Qingyan Shu

Flavonoid composition and antioxidant activity of tree peony (Paeonia section moutan) yellow flowers.

Tree peony flowers are edible and traditional Chinese medicine materials. In the present study, 26 flavonoids were identified and quantified in yellow flowers of tree peony by high-performance liquid chromatography with diode array detector (HPLC-DAD) and by HPLC-electrospray ionization-mass spectrometry (HPLC-ESI-MS). Seventeen of them were first reported in flowers of tree peony, and glycosides of kaempferol, luteolin, and apigenin as well as isosalipurposide were the main flavonoids investigated. Furthermore, the petal extracts showed high antioxidant activity according to DPPH*, ABTS*(+), and OH* scavenging assays and ferric reducing antioxidant power assay. There were significant correlations between antioxidant activity and both the total polyphenol content (determined by Folin-Ciocalteu method) and the total content of quercetin, kaempferol, and luteolin glycosides. This work is valuable for elucidation of phenolic composition in tree peony flowers and for further utilization of them as functional food and medicine materials.

Studies on Paeonia cultivars and hybrids identification based on SRAP analysis.

Plants of Paeonia are valuable for their ornamental and medicinal values. Genetic relations and hybrids identification among different sections of Paeonia were studied using sequence related amplified polymorphism (SRAP) markers. A total of 29 cultivars including 2 intersectional hybrids, 13 sect. Moutan and 14 from sect. Paeonia were used. A total of 197 bands were produced using 24 primer combinations, among which 187 bands showed polymorphism. From the bands amplified, we can identify the peony cultivars using unique SRAP markers and specific primer combinations. Fourteen peony cultivars were distinguished among each other by using totally 35 SRAP markers, which were generated by 16 primer pairs. Two specific primer pairs of Me8/Em8 and Me8/Em1 can be used to identify cultivars from different sections. The mean genetic similarity coefficient (GS), the gene diversity (GD), and the Shannons information index of peony cultivars were 0.45, 0.19 and 0.32, respectively. Both UPGMA (unweighted pair-group method of arithmetic average) dendrogram and PCA (principle component analysis) analysis showed clear genetic relationships among the 29 peony cultivars, and within section and its intersectional hybrids. The above results are valuable for estimating and analyzing genetic background of Paeonia, parent selection in crossing breeding programs, molecular marker assisted selection (MAS) breeding for further germplasm innovation programs.

Fatty acid composition of developing tree peony (Paeonia section Moutan DC.) seeds and transcriptome analysis during seed development

BackgroundTree peony (Paeonia section Moutan DC.) is known for its excellent ornamental and medicinal values. In 2011, seeds from P. ostii have been identified as novel resource of α-linolenic acid (ALA) for seed oil production and development in China. However, the molecular mechanism on biosynthesis of unsaturated fatty acids in tree peony seeds remains unknown. Therefore, transcriptome data is needed to better understand the underlying mechanisms.ResultsIn this study, lipid accumulation contents were measured using GC-MS methods across developing tree peony seeds, which exhibited an extraordinary ALA content (49.3%) in P. ostii mature seeds. Transcriptome analysis was performed using Illumina sequencing platform. A total of 144 million 100-bp paired-end reads were generated from six libraries, which identified 175,874 contigs. In the KEGG Orthology enrichment of differentially expressed genes, lipid metabolism pathways were highly represented categories. Using this data we identified 388 unigenes that may be involved in de novo fatty acid and triacylglycerol biosynthesis. In particular, three unigenes (SAD, FAD2 and FAD8) encoding fatty acid desaturase with high expression levels in the fast oil accumulation stage compared with the initial stage of seed development were identified.ConclusionsThis study provides the first comprehensive genomic resources characterizing tree peony seeds gene expression at the transcriptional level. These data lay the foundation for further understanding of molecular mechanism responsible for lipid biosynthesis and the high unsaturated fatty acids (especially ALA) accumulation. Meanwhile, it provides theoretical base for potential oilseed application in the respect of n-6 to n-3 ratio for human diets and future regulation of target healthy components of oils.

Determination of Anthocyanins and Exploration of Relationship between Their Composition and Petal Coloration in Crape Myrtle （Lagerstroemia hybrid）

Petal coloration and pigment components in 12 American crape myrtle cultivars (Lagerstroemia indicaxLagerstroemia fauriei) and five Chinese crape myrtle cultivars (L. indica hybrids) were studied. Color was measured by CIEL*a*b* scale and anthocyanin composition of crape myrtle was determined using high-performance liquid chromatography coupled to photodiode array detection and electrospray ionization mass spectrometry. The presence of the previously reported delphinidin 3-O-glucoside, petunidin 3-O-glucoside and malvidin 3-O-glucoside were confirmed. Cyanidin 3-O-glucoside was identified in crape myrtle for the first time. We explored the relationship between petal color and anthocyanin contents by multiple linear regression analyses. The results indicated that total flavones and flavonols were important variables and contributed to blue-enhancing in crape myrtle. Based on anthocyanins and co-pigments analysis, flower color breeding in crape myrtle towards true-red and blue were discussed.

Relationship between the Composition of Flavonoids and Flower Colors Variation in Tropical Water Lily (Nymphaea) Cultivars

Water lily, the member of the Nymphaeaceae family, is the symbol of Buddhism and Brahmanism in India. Despite its limited researches on flower color variations and formation mechanism, water lily has background of blue flowers and displays an exceptionally wide diversity of flower colors from purple, red, blue to yellow, in nature. In this study, 34 flavonoids were identified among 35 tropical cultivars by high-performance liquid chromatography (HPLC) with photodiode array detection (DAD) and electrospray ionization mass spectrometry (ESI-MS). Among them, four anthocyanins: delphinidin 3-O-rhamnosyl-5-O-galactoside (Dp3Rh5Ga), delphinidin 3-O-(2″-O-galloyl-6″-O-oxalyl-rhamnoside) (Dp3galloyl-oxalylRh), delphinidin 3-O-(6″-O-acetyl-β-glucopyranoside) (Dp3acetylG) and cyanidin 3- O-(2″-O-galloyl-galactopyranoside)-5-O-rhamnoside (Cy3galloylGa5Rh), one chalcone: chalcononaringenin 2′-O-galactoside (Chal2′Ga) and twelve flavonols: myricetin 7-O-rhamnosyl-(1→2)-rhamnoside (My7RhRh), quercetin 7-O-galactosyl-(1→2)-rhamnoside (Qu7GaRh), quercetin 7-O-galactoside (Qu7Ga), kaempferol 7-O-galactosyl-(1→2)-rhamnoside (Km7GaRh), myricetin 3-O-galactoside (My3Ga), kaempferol 7-O-galloylgalactosyl-(1→2)-rhamnoside (Km7galloylGaRh), myricetin 3-O-galloylrhamnoside (My3galloylRh), kaempferol 3-O-galactoside (Km3Ga), isorhamnetin 7-O-galactoside (Is7Ga), isorhamnetin 7-O-xyloside (Is7Xy), kaempferol 3-O-(3″-acetylrhamnoside) (Km3-3″acetylRh) and quercetin 3-O-acetylgalactoside (Qu3acetylGa) were identified in the petals of tropic water lily for the first time. Meanwhile a multivariate analysis was used to explore the relationship between pigments and flower color. By comparing, the cultivars which were detected delphinidin 3-galactoside (Dp3Ga) presented amaranth, and detected delphinidin 3′-galactoside (Dp3′Ga) presented blue. However, the derivatives of delphinidin and cyanidin were more complicated in red group. No anthocyanins were detected within white and yellow group. At the same time a possible flavonoid biosynthesis pathway of tropical water lily was presumed putatively. These studies will help to elucidate the evolution mechanism on the formation of flower colors and provide theoretical basis for outcross breeding and developing health care products from this plant.

Antioxidant capacities and anthocyanin characteristics of the black-red wild berries obtained in Northeast China.

Various edible berries widely accessible in nature in Northeast China are poorly exploited. The compositions and contents of anthocyanins in black (Padus maackii, Padus avium, Lonicera caerulea, and Ribes nigrum) and red (Ribes rubrum, Sambucus williamsii, Rubus idaeus, and Ribes procumbens) wild berries in Northeast China were firstly characterized by HPLC-DAD/ESI-MS(2). Twenty-three anthocyanins were detected and identified. Cyanidin glycosides were dominant in both berries. Six anthocyanins were reported for the first time in P. avium, R. rubrum, and Sambucus. Total anthocyanin content (TAC) ranged from 10mg/100gfreshweight (FW) (R. procumbens) to 1058mg/100gFW (P. maackii) among berries. The TACs and antioxidant activities assessed by DPPH and FRAP assays were much higher in black than in red berries. Black-red berries, especially P. maackii and P. avium, can be used in developing functional foods and in improving breeding programs.

Flavone synthases from Lonicera japonica and L. macranthoides reveal differential flavone accumulation

Flavones are important secondary metabolites found in many plants. In Lonicera species, flavones contribute both physiological and pharmaceutical properties. However, flavone synthase (FNS), the key enzyme responsible for flavone biosynthesis, has not yet been characterized in Lonicera species. In this study, FNSII genes were identified from Lonicera japonica Thunb. and L. macranthoides Hand.-Mazz. In the presence of NADPH, the recombinant cytochrome P450 proteins encoded by LjFNSII-1.1, LjFNSII-2.1, and LmFNSII-1.1 converted eriodictyol, naringenin, and liquiritigenin to the corresponding flavones directly. The different catalytic properties between LjFNSII-2.1 and LjFNSII-1.1 were caused by a single amino acid substitution at position 242 (glutamic acid to lysine). A methionine at position 206 and a leucine at position 381 contributed considerably to the high catalytic activity of LjFNSII-1.1. In addition, LjFNSII-1.1&2.1 and LmFNSII-1.1 also biosynthesize flavones that were further modified by O-glycosylation in transgenic tobacco. The expression levels of the FNSII genes were consistent with flavone accumulation patterns in flower buds. Our findings suggested that the weak catalytic activity of LmFNSII-1.1 and the relatively low expression of LmFNSII-1.1 in flowers might be responsible for the low levels of flavone accumulation in flower buds of L. macranthoides.

Methylation mediated by an anthocyanin, O-methyltransferase, is involved in purple flower coloration in Paeonia

Highlight A single amino acid residue substitution at position 87 from arginine to leucine of AOMT is vital for anthocyanin methylation in Paeonia plants, especially for purple flower coloration.

Analysis of the formation of flower shapes in wild species and cultivars of tree peony using the MADS-box subfamily gene

Tree peony (Paeonia suffricotisa) cultivars have a unique character compared with wild species; the stamen petalody results in increased whorls of petals and generates different flower forms, which are one of the most important traits for cultivar classification. In order to investigate how petaloid stamens are formed, we obtained the coding sequence (666 bp) and genomic DNA sequence of the PsTM6 genes (belongs to B subfamily of MADS-box gene family) from 23 tree peony samples, Five introns and six exons consisted of the genomic DNA sequence. The analysis of cis-acting regulatory elements in the third and fourth intron indicated that they were highly conserved in all samples. Partial putative amino acids were analyzed and the results suggested that functional differentiation of PsTM6 paralogs apparently affected stamen petalody and flower shape formation due to due to amino acid substitution caused by differences in polarity and electronic charge. Sliding window analysis indicated that the different regions of PsTM6 were subjected to different selection forces, especially in the K domain. This is the first attempt to investigate genetic control of the stamen petalody based on the PsTM6 sequence. This will provide a basis for understanding the evolution of PsTM6 and its the function of in determining stamen morphology of tree peony.

Genetic relationship in ecotypes of Leymus chinensis revealed by polymorphism of amplified DNA fragment lengths

Leymus chinensis (Trin.) Tzvel is a perennial grass in the tribe Gramineae and important forage in Northern China. Knowledge of its genetic diversity is a prerequisite for using modern breeding techniques. Amplified fragment length polymorphism (AFLP) was first used to evaluate the genetic relationship among and within three ecotypes. Distinct clusters were produced based on AFLP markers. All accessions from the same ecotype were grouped in a cluster except accessions 6. According to AFLP profile ecotype-specific bands differ from each other. The genetic differentiation within the ecotype of the species was much smaller than that among ecotypes. Self-incompatibility in this species contributes to evident genetic differentiation together with environment. These results indicate that ecotypes were distinguished visually similarly to genetic variation.