weight or follicle density. The improved seed yield under light shading was mainly due to increased seed weight, while the reduced seed yield under moderate or severe shading was mainly attributed to reduce follicle density and seed weight. The improved seed weight and content of unsaturated fatty acids under light shading was possibly due to the delayed leaf senescence. The overall results indicated that light shading is beneficial to yield and quality parameters of seed in oilseed peony. Cultivating oilseed peony under a light shading environments such as partially closed forests would better increase total output and income per unit land area than that under full solar exposure.

Seed germination is a critical process that is influenced by various factors. In the present study, the effect of low temperature (4 °C) on tree peony seed germination was investigated. Compared to seeds maintained at 25 °C, germination was inhibited when seeds were kept at 4 °C. Furthermore, low-temperature exposure of seeds resulted in a delay in water uptake, starch degradation, and soluble sugar consumption and a subsequent increase in soluble protein levels. Two-dimensional gel electrophoresis (2-DE) proteomic analysis identified 100 protein spots. Comparative analysis indicated that low-temperature exposure apparently mainly affected glycolysis and the tricarboxylic acid (TCA) cycle, while also significantly affecting proteometabolism-related factors. Moreover, low-temperature exposure led to the induction of abscisic acid, whereas the gibberellin pathway was not affected. Further comparison of the two temperature conditions showed that low-temperature exposure delays carbohydrate metabolism, adenosine triphosphate (ATP) production, respiration, and proteolysis and increases defense response factors. To further examine the obtained proteomic findings, four genes were evaluated by quantitative polymerase chain reaction (qPCR). The obtained transcriptional results for the GAPC gene coincided with the translational results, thus further suggesting that the delay in glycolysis may play a key role in low-temperature-induced inhibition of seed germination. However, the other three genes examined, which included FPP synthase, PCNT115, and endochitinase, showed non-correlative transcriptional and translational profiles. Our results suggest that the exposure of tree peony seeds to low temperature results in a delay in the degradation of starch and other metabolites, which in turn affects glycolysis and some other processes, thereby ultimately inhibiting seed germination.

The influence of the foliage boron(B)-spaying concentration on the yield and fatty acid composition of tree peony (Paeonia ostii ‘Feng Dan’) was explored in the experiment of 2014-2015. In this research, a statistically significant correlation was found between the mass concentration of foliage boron- spraying and tree peony seed yield. Maximum yield increment of tree peony seeds was obtained when the boron-spraying concentration was 4 g/L. The composition of fatty acid was analyzed by gas chromatography-mass spectrometry (GC-MS), and the main components of the fatty acid composition were quantified by internal standard method. The increase in the oil extraction rate after foliage boron-spraying nutrition of different concentration was significant and ranged between 0.04% and 11.43%. Seed oil production and oil extraction rate were also increased due to the increase of seed yields. Furthermore, foliage boron-spraying had a significant effect on the content of linolenic acid and linoleic acid in seed oil.

Paeonia ostii var. lishizhenii has emerged as a valuable oil-producing crop with splendid characteristic of high α-linolenic acid (C18:3, ALA) content in its seed oil for healthy food supplement, but the molecular mechanism for seed ALA accumulation remains enigmatic. In our previous report, a PoSAD gene encoding stearoyl-ACP desaturase had been cloned and functional charactered for the first desaturation procedure involved in ALA biosynthesis pathway in P. ostii var. lishizhenii endosperms, while other participants have not been identified to date. In this study, full-length cDNAs of PoFAD2 (1489 bp), PoFAD6 (1638 bp), and PoFAD3 (1709 bp) were isolated based on our recent transcriptome sequencing data. Bioinformatic analyses revealed that the PoFADs were closest to their counterparts from Paeoniaceae species P. ludlowii, P. rockii, and P. suffruticosa in phylogenetic tree, which shared highly conserved histidine boxes (HXXXH, HXXHH, and HXXHH), exhibiting typical characters of membrane-bound desaturases in higher plants. Additionally, the PoFAD2 and PoFAD3 were specifically expressed and highly associated with LA and ALA accumulation in developing endosperms, whereas PoFAD6 expression has no significantly difference during whole seed developing stages. The catalytic function of these PoFADs were further analyzed by heterologous expression in Saccharomyces cerevisiae and Arabidopsis thaliana. The results showed that PoFAD2 and PoFAD6 could catalyze linoleic acid (C18:2) synthesis, while PoFAD3 had ability to produce ALA. This study functional identified three PoFAD genes, which indicates their critical roles in ALA biosynthesis pathway in P. ostii var. lishizhenii, and is of great theoretical and practical meaning on breeding and cultivating new tree peony varieties to promote human health and nutrition supplement.

In this study, oil-in-water microemulsions (MEs) were developed and used as a stable carrier for delivery of Paeonia ostii seed oil (PSO), a fatty acid mixture (FAM), and α-linolenic acid (ALA). Dynamic light scattering (DLS) was used to measure the particle size and polydispersity index (PDI) of the ME. The effects of temperature, exposure to light, and the addition of antioxidants on the peroxide values of the loads were investigated. The MEs were composed of droplets with diameters between 15 and 35 nm and PDIs lower than 0.5, and the addition of antioxidants had no significant effect on the particle size and dispersibility. Temperature, more than light, was the factor that most significantly promoted doxidation, and the influence of the addition of different antioxidants was higher by butylated hydroxytoluene (BHT), followed by vitamin C and vitamin E. Viability and morphology of A549 human lung adenocarcinoma cells treated with MEs were studied. The three evaluated MEs caused damage to cell membrane and inhibited the growth of cancer cells in a dose-dependent manner. Data on intracellular malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in cancer cells indicated that the treatment with MEs stimulated oxidative stress response and induced oxidative damage. These findings showed the latent capacity of MEs for protection of nutritional factors and for drug delivery.

Paeonia ostii is a widely cultivated medicinal and oilseed crop in China. The stamens of P. ostii are important by-products of this crop and conventionally used as tea with putative beneficial effects on human health. However, the in-depth understanding of P. ostii stamens is scarce. In this study, comparative analysis was carried out to systematically characterize the bioactive constituents and biological activities of P. ostii stamens from different geographical regions of China. Seventy-seven secondary metabolites were tentatively identified through untargeted metabolomic analysis based on MS/MS molecular similar networking and other approaches. Targeted metabolomics conjugated with principal component analysis revealed that eight bioactive compounds, including oxypaeoniflorin, pentagalloyl glucose (PGG), paeoniflorin, and albiflorin, were the primary chemical markers for quality control. Habitats substantially affected the content of PGG, and geographical factor of Nujiang (Southern China) significantly promoted the accumulation of PGG. The extracts from peony stamens across all geographical regions exhibited potent antioxidant, antibacterial, antitumor, and anti-neuroinflammation properties, which were strongly correlated with bioactive compounds. Our results provide new insights into P. ostii stamens to be used for pharmaceutical purposes.

Phytochemical investigation into the seeds of Paeonia ostii T. Hong et J. X. Zhang (Paeoniaceae) led to the identification of three new aromatic monoterpenoid glycosides, named paeostisides A-C (1-3), along with one known compound. Their structures were identified by spectroscopic analysis and chemical method.

The accumulation of chemical constituents of some medicinal plants, such as Paeonia ostii T. Hong et J. X. Zhang, Houpo&euml, a officinalis (Rehder and E. H. Wilson) N. H. Xia and C. Y. Wu. and Atractylodes lancea (Thunb.) DC, can precipitate on the surface and form frosts after natural or artificial intervention. The characteristics of these three medicinal plants and their frosts were analyzed by light microscope, polarizing microscope, stereomicroscope, and metalloscope. The results of ordinary Raman of P. ostii and H. officinalis showed that the frosts of P. ostii matched paeonol, while that of H. officinalis matched magnolol and honokiol. In P. ostii and its frost, 19 peaks were identified by UPLC-Q/TOF-MS, and the main component was paeonol. Eleven components were identified in H. officinalis and its frosts, and the main components were magnolol and honokiol. A. lancea and its frosts were analyzed by gas chromatography-mass spectrometry (GC-MS), 21 were identified, and its main components were hinesol and &beta, eudesmol. These three medicinal plants accumulate compounds and precipitate frosts on the surface. The results show that the components of the frosts provide a basis for quality evaluation and research on similar medicinal plants, and reveals the scientific connotation of &ldquo, taking the medicinal materials&rsquo, precipitated frosts as the best&rdquo, of P. ostii, H. officinalis, and A. lancea, to some extent.

Paeonia ostii is an emerging woody oil crop and cultivated on a large scale in China. This study attempted to characterize the characteristics of P. ostii seed oil body (OB) and found the key genes related to its morphology. The results showed that P. ostii seed oil contained five dominant fatty acid compositions that were stored in OBs. During the development of seeds, oil yield and fatty acid content were in line with OB accumulation. Moreover, NaCl concentration and pH value could influence P. ostii OB stability. Additionally, oleosins (OLEs) were identified as the most abundant proteins in OBs. Based on the expression levels of OLEs, PoOLE17.5 was isolated, which might be localized in OBs. And overexpression of PoOLE17.5 in tobacco obviously increased seed size and hundred-seed weight, altered OB morphology and increased fatty acid content. These results could provide a theoretical basis for improving oil yield of P. ostii seeds.

The seeds of tree peony (Paeonia ostii) are promulgated as emerging edible oil crops. However, biological properties of principal constituents of peony seeds were not well studied. Fifteen main constituents including suffruticosols A and B, trans-e-viniferin, ampelopsin E, resveratrol, trans-resveratrol-4'-O-β-d-glucopyranoside, paeoniflorin, luteolin, luteolin-4'-O-β-d-glucopyranoside, apigenin, kaempferol, oleanic acid, betulinic acid, hederagenin, and caffeic acid were isolated and identified. Their cytotoxicity against human tumor cell lines (COLO205, HT-29, HepG2, AGS, and HL-60) were evaluated. Among them, trans-e-viniferin showed the most potent cytotoxicity against HL-60 cells (IC50 5.6 μM); ampelopsin E exhibited the most obvious antiproliferative properties on COLO205 (IC50 78.1 μM) and HT-29 (IC50 4.2 μM) cells, and betulinic acid showed the strongest growth inhibitory effects on HepG2 (IC50 6.6 μM) and AGS (IC50 5.4 μM) cells. Three enzymes (tyronsinase, α-glucosidase, and acetylcholinesterase) inhibitory activities of 12 compounds were also screened. Stilbene compounds, especially suffruticosols A and B, showed a significant inhibitory activity on all three enzymes. PRACTICAL APPLICATIONS: The cytotoxicity of 15 main constituents from peony seeds against COLO205, HT-29, HepG2, AGS, and HL-60 cells were evaluated. Among them, trans-e-viniferin showed the most potent cytotoxicity against HL-60 cells (IC50 5.6 μM); ampelopsin E exhibited the most obvious antiproliferative properties on COLO205 (IC50 78.1 μM) and HT-29 (IC50 4.2 μM) cells, and betulinic acid showed the strongest growth inhibitory effects on HepG2 (IC50 6.6 μM) and AGS (IC50 5.4 μM) cells. Collectively, these results suggested that Paeonia ostii seed (POS) extracts are potential candidates for anticancer agents.

Antioxidant peptides derived from natural products have superior performance and broader application prospects. In this study, five novel antioxidant peptides were prepared from Paeonia ostii (P. ostii) seed meal, moreover the bioactive and the relationship between structure and properties of antioxidant peptides were elucidated by quantum chemical calculations. The free radical-scavenging activities were used as indexes to purify and concentrate the antioxidant peptides through five proteases and separation techniques. FSAP (Phe-Ser-Ala-Pro), PVETVR (Pro-Val-Glu-Thr-Val-Arg), QEPLLR (Gln-Glu-Pro-Leu-Leu-Arg), EAAY (Glu-Ala-Ala-Tyr) and VLRPPLS (Val-Leu-Arg-Pro-Pro-Leu-Ser) were identified by nano liquid chromatography&ndash, tandem mass spectrometry (LC-MS/MS). In vitro antioxidant activity test, EAAY exhibited the highest 2, 2&rsquo, azino-bis (ABTS) and hydroxyl radical-scavenging activity of 98.5% &plusmn, 1.1% and 61.9% &plusmn, 1.3%, respectively (p &lt, 0.01), at 0.5 mg/mL. In silico calculations were carried out using the density functional theory (DFT) with the B3LYP/6-31G* basis set. According to natural bond orbital (NBO) analysis, the bioactivity of free-radical scavenging of the peptides was presumed. Moreover, the antioxidant peptides demonstrated no obvious cytotoxicity to L929 fibroblast cells. Therefore, the peptides from P. ostii seed by-products might potentially have excellent uses in functional foods, nutraceuticals and pharmacological products.

Tree peony seed is a novel resource of edible oil with high α-linolenic acid (ALA) content (> 40%). To assess whether pollen sources influence the seed oil quality, fatty acids of hybrids from the combination of Paeonia ostii ‘Feng Dan’ and 30 cultivars were monitored and evaluated in this study. The results indicated that the content of total fatty acid and ALA ranged from 21.23 to 29.68% and from 46.75 to 64.71%, respectively. Thirty combinations were classified into four clusters. Cluster IV including ‘Tian Xiang Jin’, ‘Zhou Ban Hong’, ‘Xiang Yang Hong’ and ‘Yu Jie’ were good pollen donors because their hybrid seeds possessed the highest contents of ALA and unsaturated fatty acids, with an average of 159.39 mg g−1 and 263.76 mg g−1, respectively. This study provides a good base for breeding new cultivars with excellent edible oil and essential fatty acid contents for food.

Tree peony (Paeonia suffruticosa Andr.) is a popular ornamental plant around the world, which is known for its distinctively large and fragrant flowers. However, the underlying molecular mechanism of floral fragrance synthesis in tree peony remains poorly understood. In this study, integrative volatile profiling and RNA sequencing were conducted in four wild tree peony species: Paeonia ostii, Paeonia rockii, Paeonia delavayi and Paeonia lutea. A total of 67 floral volatiles were identified through gas chromatography-mass spectrometry (GC–MS) analysis. Terpenes were most abundant volatiles in P. ostii and P. rockii, while benzenoids content were relatively higher in P. delavayi and P. lutea. Transcriptome data revealed 17,967 differential expression genes (DEGs), 116 and 147 of which were found be related to the accumulation of terpenes and benzenoids, respectively. Specifically, 1-deoxy- d -xylulose 5-phosphate synthase, geranyl pyrophosphate synthase, farnesyl pyrophosphate synthase and terpene synthase may be the major regulators of floral terpenes biosynthesis in P. ostii and P. rockii, whilst 3-deoxy-7-phosphoheptulonate synthase, phenylalanine ammonialyase, cinnamate: CoA ligase and short-chain dehydrogenases/reductases may control the production of benzenoids production in P. delavayi and P. lutea. Taken together, results from this study sheds light on the molecular mechanism of fragrance variation among different tree peony species and also provides a valuable resource to investigate floral fragrance formation in tree peony.

Paeonia ostii is an emerging woody oil crop, but drought severely inhibits its growth and promotion in arid or semiarid areas, and little is known about the mechanism governing this inhibition. In this study, the full-length cDNA of a caffeoyl-CoA O-methyltransferase gene (CCoAOMT) from P. ostii was isolated, and determined to be comprised of 987 bp. PoCCoAOMT encoded a 247-amino acid protein, which was located in the nucleus and cytosol. Significantly higher PoCCoAOMT transcription was detected in P. ostii treated with drought stress. Subsequently, the constitutive overexpression of PoCCoAOMT in tobacco significantly conferred drought stress tolerance. Under drought stress, transgenic lines exhibited lower reactive oxygen species (ROS) accumulation, and higher antioxidant enzyme activities and photosynthesis. Moreover, the expression levels of senescence-associated genes were significantly downregulated, whereas the expression levels of lignin biosynthetic genes and PoCCoAOMT were significantly upregulated in transgenic lines. Similarly, transgenic lines produced significantly higher lignin, especially guaiacyl-lignin. These results suggest that PoCCoAOMT is a vital gene in promoting lignin synthesis and ROS scavenging to confer drought stress tolerance in P. ostii.

Paeonia ostii var. lishizhenii has been approved as a woody oil crop with the outstanding characteristic of abundant α-linolenic acid (C18:3, ALA) in its seed oil. The stearoyl-ACP desaturase gene (SAD) regulates the first key step from stearic acid (C18:0, SA) to oleic acid (C18:1, OA) in the ALA biosynthetic pathway, but its functional characterization in P. ostii var. lishizhenii is absent to date. In this study, a key PoSAD gene (1719 bp in length) was acquired from endosperm of P. ostii var. lishizhenii by transcriptome sequencing analysis and the RACE (rapid-amplification of cDNA ends) method. Bioinformatic analysis of the PoSAD protein showed high homology (ranging from 90.4% to 94.4%) and similar physical and chemical properties to SAD from other higher plants, indicating that it encodes a putative stearoyl-ACP desaturase. Analysis of cis-acting elements found several endosperm tissue-specific motifs; i.e., one Prolamin box, thirteen DOFCOREs and one RY repeat in its promoter. The results of the qRT-PCR experiments verified that PoSAD was most highly expressed in developing endosperm at 59 days after pollination (53.7 times that in shoots) compared with that in roots (1.4 times), stems (2.5 times), leaves (3.1 times), petals (13.1 times) and stamens (46.0 times). Meanwhile, the fatty acid contents in P. ostii var. lishizhenii endosperm at seven growth stages were compared with variation in PoSAD expression. Heterologous expression of PoSAD significantly decreased SA and increased OA content, which effectively reduced the ratios of SA to OA in Saccharomyces cerevisiae and Arabidopsis thaliana. However, contents and ratios of palmitic acid (C16:0) and palmitoleic acid (C16:1) were stable in transgenic yeast, and palmitoleic acid remained absent in transgenic A. thaliana seeds. These results illustrate that PoSAD plays an essential role in endosperm development of P. ostii var. lishizhenii, strictly in catalysis of SA desaturation and OA biosynthesis but without functioning in PA desaturation. The results contribute to our understanding of the characterization of PoSAD in OA biosynthesis in P. ostii var. lishizhenii.

Stamen from Paeonia ostii 'Fengdan Bai' and Paeonia rockii is rich in phenolic compounds and popularly used as tea materials with various pharmaceutical functions. In order to investigate whether stamen from other tree peony cultivars could be used as a natural antioxidant, the quality of stamen from thirty-five cultivars collected from the same garden was evaluated based on their phenolic composition and content by high-performance liquid chromatography analysis and in vitro antioxidant properties coupled with comprehensive chemometrics analysis. The results revealed that phenolic contents and antioxidant capacities of tree peony stamen were unique and cultivar dependent. Stamen from 'Zi Erqiao' exhibited the highest total phenolic and flavonol content, and strongest antioxidant activities, while that of 'Fengdan Bai' and P. rockii were at below-average levels among test samples. Further, thirty-seven cultivars of tree peony were divided into three major groups with a significant difference in total metabolites content and antioxidant properties, which were mainly contributed by six phytochemical compounds. Among these, naringin and benzoylpaeoniflorin were found to be critical chemical markers for the identification of tree peony stamen with high quality by chemometric analysis. Moreover, correlation analysis suggested that stamen from the earlier flowering cultivars with the hidden pistil, double petal, shorter thrum, more carpel and volume were possibly of higher quality. Together, cultivars with stamen enriched in phenolics and antioxidants properties, and their relevant critical phenotypic and phytochemical traits were screened out. This study would benefit the rapid identification of tree peony stamen with high quality and provide a valuable reference for its development and utilization as functional foods and pharmaceutical resources.

As a residue of oil processing, research about Paeonia ostii cake has not been reported. We used six enzymes to hydrolyze the Paeonia ostii cake and obtained six enzymatic polypeptides. The enzymatic polypeptide yields of the six methods were between 10.0 and 25.0 % and average molecular weight was between 3.0 and 10.0 kDa. The average particle size of six enzymatic polypeptides was less than 1000.0 nm. The enzymatic hydrolysis method had a significant effect on the surface morphology of the enzymatic residues. The enzymatic polypeptide from alkaline protease method had better thermal stability and stronger infrared absorption. The eight essential amino acid contents of six enzymatic polypeptides from pepsin, papain, neutral protease, protemax, trypsase and alkaline protease method were 14.7, 13.3, 14.2, 12.8, 13.8 and 15.0 %, and hydrophobic amino acid contents were 14.7, 14.2, 14.2, 13.9, 13.7 and 15.1 %, respectively. Among the 12 non-essential amino acids, only glutamine and asparagine were absent. In addition, the different amino acid increment in six enzymatic polypeptides was significantly different. Among them, cysteine had the largest increment, followed by glycine and glutamic acid. By 5-axe cobweb chart method, the enzymatic polypeptide from alkaline protease method was proved to have the strongest comprehensive antioxidant activity. The enzymatic polypeptides of alkaline protease and protemax method had stronger inhibition activity of α-glucosidase and α-amylase. In general, the enzymatic polypeptide from alkaline protease method had good antioxidant activity and physiological activity. Our research will provide basic data support for new potential applications of enzymatic polypeptide from peony cake and increase the added value of Paeonia ostii processing enterprises.