Tree peony (Paeonia suffruticosa Andrews) is a globally famous ornamental flower, with large and colorful flowers and abundant flower types. However, a relatively short and uniform flowering period ...hinders the applications and production of ornamental tree peony. Unfortunately, the molecular mechanism of regulating flowering time and floral organ development in tree peony has yet to be elucidated. Because of the absence of genomic information, 454-based transcriptome sequence technology for de novo transcriptomics was used to identify the critical flowering genes using re-blooming, non-re-blooming, and wild species of tree peonies.
A total of 29,275 unigenes were obtained from the bud transcriptome, with an N50 of 776 bp. The average length of unigenes was 677.18 bp, and the longest sequence was 5815 bp. Functional annotation showed that 22,823, 17,321, 13,312, 20,041, and 9940 unigenes were annotated by NCBI-NR, Swiss-Prot, COG, GO, and KEGG, respectively. Within the differentially expressed genes (DEGs) 64 flowering-related genes were identified and some important flowering genes were also characterized by bioinformatics methods, reverse transcript polymerase chain reaction (RT-PCR), and rapid-amplification of cDNA ends (RACE). Then, the putative genetic network of flowering induction pathways and a floral organ development model were put forward, according to the comparisons of DEGs in any two samples and expression levels of the important flowering genes in differentiated buds, buds from different developmental stages, and with GA or vernalization treated. In tree peony, five pathways (long day, vernalization, autonomous, age, and gibberellin) regulated flowering, and the floral organ development followed an ABCE model. Moreover, it was also found that the genes PsAP1, PsCOL1, PsCRY1, PsCRY2, PsFT, PsLFY, PsLHY, PsGI, PsSOC1, and PsVIN3 probably regulated re-blooming of tree peony.
This study provides a comprehensive report on the flowering-related genes in tree peony for the first time and investigated the expression levels of the critical flowering related genes in buds of different cultivars, developmental stages, differentiated primordium, and flower parts. These results could provide valuable insights into the molecular mechanisms of flowering time regulation and floral organ development.
Itoh hybrids are intersectional hybrids in Paeonia L. with sect. Moutan and sect. Paeonia as paternal and maternal parents, respectively. Therefore, these hybrids have herbaceous stems with improved ...ornamental value introduced by the paternal parent. Although both of their parents are diploids, Itoh hybrids are triploids. Moreover, the parental origin of their chromosomes has not been extensively studied. This study systematically analyzed the genome size, ploidy, and karyotype of Itoh hybrids and compared them with their parental taxa. Although the monoploid genome size of Itoh hybrids was different, it was not significantly different from that of the parents. However, the size of varieties in the two parental taxa was significantly different from the wild species, probably due to genome rearrangements caused by artificial selection. Further karyotype analysis, correlation analysis, and hierarchical clustering could not identify the parental origin of chromosomes in Itoh hybrids. Verification through genomic and fluorescence in situ hybridization (GISH and FISH) suggested that for the three sets of chromosomes in Itoh hybrids, two were from the paternal parent, and one was from the maternal parent. One of the first two sets was from wild species, and the other from a cultivated variety. GISH could not label the chromosomes of cultivated peonies from the sect. Moutan, probably due to the huge and complex genomes compared with the wild species. Meanwhile, 5S rDNA-based FISH was first applied in Paeonia, which may be used for ploidy assessment. This work may give insights into the utilization of Itoh hybrid resources.
In this study, the quality changes of grass carp during tea polyphenol-assisted curing were studied from physicochemical and flavor perspectives. The addition of tea polyphenols has a positive effect ...on maintaining the water content of fish as the curing time increases (p < 0.05). The tea polyphenol-assisted treatment maintains the brightness of grass carp meat. The addition of tea polyphenols also slowed down the rate of pH growth and enhances the texture of grass carp (p < 0.05). The addition of tea polyphenols reduced His content, which had a positive effect on the taste of the cured grass carp products. When the pickling time reached 60 min, the inosine monophosphate content of tea polyphenol-treated groups was higher than that of the group soaked in salt only. Combined with equivalent umami concentration and taste activity values, it was found that the addition of 0.1% TP could improve freshness of grass carp cured products.
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•Sucrose treatment improved cut peony vase quality by prolonging vase life.•Sucrose treatment prolonged the number of days when the flowers were fully opened.•Both energetic and ...osmotic processes may be involved in vase quality improvement.•Both SUTs and INVs may be involved in regulating the vase quality of cut flowers.
Cut peonies (Paeonia lactiflora Pall.) have become increasingly popular worldwide in recent years. However, the limited vase life and often poor vase quality have negatively affected the commercial development of this ornamental flower. In this study, 20 g L−1 sucrose was added to the vase solution of cut peony (‘Yang Fei Chu Yu’) to better understand the effect of sucrose on the vase quality. The results showed that sucrose treatment increased the number of days during which the flowers were fully opened by approximately 1.3 d, whereas treatment effects on the opening process were limited. Sucrose treatment delayed the decrease in flower fresh weight and sucrose concentration of the petals, while increasing glucose and fructose concentrations. Two sucrose transporter (SUT) genes, PlSUT1 and PlSUT2, and five invertase (INV) genes, PlCWIN1, PlVIN1, PlCIN1, PlCIN2 and PlCIN3, were isolated from a peony transcriptional database. Gene expression by RT-qPCR showed that both PlSUT2 and PlSUT4 were induced by sucrose treatment, indicating their putative role in transporting sucrose from the vase solution to the flowers. Among the five INVs, the expression of PlCWIN1 was greater in sucrose-treated flowers than in the controls from day 3 to the end of the vase period, indicating its possible role in increasing the number of days when the flowers were fully opened. The expression of PlVIN1 decreased in control flowers, but was delayed by sucrose treatment, especially on day 3. Since PlVIN1 was predicted to be located in the vacuole, it is highly possible that the expression of PlVIN1 helped to increase the vacuolar osmotic potential through the accumulation of glucose and fructose, thereby increasing water uptake for maintenance of flowers at the fully opened stage. Among the three PlCINs, the expression of PlCIN2 was much higher in sucrose-treated than in the control flowers throughout the vase period, indicating its major role in improving vase quality through sucrose treatment. Our study indicates that both SUTs and INVs are involved in maintaining the vase quality of cut peony flowers.
Tree peony has nine wild species, but the evolutionary relationship of them is still unclear. Here, a total of 274 specimens from 22 natural populations of nine wild species were collected, and their ...genetic diversity and similarity was analyzed based on Simple Sequence Repeats (SSR) molecular markers. A total of 106 alleles were generated based on 20 primers and with an average of 5.3 alleles per primer. Shannon's information index (I) ranged from 0.6333 to 1.7842, and the average of Nei's genetic diversity coefficient (H) was 0.5771. Polymorphism Information Content (PIC) value varied from 0.29 to 0.77, ten of these primers had high polymorphism (PIC ≥ 0.50). All the above genetic parameters of primers reflect more rich genetic diversity information compared with other researches using SSR molecular markers to study the genetic diversity of tree peony wild species. At the population level, the lowest and highest degree of genetic diversity occurred in Paeonia ludlowii-P1 and P. delavayi-P3 population, respectively. Whereas at species level, the genetic diversity of 9 wild peony species was as follows: P. lutea > P. delavayi > P. rockii > P. qiui > P. ostii > P. decomposita > P. potaninii > P. spontanea > P. ludlowii. Furthermore, cluster analysis at species level divided the nine wild tree peony species into two branches. In branch I, the closest phylogenetic relationship was found between P. ostii and P. rockii, followed by P. spontanea, P. qiui, and P. decomposita. In branch II, the closest relationship occurred between P. lutea and P. delavayi, followed by P. potaninii and P. ludlowii. Clustering results supported the division of tree peonies into two subsects (Delavayanae and Vaginatae), it also supported P. potaninii and P. ludlowii as independent species. The results provided novel insight into the genetic diversity and phylogenetic relationship of nine wild tree peony species. It will help formulate comprehensive protection measures of wild germplasm resources and select proper parents for distant hybridization in the future.
Light quality strongly impacts the growth and flower quality of ornamental plants. The optimum light quality for the growth and flowering of
remains to be validated. In the present study, we ...investigated the effect of the red/blue light ratio of LEDs on the growth and flowering quality of
'Red Lion'. Two LEDs with red/blue light ratio of 1:9 (R
B
) and 9:1 (R
B
) were designed. LEDs of white light were the control. In the earlier vegetative and reproductive growth phase, R
B
increased the biomass of the bulbs, leaves, and flowers. Compared with the control and R
B
group, R
B
LEDs delayed flowering by 2.30 d and 3.26 d, respectively. Based on chlorophyll contents, photosynthetic capacity, chlorophyll fluorescence parameters, and carbohydrate contents, the photosynthesis rate was higher in the R
B
group. Optimal red and blue light intensity promoted the accumulation of carbohydrates and early flowering and prolonged the flowering period of
. Microscopic analysis showed that stomatal density was high, and the number of chloroplasts was large in the R
B
treatment group, which enhanced photosynthesis. Particularly, R
B
promoted the expression of seven key genes related to chlorophyll synthesis. R
B
also promoted early overexpression of the
gene that promotes early flowering. Thus, higher blue light and 10% red light intensities promote early and extended flowering, while higher red light and 10% blue light promote vegetative plant growth but delay flowering.
Gibberellin (GA) is frequently used in tree peony forcing culture, but inappropriate application often causes flower deformity. Here, 5-azacytidine (5-azaC), an efficient DNA demethylating reagent, ...induced tree peony flowering with a low deformity rate by rapidly inducing
expression, whereas GA treatment affected various flowering pathway genes with strong pleiotropy. The 5-azaC treatment, but not GA, significantly reduced the methylation level in the
promoter with the demethylation of five CG contexts in a 369 bp CG-rich region, and eight light-responsive related
-elements were also predicted in this region, accompanied by enhanced leaf photosynthetic efficiency. Through GO analysis, all methylation-closer differentially expressed genes (DEGs) were located in the
, the main site for photosynthesis, and were mainly involved in
and
, whereas GA-closer DEGs had a wider distribution inside and outside of cells, associated with 12 categories of processes and regulations. We further mapped five candidate DEGs with potential flowering regulation, including three kinases (
,
and
) and two bioactive enzymes (
and
). In summary, 5-azaC and GA may have individual roles in inducing tree peony flowering, and 5-azaC could be a preferable regulation approach; DNA demethylation is suggested to be more focused on flowering regulation with
playing a core role through promoter demethylation. In addition, 5-azaC may partially undertake or replace the light-signal function, combined with other factors, such as
, in regulating flowering. This work provides new ideas for improving tree peony forcing culture technology.
Mill. is a perennial herbaceous plant species, known for the medicinal value of all of its plant parts, although the chemical composition of the petals is unknown. This study aimed to determine the ...chemical fingerprint of the petals and also establish the optimal extraction parameters, extraction medium, and extraction method for petals collected from different localities in Serbia. The optimization was performed in order to acquire extracts that are rich in the contents of total polyphenol content (TPC) and total flavonoid content (TFC), and also exhibit strong antioxidant activity. In addition, the influence of the extracts on several human skin pathogens was evaluated, as well as their ability to aid wound closure and act as anti-inflammatory agents. Both the extraction medium and the applied technique significantly influenced the skin-beneficial biological activities, while methanol proved to be a more favorable extraction medium. In conclusion, the extraction conditions that yielded the extract with the richest phenolic content with satisfactory biological potential varied between the assays, while the most promising locality in Serbia for the collection of
petals was Pančevo (South Banat).
The flowering time of tree peony is short and concentrated in spring, which limits the development of its industry. We previously achieved tree peony reflowering in autumn. Here, we further shifted ...its reflowering time ahead through proper gibberellin (GA) treatment plus nutrient supply. GA treatment alone initiated bud differentiation, but it aborted later, whereas GA plus nutrient (G + N) treatment completed the opening process 38 days before the control group. Through microstructural observation of bud differentiation and starch grains, we concluded that GA plays a triggering role in flowering induction, whereas the nutriment supply ensured the continuous developing for final opening, and both are necessary. We further determined the expression of five floral induction pathway genes and found that PsSOC1 and PsLFY probably played key integral roles in flowering induction and nutrient supply, respectively. Considering the GA signaling, PsGA2ox may be mainly involved in GA regulation, whereas PsGAI may regulate further flower formation after nutrient application. Furthermore, G + N treatment, but not GA alone, inhibited the expression of PsTPS1, a key restricting enzyme in sugar signaling, at the early stage, indicating that sugar signaling is also involved in this process; in addition, GA treatment induced high expression of PsSnRK1, a major nutrient insufficiency indicator, and the induction of PsHXK1, a rate-limiting enzyme for synthesis of sugar signaling substances, further confirmed the nutrient shortage. In short, besides GA application, exogenous nutrient supply is essential to shift tree peony reflowering ahead in autumn under current forcing culture technologies.
Aquaporins are water channel proteins that facilitate the passage of water through biological membranes and play a crucial role in plant growth. We showed that ethylene treatment significantly ...reduced petal size, inhibited expansion of petal abaxial subepidermal cells, and decreased petal water content in rose (Rosa hybrida 'Samantha'). Here, we report the isolation of a plasma membrane aquaporin (PIP) gene, Rh-PIP2;1, and characterized its potential role in ethylene-inhibited petal expansion. Rh-PIP2;1 is mainly localized on the plasma membrane and belongs to the class 2 subfamily of PIP proteins. We show that Rh-PIP2;1 is an active water channel. The transcripts of Rh-PIP2;1 are highly abundant in petal epidermal cells, especially in the abaxial subepidermal cells. The expression of Rh-PIP2;1 is highly correlated with petal expansion and tightly down-regulated by ethylene. Furthermore, we demonstrate that in Rh-PIP2;1-silenced flowers, petal expansion was greatly inhibited and anatomical features of the petals were similar to those of ethylene-treated flowers. We argue that Rh-PIP2;1 plays an important role in petal cell expansion and that ethylene inhibits petal expansion of roses at least partially by suppressing Rh-PIP2;1 expression.
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