Fatty Acid Composition, Phytochemistry, Antioxidant Activity on Seed Coat and Kernel of Paeonia ostii from Main Geographic Production Areas

iTRAQ proteome analysis reveals the underling mechanisms of foliage zinc-spraying to improve photosynthetic capacity and seed yields of Peaonia ostii 'Fengdan'

Zinc (Zn) deficiency is a significant nutritional limitation to crop yield globally, particularly in calcareous soil environments. Tree peony of Peaonia ostii 'Fengdan' is regarded as an oil crop due to its seeds rich in alpha-linolenic acid, a beneficial compound for health promotion. However, low seed yield remains a primary challenge in attaining sufficient seed oil from tree peony. In this study, Zn fertilization was applied to soil or foliage of P. ostii 'Fengdan' in the growth period before fruit development. Our findings reveal that foliar Zn-spraying, as opposed to soil application, proves to be a more effective method for augmenting seed yield, Zn accumulation and photosynthetic capacity in 'Fengdan'. Comparative analyses of the leaf proteome of 'Fengdan' using iTRAQ profiling under foliar Zn-spraying identified 115 differentially expressed proteins (DEPs), including 36 upregulated proteins, which likely contribute to the observed increase in seed yields of 'Fengdan' caused by foliage Zn-spraying. Specifically, Zn2+ stimulation of phosphatidylinositol signaling initiates a cascade of metabolic regulations. Firstly, ATP synthesis promotes leaf photosynthetic capacity, facilitated by improved sucrose metabolism through upregulated pullulanase and 1,4-alpha-glucan-branching enzyme. Furthermore, lipid synthesis and transport are facilitated by upregulated lipoyl synthase and plastid lipid-associated proteins. Additionally, DEPs involved in secondary metabolism are upregulated in the production of various metabolites conducive to 'Fengdan' growth. Overall, our results demonstrate that foliage Zn-spraying enhances seed yield in P. ostii 'Fengdan' by elevating Zn content and secondary metabolite synthesis in leaves, thereby augmenting leaf photosynthetic capacity and lipid synthesis. This study provides an effective way to increase seed yield of tree peony by exogenous Zn application.

Microemulsions based on Acer truncatum seed oil and its fatty acids: fabrication, rheological property, and stability

AIMS

To construct the microemulsion delivery system (ME) loading ATSO and NA and study their physicochemical characteristics to enhance their stability and water solubility.

METHODS

By plotting ternary phase diagrams, the composition and proportions of the MEs were determined. The physicochemical characteristics and stability of MEs were evaluated by mean diameter, polydispersity index (PDI), pH, electrical conductivity, transmission electron microscopy (TEM), rheological behaviour measurement, and phase inversion temperature (PIT).

RESULTS

The MEs was composed with EL-40 as a surfactant and specifically with the addition of ethanol as a cosurfactant in NA-loaded ME. The mean diameters of ATSO-loaded ME and NA-loaded ME were 39.65 ± 0.24 nm and 32.90 ± 2.65 nm, and PDI were 0.49 ± 0.01 and 0.28 ± 0.14, respectively. The TEM confirmed the spherical and smooth morphology of MEs. The rheological results indicated that MEs are dilatant fluids with the advantages of low viscosity, high fluidity, and tolerance to temperature fluctuations. The mean diameter and PDI of MEs showed no significant change after storage at 25 °C for 28 days and centrifugation.

CONCLUSION

The prepared microemulsions could expand the application prospects of ATSO and NA products in cosmetics, medicine, foods and other fields.

Integrated analysis of metabolome, transcriptome, and bioclimatic factors of Acer truncatum seeds reveals key candidate genes related to unsaturated fatty acid biosynthesis, and potentially optimal production area

BACKGROUND

Lipids found in plant seeds are essential for controlling seed dormancy, dispersal, and defenses against biotic and abiotic stress. Additionally, these lipids provide nutrition and energy and are therefore important to the human diet as edible oils. Acer truncatum, which belongs to the Aceaceae family, is widely cultivated around the world for its ornamental value. Further because its seed oil is rich in unsaturated fatty acids (UFAs)- i.e. α-linolenic acid (ALA) and nervonic acid (NA)- and because it has been validated as a new food resource in China, the importance of A. truncatum has greatly risen. However, it remains unknown how UFAs are biosynthesized during the growth season, to what extent environmental factors impact their content, and what areas are potentially optimal for their production.

RESULTS

In this study, transcriptome and metabolome of A. truncatum seeds at three representative developmental stages was used to find the accumulation patterns of all major FAs. Cumulatively, 966 metabolites and 87,343 unigenes were detected; the differential expressed unigenes and metabolites were compared between stages as follows: stage 1 vs. 2, stage 1 vs. 3, and stage 2 vs. 3 seeds, respectively. Moreover, 13 fatty acid desaturases (FADs) and 20 β-ketoacyl-CoA synthases (KCSs) were identified, among which the expression level of FAD3 (Cluster-7222.41455) and KCS20 (Cluster-7222.40643) were consistent with the metabolic results of ALA and NA, respectively. Upon analysis of the geographical origin-affected diversity from 17 various locations, we found significant variation in phenotypes and UFA content. Notably, in this study we found that 7 bioclimatic variables showed considerable influence on FAs contents in A. truncatum seeds oil, suggesting their significance as critical environmental parameters. Ultimately, we developed a model for potentially ecological suitable regions in China.

CONCLUSION

This study provides a comprehensive understanding of the relationship between metabolome and transcriptome in A. truncatum at various developmental stages of seeds and a new strategy to enhance seed FA content, especially ALA and NA. This is particularly significant in meeting the increasing demands for high-quality edible oil for human consumption. The study offers a scientific basis for A. truncatum's novel utilization as a woody vegetable oil rather than an ornamental plant, potentially expanding its cultivation worldwide.

Phenolic compounds, antioxidant activity and sensory evaluation of sea buckthorn (Hippophae rhamnoides L.) leaf tea

Sea buckthorn leaf tea, an emerging potential functional beverage product, has not yet had appropriate product standards and corresponding quality evaluation methods, and its poor taste directly affects the acceptance of the population, thus limiting its market consumption potential. In this study, two major packaging forms of sea buckthorn leaf tea available in the Chinese market were selected. The contents of total phenolics, total flavonoids, and 10 phenolic compounds, as well as the in vitro antioxidant capacity and sensory characteristics of sea buckthorn leaf tea were analyzed. Results showed that the quality of sea buckthorn leaf tea in the Chinese market varied widely. The total phenolic content, total flavonoid content, antioxidant activity, and consumer acceptance of bagged sea buckthorn leaf tea were higher than those of bulk sea buckthorn leaf tea. Multifactorial statistical analysis showed that the taste astringency of sea buckthorn leaf tea was closely related to ellagic acid and isorhamnetin-3-O-neohesperidin. Furthermore, isorhamnetin-3-O-neohesperidin had a greater effect on the antioxidant activity of sea buckthorn leaf tea. Therefore, ellagic acid and isorhamnetin-3-O-neohesperidin can be used as potential quality markers for sea buckthorn leaf tea. This work provides a reference for taste improvement and quality control of sea buckthorn leaf tea.

Health benefits of flaxseed and its peptides (linusorbs)

Flaxseed (Linum usitatissimum L.) has been associated with numerous health benefits. The flax plant synthesizes an array of biologically active compounds including peptides or linusorbs (LOs, a.k.a., cyclolinopeptides), lignans, soluble dietary fiber and omega-3 fatty acids. The LOs arise from post-translational modification of four or more ribosome-derived precursors. These compounds exhibit an array of biological activities, including suppression of T-cell proliferation, excessive inflammation, and osteoclast replication as well as induction of apoptosis in some cancer cell lines. The mechanisms of LO action are only now being elucidated but these compounds might interact with other active compounds in flaxseed and contribute to biological activity attributed to other flax compounds. This review focuses on both the biological interaction of LOs with proteins and other molecules and comprehensive knowledge of LO pharmacological and biological properties. The physicochemical and nutraceutical properties of LOs, as well as the biological effects of certain LOs, and their underlying mechanisms of action, are reviewed. Finally, strategies for producing LOs by either peptide synthesis or recombinant organisms are presented. This review will be the first to describe LOs as a versatile scaffold for the action of compounds to deliver physiochemically/biologically active molecules for developing novel nutraceuticals and pharmaceuticals.

Assessing the Quality of Burkina Faso Soybeans Based on Fatty Acid Composition and Pesticide Residue Contamination

Soybean is widely used in the food industry because of its high fatty acid and protein content. However, the increased use of pesticides to control pests during cultivation, in addition to being a public health concern, may influence the nutritional quality of soybeans. This study aimed to assess the nutritional quality of soybeans with respect to fatty acid profile and pesticide residue contamination. The levels of fatty acids and pesticides in soybean varieties G196 and G197 were determined by gas chromatography and by the QuEChERS method, respectively. The results showed a significant variation in the quantitative and qualitative fatty acid composition of the two varieties, with 18.03 g/100 g and 4 fatty acids detected for the G196 variety and 21.35 g/100 g and 7 fatty acids for the G197 variety, respectively. In addition, 12 active pesticide compounds were found, and among them, imazalil, quintozene, cyfluthrin and lindane exceeded their maximum limits. The G197 variety had a better nutritional profile compared to G196. The profile of fatty acids and the content of pesticide residues were used as important determinants for soybean utilization in human nutrition.

Ultrasonic-assisted extraction and adsorption separation: Large-scale preparation of trans-ε-Viniferin, suffruficosol B and trans-Gnetin H for the first time

In this study, a Standard Operating Procedure (SOP) for the large-scale extraction, enrichment, and separation of suffruticosol B (SB), trans-ε-Viniferin (TV), trans-gnetin H (TG) from oil tree peony seeds shell (PSS) was successfully constructed. The ultrasonic-assisted extraction (UAE), macroporous adsorption resin (MAR), and column chromatography (CC) were employed to extract, enrich and separate SB, TV and TG from PSS, and the conditions were optimized. The results implied that SB (1.6937 g), TV (0.5884 g) and TG (3.8786 g) with the purity of 99.67 %, 99.32 % and 98.54 %, respectively, were obtained after the extraction, enrichment and separation. The total yields of the SB, TV and TG were 0.61 mg/g, 0.02 mg/g and 6.64 mg/g with the total extraction rates at 70.55 %, 69.77 % and 78.36 %, respectively. This is the first report on the large-scale extraction, enrichment and separation of oligostilbenes. The SOP in this paper could produce high purity SB, TV and TG, and provide a new idea for PSS as a new oligostilbene resource. The study expands the new development and research field of PSS and provides theoretical support for the green utilization of oil tree peony.

Optimization technology and kinetic studies of Acer truncatum seed oil saponification and crystallization separation of nervonic acid

Acer truncatum seed oil (ATSO) contains abundant unsaturated fatty acids, with significant quantities of nervonic acid (NA, > 5%), which was authenticated as a new food resource in China. For the sake of minimizing animal consumption and the importance of NA for human health, extraction of NA from plants has become a research hotspot. In the present study, three extraction factors were determined to significantly influence the saponification reaction based on single-factor experiments: NaOH dosage, reaction time, and reaction temperature. These three factors were used to further optimize the saponification process through the response surface methodology, and the highest yield of mixed fatty acids was 83.12%. Moreover, the activation energy (40.8228 kJ/mol), the pre-exponential factor [2.568 × 10⁶ m³ /(kmol·min)], and the kinetic equation [r_A = kc_A c_B = 2.568 × 10⁶ ·exp(- 4970 . 1 T ) $\frac{{{\rm{4970}}{\rm{.1}}}}{{\rm{T}}})$ c_A c_B ] of the ATSO saponification reaction were determined by combining the chemical reaction rate equation of the elementary reaction, the Arrhenius equation, and the NaOH concentration in the substrate. Finally, the mixed fatty acids of ATSO were crystallized by triple-stage low-temperature crystallization, and we achieved 25.05% purity for NA. This study provides a technological basis and strategy for specific fatty acid production from ASTO, as well as other vegetable oils important in the field of food and health supplement products. PRACTICAL APPLICATION: Nervonic acid (NA) is an essential component of neural cells and neural tissue, and it is vital for maintaining the normal work of nerve tissues in organisms and promotes neurodevelopment. NA has traditionally been mainly obtained from shark hunting, which is now restricted due to an international ban on shark fishing. The alternative way to produce NA cheaply and in large quantities is from plant sources. The techniques utilized in this study provide an effective method of NA separation from Acer truncatum seed oil for industrial production.

ABSCISIC ACID-INSENSITIVE 5-ω3 FATTY ACID DESATURASE3 module regulates unsaturated fatty acids biosynthesis in Paeonia ostii

Paeonia ostii is an authorized novel vegetable oil crop due to its seeds rich in unsaturated fatty acids (UFAs) especially α-linolenic acid (ALA), which overweight the current available edible oil. However, little is known on the regulation mechanism of UFAs biosynthesis during its seed development. Here, we used transcriptome and proteome data combining phytochemistry means to uncover the relationship between abscisic acid (ABA) signaling and UFAs biosynthesis during P. ostii seed development. Based on transcriptome and proteome analysis, two desaturases of omega-6 and omega-3 fatty acid, named as PoFAD2 and PoFAD3 responsible for ALA biosynthesis were identified. Then, an ABSCISIC ACID-INSENSITIVE 5 (ABI5) proteins was identified as an upstream transcriptional factor, which activated the expression of PoFAD3 instead of PoFAD2. Moreover, silencing of PoABI5 repressed the response of PoFAD3 to ABA. This study provides the first view on the connection between the function of ABA signaling factors and ALA biosynthesis in the P. ostii seed, which lays the foundation for studies on the regulatory mechanism of ABA signaling involved in the UFAs synthesis during seeds development, meanwhile, it will shed light on manipulation of ALA content for satisfying human demands on high quality of edible oil or healthy supplement.

Characterization of the Volatile Compounds in Camellia oleifera Seed Oil from Different Geographic Origins

Volatile flavor of edible oils is an important quality index and factor affecting consumer choice. The purpose of this investigation was to characterize virgin Camellia oleifera seed oil (VCO) samples from different locations in southern China in terms of their volatile compounds to show the classification of VCO with respect to geography. Different samples from 20 producing VCO regions were collected in 2020 growing season, at almost the same maturity stage, and processed under the same conditions. Headspace solid-phase microextraction (HS-SPME) with a gas chromatography–mass spectrometer system (GC–MS) was used to analyze volatile compounds. A total of 348 volatiles were characterized, including aldehydes, ketones, alcohols, acids, esters, alkenes, alkanes, furans, phenols, and benzene; the relative contents ranged from 7.80–58.68%, 1.73–12.52%, 2.91–37.07%, 2.73–46.50%, 0.99–12.01%, 0.40–14.95%, 0.00–27.23%, 0.00–3.75%, 0.00–7.34%, and 0.00–1.55%, respectively. The VCO geographical origins with the largest number of volatile compounds was Xixiangtang of Guangxi (L17), and the least was Beireng of Hainan (L19). A total of 23 common and 98 unique volatile compounds were detected that reflected the basic and characteristic flavor of VCO, respectively. After PCA, heatmap and PLS-DA analysis, Longchuan of Guangdong (L8), Qingshanhu of Jiangxi (L16), and Panlong of Yunnan (L20) were in one group where the annual average temperatures are relatively low, where annual rainfalls are also low. Guangning of Guangdong (L6), Yunan of Guangdong (L7), Xingning of Guangdong (L9), Tianhe of Guangdong (L10), Xuwen of Guangdong (L11), and Xiuying of Hainan (L18) were in another group where the annual average temperatures are relatively high, and the altitudes are low. Hence, volatile compound distributions confirmed the differences among the VCO samples from these geographical areas, and the provenance difference evaluation can be carried out by flavor.

Seed development in Paeonia ostii (Paeoniaceae), with particular reference to embryogeny

BACKGROUND

Seeds of Paeonia ostii have been proposed as a source of raw material for the production of edible oil; however, lack of information about the developmental biology of the seeds hampers our ability to use them. Our aim was to investigate development of the seed coat, endosperm and embryo of P. ostii in relation to timing of accumulation of nutrient reserves from pollination to seed maturity. Ovules and developing seeds of P. ostii were collected at various stages of development from zygote to maturity. Seed fresh mass, dry mass, germination, moisture, soluble sugars, starch, protein and oil content were determined. Ontogeny of seeds including embryo, endosperm and seed coat were analyzed histologically.

RESULTS

The ovule of P. ostii is anatropous, crassinucellate and bitegmic. The zygote begins to divide at about 5 days after pollination (DAP), and the division is not accompanied by cell wall formation. By 25 DAP, the proembryo begins to cellularize. Thereafter, several embryo primordia appear at the surface of the cellularized proembryo, but only one matures. Endosperm development follows the typical nuclear type. The seed coat is derived from the outer integument. During seed development, soluble sugars, starch and crude fat content increased and then decreased, with maximum contents at 60, 80 and 100 DAP, respectively. Protein content was relatively low compared with soluble sugars and crude fat, but it increased throughout seed development.

CONCLUSIONS

During seed development in P. ostii, the seed coat acts as a temporary storage tissue. Embryo development of P. ostii can be divided into two stages: a coenocytic proembryo from zygote (n + n) that degenerates and a somatic embryo from peripheral cells of the proembryo (2n → 2n). This pattern of embryogeny differs from that of all other angiosperms, but it is similar to that of gymnosperms.

Phytochemical profiles and the hypoglycemic effects of tree peony seed coats

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.

Impact of Drying Methods on Phenolic Components and Antioxidant Activity of Sea Buckthorn (Hippophae rhamnoides L.) Berries from Different Varieties in China

Sea buckthorn berries are rich in bioactive compounds and can be used for medicine and food. The variety and drying method used have an important influence on quality. In this study, different sea buckthorn varieties from China were selected and dried with four common drying methods. The total phenolic content (TPC), total flavonoids content (TFC), contents of 12 phenolic compounds and antioxidant capacity in vitro were analyzed. The results showed that the TPC, TFC and antioxidant activity of two wild sea buckthorn berries were higher than those of three cultivated berries, and for the same varieties, measured chemical contents and antioxidant activity of the freeze-dried fruit were significantly higher than those obtained with three conventional drying methods. In addition, forty-one compounds in sea buckthorn berry were identified by UPLC-PDA-Q/TOF-MS, most of which were isorhamnetin derivatives. Multivariate statistical analysis revealed narcissin and isorhamnetin-3-O-glucoside varied significantly in sea buckthorn berries of different varieties and with different drying methods; they were potential quality markers. Strong correlations were found between TPC, gallic acid and antioxidant capacity (p < 0.05). The results revealed how components and antioxidant activity varied in different sea buckthorn, which provides a valuable reference for quality control and further development and utilization of sea buckthorn.

Enzyme-assisted Solvent Extraction of High-yield Paeonia suffruticosa Andr. Seed Oil and Fatty Acid Composition and Anti-Alzheimer's Disease Activity

Enzyme-assisted solvent extraction (EASE) of Paeonia suffruticosa Andr. seed oil (PSO) was optimized by response surface methodology (RSM). The fatty acid composition and anti-Alzheimer's disease (AD) activity of PSO were analyzed. An enzyme mixture composed of cellulase and hemicellulase (1:1, w/w) was most effective in determining the extraction yield of PSO. The ideal extraction conditions were a pH value of 5.1, an enzymolysis time of 68 min, and a temperature of 50℃. The average extraction yield of PSO was 38.2 mL/100 g, 37.4% higher than that of untreated peony seed (27.8 mL/100 g). The fatty acid composition of PSO under optimal conditions for EASE was analyzed by gas chromatography-mass spectrometry (GC-MS). The predominant unsaturated fatty acids of PSO were determined to be more than 90.00%, including n-3 α-linolenic acid (43.33%), n-6 linoleic acid (23.40%) and oleic acid (23.59%). In this experiment, the anti-AD effect of PSO was also analyzed by performing learning and memory ability tests with Drosophila. PSO retarded the decrease in climbing ability in AD Drosophila. The 1% and 5% PSO groups were significantly different from the model group (^b p < 0.05). The smell short-term memory ability test revealed the number of Drosophila in barrier and barrier-free centrifuge tubes in each group. PSO feeding improved learning and memory in AD Drosophila, with the highest number entering the barrierfree centrifuge tube. The performance index (PI) measured by the Pavlov olfactory avoidance conditioning test also demonstrated the effect of PSO on the learning and memory abilities of Drosophila. The PI of the PSO group was significantly increased compared to that of the model group. HE-stained brain tissue sections of AD Drosophila showed higher neurodegenerative changes, while PSO significantly reduced neurodegenerative damage. These results indicated that PSO can significantly improve the cognitive function of AD Drosophila and may help to prevent AD.

Ecotopic over-expression of PoCHS from Paeonia ostii altered the fatty acids composition and content in Arabidopsis thaliana

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 homolog 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 homolog of P. ostii and demonstrated its new function in seed fatty acid biosynthesis.

Transcriptomic analysis of α-linolenic acid content and biosynthesis in Paeonia ostii fruits and seeds

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.

Expression profiles of genes involved in fatty acid and lipid biosynthesis in developing seeds of Paeonia ostii

BACKGROUND

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.

OBJECTIVES

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Morphological, Anatomical, and Phytochemical Studies of Carlina acaulis L. Cypsela

Carlina acaulis L. has a long tradition of use in folk medicine. The chemical composition of the roots and green parts of the plant is quite well known. There is the lowest amount of data on the cypsela (fruit) of this plant. In this study, the microscopic structures and the chemical composition of the cypsela were investigated. Preliminary cytochemical studies of the structure of the Carlina acaulis L. cypsela showed the presence of substantial amounts of protein and lipophilic substances. The chemical composition of the cypsela was investigated using spectrophotometry, gas chromatography with mass spectrometry, and high-performance liquid chromatography with spectrophotometric and fluorescence detection. The cypsela has been shown to be a rich source of macro- and microelements, vegetable oil (25%), α-tocopherol (approx. 2 g/kg of oil), protein (approx. 36% seed weight), and chlorogenic acids (approx. 22 g/kg seed weight). It also contains a complex set of volatile compounds. The C. acaulis cypsela is, therefore, a valuable source of nutrients and bioactive substances.

Bioactive components, antioxidant and antimicrobial activities of Paeonia rockii fruit during development

In last ten years, much attention focused on tree peony fruit (TPF) for edible oil production despite other potential utilization. The present study identified and quantified 29 bioactive components by liquid chromatography-electrospray ionization-triple quadrupole-mass spectrometry (LC-ESI-QqQ-MS) targeted approach during the development of TPF. Trans-resveratrol, benzoic acid, luteolin, and methyl gallate were selected as predominant chemical markers between seeds and pods through principal component analysis (PCA) and orthogonal partial least square-discriminant analysis (OPLS-DA). Extremely high levels of paeoniflorin (1893 mg/100 g) and trans-resveratrol (1793 mg/100 g) were observed at stage 2 (S2) and S6 in seeds, respectively. Antioxidant activities determined by ABTS^+•, DPPH^•, and FRAP assays showed significant correlations with total phenolic content (TPC) and total flavonoid content (TFC). The strongest antibacterial effects of pod and seed against Staphylococcus aureus and Proteus vulgaris occurred at initial stages and maturation stages. TPF could be a potential source of bioactive compounds with functional properties.

Integrated Profiling of Fatty Acids, Sterols and Phenolic Compounds in Tree and Herbaceous Peony Seed Oils: Marker Screening for New Resources of Vegetable Oil

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, γ-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 α-linolenic acid (39.0–48.3%), while β-sitosterol (1802.5–2793.7 mg/kg) and fucosterol (682.2–1225.1 mg/kg) were the dominant phytosterols. Importantly, 34 phenolic compounds, including paeonol and “Paeonia glycosides” (36.62–103.17 μg/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 “Paeonia glycosides”.